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Åbo Akademi University & University of Helsinki
Center for Functional Materials FUNMAT
Annual Report 2008
Edited by Jarl B. Rosenholm and Christina Luojola
Center for Functional Materials Porthansgatan 3‐5 20500 Åbo, Finland
http://www.funmat.fi
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FunMat Annual Report 2008
Contents
Foreword…………………………………………………………………………………….………… 4 1. Introduction…………………………………………………………………………………….. 6 2. Organization of the Functional Materials (FunMat) Centre……………… 8 3. Research..………………………………………………………………………………………… 9
3.1 Theses…………………………………………………………………………………………… 9 3.2 Projects…………………………………………………………………………………………. 15 3.2.1 Synthesis of functional inorganic particles and formulation of dispersions………………………………………………………………………. 15 3.2.2 Synthesis of organic particulate meso‐structures and core/ shell capsules………….………………………………………………………..…. 31 3.2.3 New generation of dispersing agents…..……………………………... 47 3.2.4 Substrate activity and compability for functional materials… 58 3.2.5 To understand the electrical, optical and magnetic properties of disordered organic materials………..……………….. 72 3.2.6 Printable active electronic sensors, indicators and devices…. 87 3.2.7 Functional materials printing (FunPrint) center……………………. 97
4. Publications……………………………………………………………………………………… 106 4.1 Theses……………………………………………………………………………..……………. 106 4.1.1 Doctoral theses…….………………………………………………..……………. 106 4.1.2 Master of Science theses………….…………………………..…………….. 106 4.2 Articles…………………………………………………………………………..…………….. 107 4.2.1 Articles in international refereed journals……..……..…………….. 107 4.2.2 Books and book chapters……………………..……………….……………. 115 4.2.3 Articles in refereed international edited volumes and conference proceedings………………….…………………….……………. 116 4.3 Åbo Akademi reports…………………………………………………….…………….. 118 4.4 Patents and paptent applications………………………………….…………….. 118
5. Visits and visitors……………………………………………………………………………. 119 5.1 Visitors to FunMat……………………………………………………..………………… 119 5.2 Visitors from FunMat………………………………………………..…………………. 119 6. Outreach………………………………………………………………………………………… 120
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Foreword The successful collaboration in material science between the universities in Turku led in 1994 to the establishment of the Centre of Expertise in Materials Research, financed by Ministry of Interior. Later, the efforts were concentrated on Materials Surface Techniques and the subsequent establishment of a commercial instrument center, Top Analytica Ltd. The overall strategy for the Center for Functional Materials (FunMat) was based on market surveys made by Turku Science Park and Foundation for New Technology. In 2006 the national responsibility for Printed Intelligence at the national Centre of Expertise program, Forest Industry Future was awarded to Turku Science Park Expertise Network for Printed Communication. In 2005 Åbo Akademi University launched an internal competition for research groups to receive extra funding for three years, set into disposal by the Foundation for Åbo Akademi University to “create strong research environments of international standing”. Out of the 28 proposals 14 were in 2005 selected for further evaluation by an international committee, consisting of: Professor Bengt Ankarloo and Professor Ole Elgström, Lund University, Professor Gunnar Svedberg, STFI‐Packforsk, Professor Morten Søndergaard, University of Copenhagen, Professor Lars Bäckman, Karolinska Institutet and Professor Udo Zanders, University of Economy, Stockholm. The Functional Materials Center (FunMat) for Printable Electro‐, Magnetic‐, Optical‐, Chemical‐, and Biofunctionalities was in 2005 selected as one of the four Åbo Akademi Centers of Excellence for the period 2006‐2008. Moreover, FunMat Center received financial support from the Ministry of Education, starting 2007. The collaboration was initiated through the establishment of Knowledge Network of Printed Media in 2005. An option was originally set for maintained or altered funding for 2009 and an extension to 2010 after an additional evaluation. In 2008 Professor Lars Bäckman, Karolinska Institutet, Professor Ole Elgström, Lund University, professor Bjørn Tore Gjertsen, University of Bergen and Professor Gunnar Svedberg, STFI‐Packforsk, conducted the planned evaluation. The conclusion concerning FunMat was: “It is no doubt that the research performed within the fields covered by FunMat Center will continue to have a leading position in Finland and also to be a highly acknowledged actor internationally. Funding should definitely continue but the overall aim to integrate and coordinate the research must be heavily emphasized”. Åbo Akademi University decided, however to reduce the funding for 2009 and not to provide any optional funding for 2010. The principal aim of the Åbo Akademi University Center of Excellence action was to promote consolidation of the winning research networks in order to be competitive in the Academy of Finland application for national Center of Excellence status. The requirements for such status
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were quite demanding. In the overall judgment, the expert panel accredited by the Academy of Finland had to rank the successful candidates, within their project field among the top 5% in the world! Out of the 113 preliminary applications, 44 research teams were asked to provide a full application. Out of these, 28 groups passed the 5% demand level. The finalists were then evaluated on societal relevance of their projects. Only 18 passed this final test and were elected as national Centers of Excellence for the period, 2008‐2013. The proposal of the Center for Functional Materials was evaluated by Professor Dieter Rehder, University of Hamburg, Professor Paul Gatenholm Chalmers University of Technology and Professor Harald Grossmann, Technical University of Dresden. As a result of the evaluation, FunMat was the only one of the four ÅAU teams winning the Center of Excellence status at the Academy of Finland! One important reason for this success was probably the integration of the research groups in supporting national graduate schools for researchers training, in particular Graduate School of Materials Research (GSMR) of which most partners hold a share. The Academy of Finland nominated Professor Ann‐Christine Albertsson, Royal Institute of Technology, Stockholm and Professor Ananth Dodabalapur, University of Texas at Austin as experts in the Advisory board. After reviewing the research activities at the first Advisory Board meeting in September 2008, one of the concluding remarks were, “The overall scope and composition of the CoE is very good. The area of emphasis – Functional Materials – is one which is of considerable scientific as well as technological importance. The composition of the FunMat team is also very good, with the leading scientists in this area in Finland participating. Finally, the leadership of Prof. Rosenholm is dynamic”. This report describes the organization and personnel at the Academy of Finland FunMat Center of Excellence. The projects active during the first quarter of existence are included as well as the theses and publications resulting from them. The projects do not fully match with those listed in the application, since a number of them has ended and are not relevant anymore. Only refereed publications for the years 2008‐2009 are listed. For additional information on the activities, the reader is referred to the homepage: www.funmat.fi with links to each partner. It is my sincere hope that this report convinces the reader that the activities have been focused and successful. Åbo, June 2009 Jarl B. Rosenholm Professor, Chairman
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1. Introduction In the application the FunMat activities were illustrated as an unbroken value chain including the following headings:
1. Materials, including synthesis and physico‐chemical modification 2. Functionalization by printing, coatings or films 3. Characterization and modeling of precursor materials and structures 4. Utilization by demonstration of performance of functionalized assembled structures,
papers and boards However, since all stages are inter‐related the project phases may be better understood as both, forward characterization cycles and feedback modeling cycles. The schematic diagram strives at demonstrating the dynamic nature of the research and the continuous need for multiple competences.
It is self‐evident that only a fraction of the research can be focused on the core target areas to which the FunMat financed researchers contribute. Instead, in order to develop new materials and processing techniques a substantial fraction of the research is only indirectly coupled to those goals. Such supportive research, provide merely the basic knowledge for the FunMat oriented projects. Through researchers at graduate schools, e.g. Graduate School of Materials Research the network could be expanded to a wider competence in material science.
Materials Functionalization Utilisation
Characterization
Modeling
Chemical synth. Printing Assembly Phys.Chem. mod. Coatings & Films Paper & Board
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Environment research provides basic training in general surface and colloid (nano) chemistry, thermodynamics, physics, etc. needed to design models, which optimally are successful in predicting the material properties and processes of importance for FunMat goals. In order to advance the FunMat goals, all core activities have been coordinated within five working groups by experienced researchers. The working groups are:
1. Synthesis of Functional Materials, coordinated by MSc Petri Pulkkinen 2. Printed Power Supplies, coordinated by Ass.Prof. Mika Lindén 3. Magnetic Sensors, coordinated by PhD Himadri Majumdar 4. Electrochromic Displays, coordinated by MSc Carl‐Johan Wikman 5. Sensor Arrays, coordinated by PhD Petri Ihalainen 6. Printing Methods and Equipments, coordinated by PhD Tapio Mäkelä
However, in order to emphasize the projects listed in the application, the outcome of the research will be presented under these headings, together with relevant publications. Since the topic areas have developed further from the heading and aims documented in the application, each project report is introduced with a modified heading and by a short summary written by the coordinators. The original project topics were: Project I: Synthesis of inorganic particulate meso‐structures and core/shell capsules, project leaders Professor Jarl B. Rosenholm and Ass.Prof. Mika Lindén Project II: Synthesis of organic particulate meso‐structures and core/shell capsules, project leader Carl‐Eric Wilén Project III: New generation of dispersing agents, project leader Professor Heikki Tenhu Project IV: Substrate activity and compability for functional materials, project leaders Professor Martti Toivakka and Professor Jouko Peltonen Project V: Electro‐optical and magnetic properties of functional materials, project leader Professor Ronald Österbacka Project 6: Functional Materials Printing (FunPrint) Center, project leader PhD Tapio Mäkelä Only refereed publications for the years 2008‐2009 are listed. For additional information on the activities, the reader is referred to the homepage: www.funmat.fi with links to each partner.
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2. Organization of the Functional Materials (FunMat) Centre
Executive Board ÅAU members: Professor Jarl Rosenholm (Chairman) Professor Ronald Österbacka (Vice chairman) Professor Carl‐Eric Wilén Professor Heikki Tenhu Professor Martti Toivakka Professor Jouko Peltonen Ass.prof. Mika Lindén FunPrint Lab. manager Tapio Mäkelä External member: Mining Councellor Tor Bergman International Scientific Advisory Board: Professor Ananth Dodapalapur, University of Texas at Austin Professor Ann‐Christine Albertsson, the Royal Institute of Technology
Polymer Chemistry (Heikki Tenhu)
ÅAU members (Laboratories)
FunMat Board (Jarl Rosenholm)
External members (International
Scientific Advisory Board)
Physical Chemistry (Jarl Rosenholm &
Mika Lindén)
Physics (Ronald Österbacka)
Polymer Technology (Carl‐Eric Wilén)
Paper Coating & Converting
(Martti Toivakka & Jouko Peltonen)
FunPrint Laboratory (Tapio Mäkelä)
Economical & Secretarial Service
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3. Research 3.1 Theses
The following Theses have been completed at the FunMat laboratories by the end of June, 2009.
Organized Nanostructures of Thermoresponsive Poly(N‐isopropylacrylamide) Block Copolymers Obtained Through Controlled RAFT Polymerization
Nuopponen, Markus University of Helsinki, Faculty of Science, Department of Chemistry Defence on May 9th, 2008 Opponent: Professor Eva Malmström, KTH, Stockholm
The self‐organization of synthetic preformed polymers into controllable nanostuctures is one of the most promising topics in the material science. However, the field of block copolymer self‐assembly is still relatively young and current polymeric materials are structurally rather simple compared to biological materials. Thus, novel generations of polymer‐based materials offer huge opportunities in material science. In this work, amphiphilic di‐ and triblock copolymers were synthesized by RAFT polymerization, and their organization into specific structures at nanoscale was studied. In all the block copolymer, one of the blocks was thermoresponsive poly(N‐isopropylacrylamide). Thus, polymers and studied materials were temperature sensitive. In addition, control over tacticity in N‐isopropylacrylamide polymerization was studied. The self‐organization in aqueous solutions was strongly affected by the tacticity and the block sequence. Amphiphilic polymers formed various micellar structures in aqueous solutions. These micellar microcontainers have applications in controlled drug delivery. Amphiphiles have also applications as dispersants in coatings and cosmetics. In bulk, all the stable block copolymer morphologies were observed for triblock copolymers. Hydrogels of triblock copolymers can be used as thermoresponsive membrane materials. Polymers synthesized through the RAFT polymerization can be directly used in the synthesis of polymer grafted nanoparticles. Gold nanoparticles have attracted great interest due to the fact that gold is the most stable and inert noble metal possessing unique surface properties and good conductivity. It was shown that the association and optical properties of the gold nanoparticles grafted with smart polymers can be widely varied by pH and temperature. This type of gold nanoparticles has applications in diagnostics, sensors and cell imaging.
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Towards printed electronic devices
Mäkelä, Tapio Åbo Akademi University, Faculty of Mathematics and Natural Sciences, Department of Physics Defence on May, 16th, 2008. Opponents: Professor Juha Hagberg, University of Oulu and Professor Ari Ivaska, Åbo Akademi University In this work, five different patterning methods were developed to demonstrate the processing possibilities of polyaniline (PANI). Two different dopants, camphorsulfonic acid (CSA) and dodecylbenzenesulfonic acid (DBSA), were used to achieve PANI with high electrical conductivity that was soluble in various solvents. These solutions were used as printing unks in the processing. PANI was used in step‐by‐step methods such as UV lithography and nanoimprinting lithography (NIL). The continuous methods used were rotogravure printing (GRAVURE), flexpgraphic printing (FLEXO) and roll‐to‐roll nanoimprinting lithography (rrNIL). Dimensions from from the submicrometre to the millimeter scale were demonstrated in both processing routes. The functionality of PANI within the studied methods is compared and problems in scaling up to high‐volume manufacturing are discussed.
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Lactoyl (Co)Polymers Prepared by iron Carboxylate Catalysis
Stolt, Mikael Åbo Akademi University, Faculty of Technology, Department of Chemical Engineering, Laboratory of Polymer Technology Defence on May 16th, 2008. Opponent Professor Ann‐Christine Albertsson, the Royal Institute of Technology, Stockholm The objective of this thesis was to study whether iron compounds, and especially ferrous carboxylates, could be an alternative catalyst for preparing lactoyl baes polymers. Three well established polymerization techniques were chosen as different approaches to reach the goal. Firstly, ring‐opening polymerization was elucidated for making high molar mass polymers. Secondly, polycondensated telechelic prepolymers of poly(lactid acid) were made with subsequent urethane‐linking in order to make high molar mass poly(ester‐urethanes), and
thirdly low molar mass poly(ε‐caprolactone‐b‐lactid acid) polymers were made by polycondensation with an application in hot melt adhesives as the objective. The ferrous carboxylates were studied with respect to the activity in the reactions, as well as for other possible effects on the polymer properties in comparison to the frequently used stannous 2‐ethylhexanoate catalyst. The ferrous acetate shows a lower activity towards ring‐opening polymerization than the currently used tin compounds and is such not suitable on an industrial scale when preparing lactoyl polymers for commodity use. A long activation phase is observed in the polymerization and a high temperature is required in order to have an efficient polymerization. On the other hand, the optical purity of the polymer decreases significantly when a high polymerization temperature is used. The low toxicity of the iron compound makes it better suited for preparation of polymers for medical applications. The amount of used catalyst does not have any significant impact on the degradation behavior of the polymer. Iron carboxylates are potential catalysts in the two step preparation of poly(esterurethane)s, although the reactivity is lower than for stannous 2‐ethylhexanoate. The major advantages are that the semi‐crystalline nature of the polymers can be retained through both reaction steps and that the poly(lactic acid) show a high degree of hydroxyl‐termination when preparing telechelic prepolymers. A somewhat slower condensation reaction is obtained by using ferrous acetate than when
using stannous 2‐ethylhexanoate also in the poly(ε‐caprolactone‐b‐lactid acid) synthesis. The ferrous catalyst yields though a polymer blend with significantly less discoloration and better thermal stability compared to a stannous 2‐ethylhexanoate‐catalyzed formulation. The better thermal stability is crucial in hot‐melt applications where the polymer may be stored in a molten state for an extended period of time.
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Modular Design of Mesoporous Silica Materials: Towards Multifunctional Drug Delivery Systems Rosenholm Jessica Åbo Akademi University, Faculty of Technology, Department of Chemical Engineering, Department of Physical Chemistry Defence on May 30th, 2008. Opponent: Dr. Michael Tiemann, Justus‐Liebig‐Universität, Giessen Strategies for modular design of mesoporous silica materials with focus on applications within the field of biomedicine, mainly drug delivery, are presented in this study. Since integrating and retaining the cargo (such as drugs, peptides and proteins) within drug carrier matrixes is achieved by matching the chemical or physical characteristics of the cargo with those of the carrier system, both structural and surface chemical control of the carrier is a prerequisite for a successful design of drug delivery systems. A number of features characteristic of mesoscopically ordered nanoporous silica materials facilitate their applicability as drug carrier matrixes. These include the high surface areas and pore volumes that enable the matrixes to host a large amount of cargo in combination with the regular structure and tuneable pore size, which in turn can provide a homogeneous distribution of a large amount of guest molecules in the matrix followed by a sustained release. Furthermore, different means of functionalizing the pore walls to provide anchoring points for the cargo molecules and enhance drug immobilization is investigated, and critically validated in terms of accessible amount surface groups. Moreover, if nanoparticulate mesoporous systems are employed, targeting capability can be added to the system and separated from the therapeutic functions via judicious design strategies. Therefore, a methodology based on hyperbranching surface polymerization of poly(ethylene imine) to selectively functionalize the outer particle surface is introduced. The telechelic nature combined with the dendritic structure of the introduced function flexibly allows for further modification of the particle surface, including tuning of the surface charge, enhancing suspension stability and/or attachment of biogenic molecules for targeting purposes and/or fluorescent dyes for tracing ability via standard bioconjugation reactions. Since the carrier physicochemical properties are the main determining factors that affect the pharmacokinetics and biodistribution of nanoparticles, these aspects are dealt with from a materials design point of view. The presented methodologies and results provide a rational basis for the design of multifunctional mesoporous drug delivery systems.
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Syntheses and Self‐Assembling Characteristics of Amphiphilic Star Diblock Copolymers. Strandman, Satu University of Helsinki, Faculty of Science, Department of Chemistry Defence on June 14th, 2008 Opponent: Professor Axel Müller, Bayreuth
New and emerging technologies based on polymeric materials have increased the demand for more advanced, tailor‐made polymers. The synthesis of well‐defined polymers and complex polymer architectures has been greatly facilitated due to the recent developments in controlled radical polymerization techniques, which has opened up new possibilities also in the design and preparation of functional nanostructures based on the supramolecular assembly. In nature, numerous structures of varying complexity can be produced upon the self‐assembling of individual molecules, such as lipids and proteins, by noncovalent interactions. Such molecules are often amphiphilic, i.e. they consist of both hydrophilic and hydrophobic moieties. Hence, an important class of synthetic polymers possessing similar self‐assembling characteristics is amphiphilic block copolymers. Amphiphilic block copolymers are composed of covalently linked hydrophilic and hydrophobic polymer chains, leading to characteristic solution properties. In block selective solvents, these polymers tend to associate to micelle‐like aggregates of various morphologies, which can transform from one to another when the solution conditions are changed. Depending on the morphology, the potential applications of the self‐assemblies lie in various fields of nanotechnology, for example, in the preparation of nanoparticles of different shapes or in templating of inorganic structures for nanomaterials, as well as in the encapsulation and delivery of compounds like drugs, dyes, anticorrosion agents, flavors, and fragrances. Amphiphilic block copolymers have also been investigated for industrial applications as rheology modifiers, emulsifiers, stabilizing agents of latexes or flocculants. The most commonly utilized amphiphilic block copolymers are linear ones, but recently the research has been directed towards more complex architectures, such as starlike or graft copolymers. Such polymers may exist in aqueous solutions in their self‐assembled form but also as single molecules, so called unimolecular micelles having a core‐shell structure even at low polymer concentrations, which makes them particularly attractive for solubilizing or binding hydrophobic compounds. The term ‘unimolecular micelle’ could in fact describe the structure of starlike amphiphilic block copolymers, which consist of linear block copolymers tethered to one point. Understanding the association processes is vital for controlling the self‐assembling behavior of various polymer architectures. Thus, the current work focuses on investigating the self‐assembling characteristics of well‐defined amphiphilic star polymers both experimentally and by computer simulations. The overall work can be divided in two sections: the one focusing on the synthesis of star polymers by macrocyclic initiators and the other concentrating on the characterisation of amphiphilic star block copolymers.
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Electrical Characterization of Organic Memories using Polarizable Nanoparticles
Baral, Jayanta Kumar Åbo Akademi University, Faculty of Mathematics and Natural Sciences, Department of Physics Defence on June 16th, 2009 Opponent: Manish Chhowalla, Rutgers, the state university of New Jersey
Organic memory is an emerging field of organic electronics. We have demonstrated a solution processable memory device where an organic nanocomposite solution comprising of a fullerene derivative [6,6]–phenyl C61 butyric acid methyl ester (PCBM)–based nanoclusters dispersed in an insulating polystyrene matrix sandwiched between two metal Aluminum electrodes. The devices show an initial high resistive (OFF) state which, upon reaching a certain threshold voltage, permanently switches to a low resistive (ON) state. The threshold voltage is found to be ~3.5V, independent of the sample thickness; a property ideal for printed electronics. After the threshold voltage, the ON state current follows by a negative differential resistance (NDR) state in the current voltage characteristics of the devices. We have clarified the role of the nanocomposite film, and shown that tunneling is the reason for current conduction for both before and after the threshold voltage [1]. When adding higher concentration of nanoparticles, they start to aggregate, and form spherical like aggregates, that changes the device behavior from a poor insulator (high resistance) until it forms a conducting pathway (ohmic behavior) [2]. To clarify the underlying principle of such device behaviour, we have suggested a mechanism, i.e. dielectric breakdown due to polarizable nanoparticles inside the insulating polymer matrix [2]. This mechanism of dielectric breakdown inside the insulating medium explains the origin for the threshold jump from low–conductivity OFF to high–conductivity ON state of the device. The effect of NDR behaviour in these devices could be explained by a tunneling process between the polarisable PCBM nanoclusters inside the insulating polymer PS matrix. We have been able to identify this model by establishing the correlation between the morphology and electrical performance of these memory devices. This, in turn, leads to the possibility of improving upon the device performance and achieve the goal of memory elements for printed electronics.
References:
1. J. K. Baral, H. S. Majumdar, A. Laiho, H. Jiang, E. I. Kauppinen, R. H. A. Ras, J. Ruokolainen, O. Ikkala, and R. Österbacka, Nanotechnology 19, (2008) 035203‐035209.
2. A. Laiho, H. S. Majumdar, J. K. Baral, F. Jansson, R. Österbacka, and O. Ikkala, Applied Physics Letter 93, (2008) 203309‐203311.
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3.2. Projects
3.2.1 Synthesis of functional inorganic particles and formulation of dispersions. Professor Jarl B. Rosenholm and Associate professor Mika Lindén
The main responsibilities within Project I can be summarized as follows: a) to synthesize functional nanoparticles, b) to surface functionalize the particles in desired ways, c) to prepare stable, printable dispersions of either nanoparticles synthesized in‐house or of commercially available particles. Both aqueous and organic dispersions are of interest, as different printing techniques have different requirements in terms of the solvent properties. During the year we have synthesized and thoroughly characterized a wide range of both porous and non‐porous nanoparticles, including SiO2, TiO2, SiO2/Fe3O4, and Mn2O3. All of these particles are available in particle sizes < 100 nm and as stable aqueous dispersions, which makes them ink‐jet printable. Different means of surface functionalization of the particles have been evaluated in order to optimize the dispersion stability at neutral pH. Furthermore, many of the particles have additional functionality, including superparamagnetic and fluorescent properties. Additionally, biologically active particles have been of special interest, where the particles contain active substances within the internal porosity, linked to the outer particle surface or both. Extensive electro‐kinetic characterization of non‐aqueous dispersions has also been carried out, again with special focus on dispersion stability. This is an important area of research, as non‐aqueous dispersions have been studied to a much lesser extent than aqueous dispersions, and relatively few literature reports can be found in this area. This is especially true for mixed‐solvent dispersions, which often are of key interest for ink‐formulation.
Thermodynamic Characterization of Lewis Functionalities on Dispersed Nano‐Materials Main funding: Academy of Finland Participating FunMat unit: DPC Björn Granqvist, Gun Hedström and Jarl B. Rosenholm On the molecular level it is customary to subdivide the interaction forces into: nondirectional purely dispersive (hydrophobic) forces as well as directional Lewis acid‐base forces and electrostatic forces. The first mentioned two groups are in the older literature related with the denotation van der Waals forces. In modern literature the directional dipolar forces are referred to as Lifshitz‐van der Waals interactions.
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The acid‐base concept is usually understood solely as a proton exchange (Brønsted activity), while the Lewis acid‐base concept has attracted less attention despite its great importance. The
Brønsted interaction is typical for aqueous solutions. The proton exchange produces charged species being involved in electrostatic interactions. The Lewis interaction, on the other hand, is characterized by the formation of an adduct between an acid (electron acceptor) and a base (electron donor). The Lewis interactions predominate in nonaqueous systems, such as oil dispersions, polymer matrices (composites) and gas reactions (e.g. catalysts). The aim of the project is to relate the thermodynamic parameters previously derived for the characterization of the Lewis type acid‐base site activities on functional solid surfaces with the properties determined with other instrumental methods. As a result of this characterization a semi‐empirical model will be developed which is based on the interaction parameters measured. The model enables a critical evaluation of the fundamental criteria upon which the published theories and the related experimental methods are founded. Collaboration: Ian Wark Research Institute, Australia Publication: B. Granqvist, G. Hedström and J.B. Rosenholm, “Acid‐Base Interaction of Probes at Silica Surface Microcalorimetry and Adsorption”. Journal of Colloid and Interface Science, in press Theoretical Modeling and Experimental Verification of Specific Ion‐Particle and Particle‐Particle Interactions Main funding: Academy of Finland Participating FunMat unit: DPC Per Dahlsten, Janne Puputti, Mats Granvik, Piotr Próchniak, Marek Kosmulski, Serge Durand‐Vidal and Jarl B. Rosenholm The interaction of ions with solid particles in aqueous electrolyte solutions leads to a space separation of electric charges at the particle/solution interfaces, known as the electrical double layer (EDL). The double layer is manifested in the electrokinetic phenomena. The structure and properties of the resulting EDL have long been a focus of intense scientific research. The main research has been devoted to dilute aqueous disperse systems using such experimental techniques as electrophoresis. However, a relatively new method to determine the particle electrokinetic properties based on the electro‐acoustic phenomena has recently been elaborated. Such measurements, due to their extended applicability, have gained an exceptional interest in recent years.
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One of the major problems of such electroacoustic measurements is the interpretation of the signal at high ionic strength and particle concentration. To the best of our knowledge, the signal due to the added supporting electrolyte is not accounted for properly but is considered as a background noise which should be simply subtracted from the total signal. Alternatively the problem is accepted as a limitation of the technique itself. However, we have shown that the salt contribution cannot be neglected when the signal arising from the colloidal particles is weak (e.g. in the vicinity of the isoelectric point) and a simple subtraction cannot be performed because the various contributions are not additive.
In order to improve the interpretation of the electroacoustic signal and to extract important information concerning the nature of the physicochemical processes at the particle surface (adsorption of monovalent or multivalent ions) a precise description of the salt contribution must be performed. We have therefore developed an analytical model which explicitly takes into account the relaxation effects and the hydrodynamic interactions between the various ionic species (individual ions and continuous liquid phase). The research has been supported by a prolonged collaboration with Prof. Marek Kosmulski, Dr. Serge Durand‐Vidal and Prof. P. Turq who are leading scientist in this field. As a proof of international appreciation of the research done Department of Physical Chemistry has been asked to host the International Electrokinetic Phenomena Conference in 2010. The outcome of the proposed joint multinational research would lay as an ideal example for the pre‐conference preparations. Collaboration: Technical University of Lublin and Pierre and Marie Curie University of Paris VI Publications: M. Kosmulski, P. Próchniak and J.B. Rosenholm, “The IEP of Carbonate‐Free Neodynium (III) Oxide”.Journal of Dispersion Science and Technology, 30, 1 (2009) M. Kosmulski, P. Prochniak and J.B. Rosenholm, “Electroacoustic Study of Titania at High Concentrations of 1‐2, 2‐1 and 2‐2 Electrolytes” Colloids and Surfaces, to appear (2009) M. Kosmulski, P. Próchniak and J.B. Rosenholm, “Electrokinetic Potentials of Al2O3 in concentrated Solutions of metal Sulfates”.Journal of Colloid and Interface Science, to appear (2009)
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Transport of Molecules and Ions in Porous Matrices Main funding: Graduate School of Materials Research Participating FunMat unit: DPC Espen Johannessen, Eddy W. Hansen and Jarl B. Rosenholm Most chemical analyses focus on equilibrium properties. However, the kinetic properties are of immense importance for the accurate modeling of chemical reactions and processes. Transport properties are most frequently related to capillarity and diffusion. In porous matrices, such as membranes and porous solids the characterization is restricted to indirect measurements. From the flow in and out of the porous matrix conclusions are drawn concerning the transport within the solid. Low‐field nuclear magnetic resonance provides a way to investigate the transport of molecules and ions in situ. The transport may further be used to interpret structural constraints for the diffusion and thereby define the internal structure. In this project models are developed for the diffusion of molecules and ions in porous matrices, such as wood and silica matrices. The tracheid structure is revealed for natural and petrified wood samples and for mesoporous silica matrices. Collaboration: University of Oslo, Norway Publication: E.H. Johannessen, E.W. Hansen and J.B. Rosenholm,”Diffusion Dependent Exchange Times Observed by PFG‐NMR”. Physical Chemistry Chemical Physics, submitted (2009) Molecular Understanding of Printability (MolPrint, ended 2007) Main funding: Finnish Funding Agency for Technology and Innovation (Tekes) Participating FunMat units: DPC, LPPC Carl‐Mikael Tåg, Hanna Koivula, Martti Toivakka and Jarl B. Rosenholm The key challenge originally placed on the MolPrint research partners was to utilize or to develop measurable quantities describing key professional terms, such as mottling. Then academic criteria derived from theoretical models could be used to produce commonly accepted measurable quality standards for paper manufacturers, but particularly for printing houses. The liquid spreading of a drop introduced during printing is usually modeled for an ideally smooth (Young) surface, with an average (homogeneous) chemical property. However, coated paper surfaces are both chemically and structurally heterogeneous. The coating color of the
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sample papers consist of a rich number of components, such as pigments, lattices and binders. Moreover the smoothness is dependent on physical treatment such as calendaring, but remains relatively rough. This feature must be considered when evaluating the wetting with liquids and inks. A comprehensive account on the equilibrium wetting properties of liquids on solid surfaces has been collected in a review. The work of adhesion (perpendicular interaction) between the ink and the paper surface represents the energy of immobilization (setting) of ink and the work of spreading (horizontal wetting) reflects the blotting tendency of an ink drop. Moreover, references to recent reports on the hydrophobic and polar (acid and base) properties of a range of paper qualities have been published. In these investigations the surface roughness has been corrected for and the chemical heterogeneity is evaluated as a chemical interaction of the surface. Collaboration: University of Joensuu, University of Jyväskylä, University of Oulu, University of Turku, University of Maine, Omya AG and Top Analytica Ltd Publications: J.B. Rosenholm, K.‐E. Peiponen and E. Gornov, “Materials Cohesion and Interaction Forces”. Advances in Colloid and Interface Science, 141, 48‐65 (2008) C.‐M. Tåg, M. Juuti, K.‐E. Peiponen and J.B. Rosenholm, ”Print Mottling: Solid‐Liquid Adhesion Related to Optical Appearance”, Colloids and Surfaces, A317, 658‐665 (2008)
H. Koivula, P. Gane, M. Toivakka, Influence of Ink Components on Print Rub, Nordic Pulp and Paper Research Journal, vol. 23(3):277‐284, 2008.
M. Juuti, H. Koivula, M. Toivakka, K.‐E.. Peiponen, A Diffractive Glossmeter For Local Gloss Measurements Of Papers And Prints, TAPPI Journal, vol. 7(4):27‐32, 2008. H. Koivula, J. Preston, P. Heard, M. Toivakka, Visualisation of the distribution of offset ink components printed onto coated paper, Colloids and Surfaces A: Physicochem. Eng. Aspects, 317: 557–567, 2008. K.‐E.. Peiponen, V. Kontturi, I. Niskanen, M. Juuti, J. Räty, H. Koivula, and M. Toivakka, On estimation of complex refractive index and colour of dry black and cyan offset inks by a multi‐function spectrophotometer, Measurement Science and Technology, vol. 19(11):115601, 2008. H. Koivula, D.W. Bousfield, M. Toivakka, Use of Confocal Laser Scanning Microscope and Computer Model to Understand Ink Cavitation and Filamentation s, In Proceedings of TAPPI Coating and Graphic Arts Conference, TAPPI Press, Atlanta GA, 2008.
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Molecular Understanding of Printability (MolPrint, ended 2007) Main funding: Finnish Funding Agency for Technology and Innovation (TEKES) Participating FunMat units: DPC, LPPC Mikael Järn, Carl‐Mikael Tåg, Joakim Järnström and Jarl B. Rosenholm The investigation of liquid spreading on solid surfaces is usually restricted to equilibrium wetting of nearly ideal, smooth polymers. Due to its complexity, less attention has been directed onto dynamic wetting of rough, chemically heterogeneous polar surfaces. The aim in this study is to apply the most common models developed for liquid spreading on pigment coated paper surfaces, for which the equilibrium surface energy components have been determined previously. Two models have been used to model the spreading of liquids on solid surfaces; the hydrodynamic and molecular kinetic model. The hydrodynamic model describes the energy dissipation as a result of viscous drag within the spreading droplet. The hydrodynamic model has showed the following asymptotic time‐dependence:
R t1/10 Θ t‐3/10 The molecular‐kinetic model by Blake and Haynes describes the three phase contact line movement as a stress modified molecular rate process involving adsorption of molecules of the advancing phase and concurrent desorption of molecules of the receding phase, respectively. The molecular kinetic model has showed the following asymptotic time‐dependence:
R t1/7 Θ t‐3/7 Publications: C.‐M. Tåg, M. Pykönen, J.B. Rosenholm and K. Backfolk, “Wettability of Model Fountain Solutions: The Influence of Topo‐Chemical and –Physical Properties of Offset Paper”.Journal of Colloid and Interface Science, 330, 428‐436 (2009) C.‐M. Tåg, M. Järn and J.B. Rosenholm,“Radial Spreading of Ink and Model Liquids on Heterogeneous Polar Surfaces” JAST submitted (2009) M. Järn, C.‐M. Tåg, J. Järnström and J.B. Rosenholm,“Spreading of Probe Liquids on Offset Papers” JAST submitted (2009) J. Järnström, M. Järn, C.‐M. Tåg, J. Peltonen and J.B. Rosenholm,”Spreading of Probe Liquids on Ink‐Jet Papers” JAST submitted (2009)
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Characterization and Control of Coating Layer Formation Main funding: KCL and Academy of Finland Participating FunMat unit: DPC Rasmus Eriksson, Juha Merta, Heikki Pajari and Jarl B. Rosenholm Industrially a most interesting question is what the result of interactions between particles in a coating slurry is at process conditions. The free formation of the coating layer is of particular importance for, e.g. curtain or spray coating processes. Sediment density and rheology has been utilized for the characterisation of the state of dispersions. However, the parameters for the modelling of these time dependent processes have generally been extracted from dilute model dispersion systems. In the present project the macroscopic effect of the interactions was determined at solids contents comparable to the industrially viable systems. This opens new perspectives to comprehensively investigate homo‐ and hetero‐coagulation and flocculation processes in concentrated dispersions. However, at high ionic strength the DLVO‐model fails to properly represent the experimental results. Therefore, a number of correction terms have been added to the model. Such contributions are: steric repulsion, Lewis acid‐base interaction and graininess (packing) of molecules (hydration) close to the surface. From an industrial point of view the extended DLVO‐theory, including steric interactions provides the ideal platform to investigate novel alternative coating processes such as curtain and spray coating (casting) processes. However, there is still a critical lack of proper understanding as concerns the interaction under real process conditions. No generally accepted theory covers this range. Another area of restricted research activity is the time‐dependent flux phenomena during dewatering and sedimentation i.e. transport of liquid out from consolidating matrices. The latter transport phenomena induces severe strain on the paper which may bending (warping of) the paper and induce cracks and heterogeneities in the coating layer. Collaboration: Helsinki University of Technology, University of Helsinki, VTT Publications: R. Eriksson, J. Merta and J.B. Rosenholm,”The Calcite‐Water Interface. II. Effect of Added Lattice Ions on the Charge Properties and Adsorption of Sodium Polyacrylate”. Journal of Colloid and Interface Science, 326, 396‐402 (2008) K. Backfolk, J. Peltonen, N. Triantafillopoulos, S. Lagerge and J.B. Rosenholm, “The Influence of Lubricating Agents on the Formation of a Film of a Styrene/Butadiene Latex”. Tribology Letters, 29, 57‐66 (2008) R. Eriksson, H. Pajari and J.B. Rosenholm, ”Shear Modulus of Colloidal Suspensions: Comparing Experiment with Theory”. Journal of Colloid and Interface Science, 332, 104‐112 (2009)
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Precipitation and Aggregation of Asphaltene in Organic Solvents Main funding: Neste and Finnish Funding Agency for Technology and Innovation (Tekes) Participating FunMat unit: DPC Bjarne Johansson, Rauno Friman and Jarl B. Rosenholm The total combinatory Gibbs free energy was successfully used to model the solubility of two purified asphaltenes in neat and mixed solvents and the precipitation of the asphaltenes from mixed solvents. Intrinsic viscosity and particle size both sensitively reflected the state of the asphaltenes in homogeneous solution and were used for determining the solubility parameters of the asphaltenes. Phase separation was clearly reflected by a dramatic increase in particle size. The interaction parameter was subdivided into enthalpy and entropy contributions. All parameters indicate an extensive association or secondary phase transition when the phase border was followed by simultaneously varying the temperature and the solubility parameter of the solvent. However, derived in two ways, the enthalpy and entropy contributions lead to conflicting results. These were evaluated on thermodynamic grounds. Collaboration: Neste Oil Corporation, Technology Centre Publications: J. Sadowska, B. Johansson, E. Johannessen, R. Friman, L. Broniarz‐Press and J.B. Rosenholm, “Characterization of Ozonated Vegetable Oils by Spectroscopic and Chromatographic Methods”. Chemistry and Physics of Lipids, 151, 85‐91 (2008) J.B. Rosenholm, “Solubility and Interaction Parameters as References for Solution Properties. I. Exceptional Mixing and Excess Functions” Advances in Colloid and Interface Sciences, 146, 31‐41 (2009) B. Johansson, R. Friman, H. Hakanpää‐Laitinen and J.B. Rosenholm, “Solubility and Interaction Parameters as References for Solution Properties. II. Precipitation and Aggregation of Asphaltene in Organic Solvents” Advances in Colloid and Interface Sciences, 147‐148, 132‐143 (2009) B. Johansson, R. Friman, P. Denifl and J.B. Rosenholm, “Influence of Polymers on the Emulsified Hydrocarbon Liquid and on the Surfactant Stabilized Toluene/Perfluoro‐octane Emulsions” Journal of Dispersion Science and Technology,30, 1 (2009)
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Development of paper for inkjet printing Main funding: Industry Participating FunMat units: LPCC, DPC Carl‐Mikael Tåg, Jarl B. Rosenholm, Jouko Peltonen Papers available on the market for high speed inkjet printing can roughly be divided into treated grades and high quality specialty paper grades. The treated grades usually perform well in 1‐color printing, printing of barcodes etc., but not so well in 4‐color printing. The very expensive high quality specialty papers perform well in 4‐color printing, but not always so well in printing bar codes. Currently the high quality specialty paper grades are mainly produced on small paper machines, due to limited production possibilities.
The aim of the Inkjet paper project is to develop paper grades which perform well in high speed inkjet printing, but with less complex structure and at a lower cost than current specialty inkjet papers. To do this, evaluation of what makes a paper good or bad for high speed inkjet printing will be carried out. Additionally the aim is to decrease the paper waviness which causes problems in the post handling process of the printed product.
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Clean Surfaces (ShinePro, ended 2007) Main funding: Finnish Funding Agency for Technology and Innovation (TEKES) Participating FunMat unit: DPC Per Dahlsten, Mikael Järn, Sami Areva, Mika Harju, Mari Raulio, Mirja Salkinoja‐Salonen, Tapio Mäntylä, Mika Lindén, Jouko Peltonen and Jarl B. Rosenholm There is a growing demand for self‐cleaning surfaces in a range of applications. The perhaps best known example is Wilkington self‐cleaning window glass, in which Titania is used as opto‐activated catalyst. Upon radiation in the visible or ultraviolet range optical energy is stored in the glass, which is capable to catalytically break down organic matter (dirt). Additionally, the stored energy makes the glass polar which facilitates the removal of the dirt by rain‐water. The aim of the project was to develop functional materials which could be activated with light or other external initiation. The dirt could be biological, organic or inorganic matter. A range of characterization techniques were utilized to follow the processing of the materials, to establish the cleaning mechanism and to demonstrate the cleaning action. Collaboration: Tampere University of Technology, Helsinki University of Technology, University of Helsinki Publications: J.B. Rosenholm and M. Lindén ”Controlled Synthesis and Processing of Ceramic Oxides – A Molecular Approach”, in ”Handbook of Surface and Colloid Chemistry”, (K.S. Birdi, Ed.), 3rd Ed., Ch.10, pp. 439‐497, CRC Press, Boca Raton, USA (2008). M. Harju, S. Areva, J.B. Rosenholm and T. Mäntylä, “Characterization of Water Exposed Plasma Sprayed Oxide Coating Materials Using XPS”. Applied Surface Science, 254, 5981‐5989 (2008) M. Harju, M. Järn, P. Dahlsten, J.B. Rosenholm and T. Mäntylä,”Influence of Long‐Term Aqueous Exposure on Surface Properties of Plasma Sprayed Oxides Al2O3, TiO2 and their Mixtures Al2O3‐13TiO2. Applied Surface Science, 254, 7272‐7279 (2008) M. Harju, M. Järn, P. Dahlsten, J.‐P. Nikkanen, J.B. Rosenholm and T. Mäntylä, ”Influence of Long‐Term Aqueous Exposure on Surface Properties of Plasma Sprayed Oxides Cr2O3 and Cr2O3‐ 25TiO2” Journal of Colloid and Interface Science, 326, 403‐410 (2008) M. Raulio, M. Järn, J. Ahola, J. Peltonen, J.B. Rosenholm, S. Tervakangas, J. Kolehmainen, T. Ruokolainen, P. Narko and M. Salkinoja‐Salonen, ”Microbe Repelling Coated Stainless Steel Analysed by Field Emission Scanning Electron Microscopy and Physicochemical Methods”Journal of Industrial Microbiology & Biotechnology, 35, 751‐760 (2008)
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Nanopatterned, Functional Surfaces by Design (NanoFused) Main funding: Academy of Finland Participating FunMat units: DPC, DPh Qian Xu, Jan‐Henrik Smått, Simon Sandén, Gytis Sliaužys, Ronald Österbacka, Mika Lindén Nanostructured porous inorganic and hybrid inorganic‐organic films are interesting materials for a wide range of applications. Within the framework of the NanoFused project novel thin films for selected applications, with special emphasis on optoelectronics, sensing, and cell attachment, where the film structure and function is a result of a molecular optimization and design process. Thus, the project covers all aspects from synthesis, characterization and functionalization, to application. Nanostructured films of semiconducting metal oxides, like TiO2 and ZnO, and their further functionalization by introduction of functional organic molecules serve as the basis for the material development. Non‐FunMat project partners: Biomaterials Center, Turku, Department of Chemistry, University of Joensuu Collaboration: Pierre and Marie Curie University, Paris, France, Vilnius University, Vilnius, Lithuania Publications: M. Järn, F.J. Brieler, M. Kuemmel, D. Grosso, M. Lindén, Wetting of Heterogeneous Nano‐patterned Inorganic Surfaces, Chem. Mater., 20 (2008) 1476–1483 M. Kuemmel, J.‐H. Smått, C. Boissière, L. Nicole, C. Sanchez, M. Lindén, D. Grosso, Hierarchical inorganic nanopatterning (INP) through direct easy block‐copolymer templating, J. Mater. Chem., (2009) DOI: 10.1039/b900518h S. Lepoutre, J.‐H. Smått, C. Laberty, H. Amenitsch, D. Grosso, M. Lindén, Detailed study of the pore‐filling processes during nanocasting of mesoporous films using SnO2/SiO2 as a model system, Microporous Mesoporous Mater., in press G. Sliaužys, G. Juška, K. Genevicius, G. Juška, J. H. Smått, M. Lindén, R. Österbacka, “TiO2‐PHT interface influence to charge carrier photo generation and recombination”, SPIE Proceedings 7142, 71420K (2008) Miikka Korhonen, ”TiO2‐pinnalle sidotun ruteeniftalosyaaniinin ja vanadiiniftalosyaniinin kaasuanturiominaisuuksien testaus” B.Sc. Thesis in Materials Chemistry, University of Joensuu, 2008.
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3g‐Nanotechnology based targeted drug delivery using the inner ear as a model target organ (NanoEar) Main funding: EU Participating FunMat unit: DPC Alain Duchanoy, Jessica Rosenholm, Boris Ufer, Mika Lindén The purpose of this project is to demonstrate the feasibility of targeted drug delivery using nanotechniques. Third generation multifunctional nanopaparticles (3G‐MFNP), which are biodegradable and traceable in‐vivo, are being developed for selective drug delivery. In parallel, other nanoparticles; lipid core nanocapsules, plasmids, dendrimers and hyperbranched polymers are also being developed. The proposed studies aim to assess the organ specific drug delivery potential of nanoparticles in the inner ear as an experimental target organ. The unique features of these nanoparticles include: biocompatibility, biodegradability, non‐toxicity, and EU‐approved material composition. The surface characteristics of these particles can be designed for selective targeting of specific tissues and cell types. In this project we will target sensory epithelium (inner ear hair cells), spiral ganlion cells and vascular tissue (stria vascularis) of the inner ear. The structure of the 3G‐MFNPs allows incorporation of a drug, gene or gene product as well as tracers, permitting in‐vivo verification and quantification of their release and distribution to target sites using Magnetic Resonance Imaging (MRI)‐based technology. The nano‐layers are developed for special body sites were bioactive electrodes are used for drug delivery. Collaboration: 25 partners from all over Europe Publications: J.M. Rosenholm, M. Lindén, Towards establishing structure–activity relationships for mesoporous silica in drug delivery applications, J. Controlled Release, 128 (2008) 157‐164. J.M. Rosenholm, A. Duchanoy, M. Lindén, Hyperbranching Surface Polymerization as a Tool for Preferential Functionalization of the Outer Surface of Mesoporous Silica, Chem. Mater. (2008) DOI: 10.1021/cm7021328 B. Ufer, J.M. Rosenholm, A. Duchanoy, L. Bergman, M. Lindén, Poly(ethylene imine) functionalized mesoporous silica nanoparticle for biological applications, Stud. Surf. Sci. Catal., 174 (2008) 353‐356. Jessica Rosenholm, PhD thesis, Modular Design of Mesoporous Silica Materials: Towards Multifunctional Drug Delivery Systems, DPC Alain Duchanoy, Master thesis: “Synthesis and Controlled Functionalization of (Mesoporous) Silica Particles”, DPC.
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Specific Targeting of Cancer Cells by Design ‐ Nanoparticles as Drug Delivery Systems Main funding: Tor, Joe och Pentti Borg foundation Participating FunMat units: DPC Jessica Rosenholm One of the big challenges of medicine today is to deliver drugs specifically to the defected cells. This is of special importance in cancer treatment as many of the pharmacological agents developed are harmful for non‐cancerous cells. The aim of the project is to develop and evaluate the use of nanoparticles as delivery systems to specifically target cancer cells. Due to the large surface area and the controllable surface functionality of the silica nanoparticles, they can be loaded with large amounts of drugs and coupled to molecules of choice for targeting purposes. Preliminary data show that particles linked to tracking molecules are specifically recognized and taken up by cancer cells as compared to particles lacking these tracking devices. A long term goal will be to evaluate the power of these particles to selectively target cancer cells in vivo in a mouse tumor model. Collaboration: Department of Biology, Åbo Akademi University Publication: J.M. Rosenholm, A. Meinander, E. Peuhu, R. Niemi, J.E. Eriksson, C. Sahlgren, M. Lindén, Targeting of porous hybrid silica nanoparticles to cancer cells, ACS Nano, in press
Synthesis and characterization of magnetic, gold‐functionalized nanoparticles for use in biological applications Main funding: Finnish Funding Agency for Technology and Innovation (Tekes) Participating FunMat unit: DPC Noémie Lloret, Lotta Bergman, Jessica Rosenholm, Mika Lindén Self‐assembly based synthesis of nanoparticles is a highly versatile route towards state‐of‐the‐art nanoengineering of functional materials. One of the most promising areas of nanoparticle research, both in terms of academic interest and possibilities for high‐value applications, is nanoparticle‐based systems for targeted delivery of biologically active agents. This is connected to the possibility of introducing multiple functions into one set of particles, which for example enables imaging (magnetic or optical activity), drug/gene incorporation, and introduction of targeting ligands (antibodies, proteins, etc.) into the same particles. The aim of the project is to synthesize magnetic particles surrounded by a silica core onto which gold nanoparticles are
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immobilized, but with a labile bond, so that the gold particles can be released by external stimuli. The final aim of the project is to use the magnetic silica particles as carriers for genes which are attached to the gold nanoparticles, and the gold particles together with the genes are then released locally in order to enhance the expression of the genes. Collaboration: Shanghai Jiao Ting University, Shanghai, China Publications:
Biologically guided nanoparticles – Targeting, safety and imaging technology (Biotarget) Funding: Academy of Finland Participating FunMat unit: DPC Lotta Bergman, Mika Lindén The development of nanotechnology is expected to lead to fast improvements in medical imaging and drug delivery. At the same time there are increasing concerns related to the safety issue. The aim of the project is to develop silica‐based, biologically targeted nanoparticles, which could be used in drug delivery or in the targeting of antigens to immunoresponsive cells (vaccination). Furthermore, novel imaging methods will be developed to analyze the fate of the particles in living cells and tissues. Of special interest is the evaluation of the biological safety of the particles and one of the aims of the project is to set criteria for nanoparticle toxicity in the immune system and at a single cell level. Collaboration: Department of Biochemistry, University of Turku, MediCity research laboratory, University of Turku, Computer Science, Åbo Akademi University Publication: L. Bergman, J. Rosenholm, A.‐B. Öst, A. Duchanoy, P. Kankaanpää, J. Heino, M. Lindén, On the Complexity of Electrostatic Suspension Stabilization of Functionalized Silica Nanoparticles for Biotargeting and Imaging Applications, J. Nanomater., (2008) doi:10.1155/2008/712514
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In situ studies of nucleation and growth of nanoparticles Main funding: EU Participating FunMat unit: DPC Mika Lindén Our long‐term activities related to the study of the mechanism of formation of mesoscopically ordered materials using in situ methods, especially synchrotron SAXS, has continued at the Austrian SAXS beam‐line at the synchrotron in Trieste, Italy. Currently, we have concentrated our work on the characterization of systems synthesized under acidic conditions, where either cationic or non‐ionic surfactants can be used as structure directing agents. As part of collaborative efforts, we have also used other complementary characterization methods, like Raman and NMR spectroscopy, which has allowed time‐resolved data to be collected related to both the chemical composition of the inorganic precursor and the structural evolution of the hybrid surfactant‐inorganic materials. In addition, detailed analysis of the nucleation and growth of ZnS has been carried out by stopped‐flow UV‐Vis spectroscopy. Collaboration: Austrian Academy of Sciences, Graz, Austria, Elettra Synchrotrone, Trieste, Italy, Pierre and Marie Curie University, Paris, France, University of Giessen, Germany
Publications: M. Tiemann, F. Marlow, J. Hartikainen, O. Weiss, M. Linden, Ripening Effects in ZnS Nano‐particle Growth, J. Phys. Chem. C., (2008) DOI: 10.1021/jp077729f N. Baccile, C.V. Teixeira, H. Amenitsch, F. Villain, M. Lindén, F. Babonneau, Time‐Resolved in Situ Raman and Small‐Angle X‐ray Diffraction Experiments: From Silica‐Precursor Hydrolysis to Development of Mesoscopic Order in SBA‐3 Surfactant‐Templated Silica, Chem. Mater. (2008) DOI: 10.1021/cm702128u M. Lindén, F. Babonneau, H. Amenitsch, N. Baccile, A. Riley, S. Tolbert, On the mechanism of formation of SBA‐1 and SBA‐3 as studied by in situ synchrotron XRD, proceeding of the 4th International FEZA Conference, 2‐6 September 2008, Paris, France, Studies in Surface Science and Catalysis, vol. 174 (B), pp. 103‐108.
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Versatile Metal Oxide Materials for Usage as Biomolecular Separation Media and Sensors Main funding: Academy of Finland, EU Participating FunMat unit: DPC Damien Bazin, Mika Lindén, Jan‐Henrik Smått The overall aims of the applied project are twofold: a) to synthesize, characterize, and functionalize novel non‐siliceous porous materials with a controlled morphology, and b) to study the performance of these materials in selected nanotechnological applications in order to establish rational structure‐activity and composition‐activity relationships. The chosen applications are namely phosphopeptide enrichment, phospholipid coatings for use in analyte‐membrane partitioning studies, and gas sensors. Especially within the fields of biomolecule separation and gas sensing, it is important to differentiate between the influences of the surface chemistry on the one hand and the pore structure and macromorphology on the other. When successful, the obtained results can serve as a platform for further rational material optimization cycles, rather than having to use a time consuming trial and error method. Collaboration: University of Vienna, Vienna, Austria Publications: M. Sturm, A. Leitner, J.‐H. Smått, M. Lindén, W. Lindner, Tin dioxide microspheres as a promising material for phosphopeptide enrichment prior to liquid chromatography‐(tandem) mass spectrometry analysis, Adv. Functional Mater., 18 (2008) 2381‐2389. J.‐H. Smått, N. Schüwer, M. Järn, W. Lindner, M. Lindén, Synthesis of micrometer sized mesoporous metal oxide spheres by nanocasting, Microporous Mesoporous Mater., (2008) doi:10.1016/ j.micromeso.2007.10.003
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3.2.2. Synthesis of organic particulate meso‐structures and core/shell capsules
The main objectives are to introduce functionality by design, controlled synthesis and by addition of tailor‐made additives to various polymer materials. In particularly, the correlation between material properties and the chemical structure of the constituents is of great interest. It has now become possible to introduce specific properties to polymeric materials in terms of morphology, topology, inter‐connected porosity and functionality through molecular engineering and/or processsing. Macromolecular engineering of complex molecular architectures such as in star, dendritic, hyperbranched and dendrigraft macromolecules may be produced for tailor made materials in various applications. In particularly, our aim is to focus on the following topics: ‐ To prepare novel core‐shell latexes (consisting of core that effectively encapsulates water and a hydrophobic shell), that has the capability of improving the optical properties of printed paper. In addition, we aim at introducing different functional moieties such as optical brighteners into the core shell latex. ‐ To successfully prepare various organic‐mineral hybride systems by using functional plastic nano‐particles (SMI(Styrene Maleic Imide) together with inorganic pigments such as kaolin and calcium carbonate. Thus, the inorganic pigment acts as a carrier for the obtained functional nano‐particles. Together they constitute a hybride system. Among other things we foresee the following benefits: enhanced dewatering, a flexible tool for the introduction of various functionalities to the pigment, improved smoothness and mechanical as well as strength properties of paper. ‐ To synthesis new polymers with complex architectures, which show a capability of self‐assembling in aqueous solutions or at an air‐water interface. Also, polymer‐containing hybrid and nanocomposite materials are of great interest. Synthesis of block and starblock copolymers, as well as polymer‐protected gold nano‐particles and nanoclay particles is conducted via controlled radical polymerization reactions (ATRP and RAFT). The polymers will also contain thermo‐responsive blocks which enables the manipulation of their assemblies in water. The assemblies may be utilized as carriers for various low molar mass substances and as nanoreactors, e.g. in future trials to construct nanosized metal wires and rods.
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Development of two component oxirane ester paint hardeners Main funding: Industry Participating FunMat units: LPT Minna Kaskinen, Ari Rosling and Carl‐Eric Wilén
The aim of this project is to gain knowledge of the characteristics and behavior of the two component oxirane ester paint hardener Duasolid 50. The current synthesis is studied and the product is developed. The main goal is to decrease the amount of free chlorendic acid in the product as well as to obtain a clear and colorless product with desired viscosity and hardening properties. The theoretical part deals mainly with paints and coatings in general, their composition and properties and the basic reactions behind the synthesis of Duasolid hardener. The raw materials used in the experimental part of this work are presented and the polymer definition according to REACH is reviewed. The last chapter goes shortly into the safety issues related to the laboratory work. In the experimental part three series of experimental hardeners were synthesized. Series 1 was a screening series of 14 different kinds of hardeners. Based on the viscosity and hardening properties of these synthesis products a 23 factorial design was planned in order to model the effect of the raw material composition on the viscosity of the hardener. Series 2 consists of the 11 syntheses of the factorial design plan. After the factorial design series additionally 4 complementary syntheses were carried out (Series 3). The physical and chemical properties of the experimental hardeners were determined and the hardeners’ performance in a paint system was studied. In comparison with current Duasolid hardeners, the new experimental products showed improved appearance. Almost all of the hardeners were clear and colorless. The amount of residual chlorendic acid in the products was also decreased significantly in certain syntheses. Regression models obtained from the factorial design can be utilized in designing experiments in the future. According to their appearance and drying properties, some of the hardeners might as such be ready for taking into production. Collaboration: Tikkurila Publications: Minna Kaskinen, Master thesis 2009
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Modified Maleimide Copolymers Main funding: Finnish Funding Agency for Technology and Innovation (Tekes) Participating FunMat unit: LPT Mia Koskinen, Carl‐Eric Wilén The reaction between maleic anhydride and amine produces maleimide and can easily be tailor‐made by using different primary amines to give functionality with designed properties. We have prepared aqueous nanodispersions of modified poly(styrene‐co‐maleimide) (SMI) and poly(octadecene‐alt‐maleimide) (OMI) from respective maleic anhydrides which both are commercially available polymers with high thermal stabilities. Modifications (see Scheme 1) were done by 4‐amino‐2,2,6,6,‐tetramethylpiperidine (TAD), L(+)‐aspartic acid (ASP) and fluorinated compounds. Finally we applied the modified maleimide nanoparticles on paper coating as speciality pigments.
Scheme 1: Modified maleimide copolymers where R1 is phenyl (SMI) or n‐hexadecyl (OMI) and R2 is TAD, ASP, TFEA or HFEA. We have successfully modified poly(styrene‐co‐maleimide) and poly(octadecene‐alt‐maleimide) copolymers by 4‐amino‐2,2,6,6,‐tetramethylpiperidine, L(+)‐aspartic acid and fluorinated compounds. These modified copolymers were applied in paper coating as auxiliary pigments. Full effect of the modifiers was not yet achieved and thus their concentration requires further optimization. The possibilities for modification of this versatile material are numerous. Collaboration: Ciba Speciality Chemicals, NV Topchim SA. Publications: Koskinen M., Wilén C.‐E., Synthesis of Poly(styrene‐co‐maleimide) and Poly(octadecene‐co‐maleimide) Nanoparticles and their Utilization in Paper Coating, Progress in Organic Coatings, accepted after minor revision
O O
H2CHC
R1
R2
N
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In vitro study on cell adhesion and signalling on degradable bioactive composite surfaces Main funding: Participating FunMat unit: LPT Eeva Orava and Ari Rosling The project has recently started and the aim of the research is to study cell adhesion, maturation and cell released biochemical molecules in contact with various polymeric implant surfaces. A key role in the success or failure of an implanted material or device is the level of influence that the material can exert over cell differentiation. Modulated surface properties are expected to affect the adhesion, differentiation and proliferation of a cell. Suitable chemical triggers or surface topography can determine the cell behaviour at the implant surface. The project will provide valuable information on the control of cell contact on different surfaces, which can be utilized in optimization of tissue engineering scaffolds.
Collaboration: Dr. Molly Stevens, Reader in Regenerative Medicine and Nanotechnology at Imperial Collage London, UK, where the practical work is performed. Publications:
Reactive in situ curing polymers for regenerative medicine Main funding: Industry Participating FunMat unit: LPT Peter Uppstu, Ari Rosling The purpose of this study is to develop a viscous in‐situ hardening, though biodegradable composite material for cartilage and bone defects. Polymer synthesis will be developed and subsequent curing reactions are studied by DSC. The rheological properties of the initial dough and the setting event will further be studied. Collaboration: Vivoxid Ltd, Finland Publications: Patent negotiations
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Hydrophilization of PLLA by blending with hydroxy‐modified poly(lactide‐co‐caprolactone). Porous scaffold preparation and their hydrolytical degradation in SBF. Main funding: Industry Participating FunMat unit: LPT Peter Uppstu, Eeva Orava, Ari Rosling Porous biodegradable matrices based on synthetic aliphatic polyesters are used in several medical applications. They are usually synthesized by ring opening polymerisation from corresponding cyclic diesters. Copolymers with different compositions and molecular weights can further be synthesized to achieve specific physical and chemical characteristics. Despite an ample amount of studies these materials often remains too hydrophobic being difficult to wet.
Our main objective is to prepare new tailored synthetic biodegradable polyester‐based homo‐ and copolymers especially with improved water adsorption properties. The ultimate scaffold structures are primarily intended for utilization either as temporary scaffolds or as carriers for bioactive molecules and bioactive inorganic materials.
Collaboration: Vivoxid LtD, Finland
Publications: Peter Uppstu, Master thesis 2008/2009
Patent issues are under negotiation
Rheology of Plastic Bonded Explosives Main funding: Industry Participating FunMat unit: LPT Jonas Lithén, Ari Rosling Plastic bonded explosives, (PBX), are high explosive compositions consisting of high explosive compounds, polymer‐based binders and additives. Their advantages are many e.g. more easily shaped when casting or compressed into complex shapes, as traditional explosives which usually requires hazardous melting. Ideally PBXs are low viscosity compositions enabling them to be poured into complex moulds with thin flow channels, like mines or grenades or booster caps. Low viscosity makes manufacturing in large scale less complex and enables more freedom in design and the composition does not need to be heated for viscous casting purposes. A big
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problem is to optimize explosive and flowing properties of PBX compositions. Increased solid explosive content increases explosive power but also increases sensitivity and viscosity. The research results are confidential. Collaboration: Forcit Ab, Finland Publications: Jonas Lithén, Master thesis 2009
Novel Biopolymer Coatings Main funding: Industry Participating FunMat unit: LPT Mohammad Kajeheian, Virpi Ääritalo, Nasir Zeeshan, Carl‐Eric Wilén, Ari Rosling
The purpose of food packaging is to preserve the quality and safety of the food as well as protect the product from physical and chemical, or biological damage. Polyethylene based materials have been the most frequently used packaging material by the food industry for over 50 years. Environmental concerns regarding use of non‐renewable oil resources and constantly growing waste streams have brought to attention alternative packaging materials from renewable sources capable of degrading in soil or during composting. Paperboard with a polymer coating may serve as packaging material for many products, not only food. The end application though strongly dictates the necessary needed material properties. In this project we develop packaging products based on biodegradable polymers from annually renewable sources. The polymer properties are tailored to meet requirements from processing, conversion and application point of views. The research results are confidential. Collaboration: Stora Enso, Finland Publications: Nasir Zeeshan, Master thesis 2008/2009
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Effects of Titanium dioxide /PCC masterbatch compositions on polyethylene films with regard to brightness and opacity. Main funding: Industry Participating FunMat unit: LPT Nasir Zeeshan and Ari Rosling
Precipitated calcium carbonate (PCC) is a useful additive for a wide range of plastic and elastomeric applications. Its crystalline shape and availability in variable particle size together with given hydrophobicity, provides enhancement of both polymer processing and subsequent physical properties. In this study filled polymer films were made by masterbatch extrusion. The masterbatches were prepared of commercial TiO2 which was partially substituted with experimental PCC filler. The films were tested especially for brightness, opacity and tensile properties. Filler distribution was studied with SEM. Collaboration: FP‐Pigments Oy, Finland Publications:
Green composite ‐ Environmentalfriendly and strong woodfibre reinforced starch composite. Main funding: STFI‐Packforsk AB, Sweden Participating FunMat unit: LPT
The aim of the present work is to develop environmentalfriendly structural composites based on woodfibres and starch from Nordic forestry and agriculture to substitute conventional synthetic composite materials from fossil hydrocarbons. Thus we forward an added value to the already existing production of both starch and cellulose.
Allylglycidylether‐modified starch with very low to high degree of substitution have been prepared and transformed into wood fibre reinforced composites. The high degree substitution matrix (HDS) was suited for composite preparation even with extremely high wood fibre contents. The less manipulated LDS matrix also exhibit good matrix‐fibre contact, though it produced composites with heterogeneous surface properties. The heterogeneity is also reflected in the LDS composites mechanical properties. With a partial enzymatic degradation
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the LDS matrix became more processable and the hygromechanical properties reached those of HDS. Microfribrillated cellulose were also tested for its reinforcing properties at 10 w% fibre loadings, showing similar tensile strength properties as those made of LDS and HDS with 40‐60 w% soft wood fibre loadings. However, the water adsorption was dramatically reduced.
Collaboration: KTH University, Sweden
Publications: Design of novel non‐halogenated flame retardants – combustion and polymer scientists join forces
Main funding: Academy of Finland and Ciba Specialty Chemicals Participating FunMat unit: LPT Melanie Aubert, Weronica Pawelec, Teija Tirri, Ronan Nicolas and Carl‐Eric Wilén Flame retardants have been used for centuries to reduce the flammability of materials; in the modern society inexpensive and effective brominated flame retardants are used in public transport (aircrafts, cars, trains, etc.), buildings/constructions and increasingly in housings for electrical/electronic equipment. However, a serious subset of these halogenated flame retardants are that new evidence show that they persist in our environment, bioaccumulate in the food chain and in our bodies, and may cause adverse effects in our children. This means that brominated flame retardants should be replaced with safer non‐halogenated alternatives. Recently, we have been able for the first time to identify azoalkanes as a novel and effective class of flame retardants for polyolefins. This observation has opened up new opportunities to design a number of non‐halogenated flame retardants based on diazene and related structures that are of both academic and industrial interest. Currently, we are exploring in detail the structure‐property relationships of various diazene derivatives and investigating their synergistic effects with conventional flame retardant systems. Our aim is to further make considerable advances in flame retardancy of polymeric materials by combining for the first time the skills and knowledge of combustion and polymer scientists. We believe that by better understanding the broader aspects of combustion and interaction of flame retardants therewith would enable us to design environmentally friendly flame retardant systems with enhanced performances. This effort will be based on interdisciplinary work and sound scientific principles to construct a novel toolbox that will be helpful in rendering any polymeric material fire retardant.
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Collaboration: Academy of Finland, Ciba Specialty Chemicals, Switzerland, and Process Chemistry Centre, Åbo Akademi University Publications: Roth Michael, Pfaendner Rudolf, Wilén Carl‐Eric, Aubert Melanie, Symmetric azo compounds in flame retardant compositions, PCT Int. Appl. (2008), 31 pp. WO 2008101845
Non‐halogenated fire retardants for two component polyurethane adhesive Main funding: Kiilto Oy Participating FunMat unit: LPT Bartosz Ziółkowski, Melanie Aubert and Carl‐Eric Wilén
This work has been focusing on finding suitable non‐halogenated flame retardants for polyurethane adhesives. Firstly, a broad literature study has been conducted in order to find suitable candidates and secondly novel flame retardants have been synthesized and admixed with the polyurethane precursors, i.e. polyol. The flame retardant testing of polyurethane plaques has been mainly conducted by cone calorimeter, whereby the rate of heat release, total heat release, amount of residue and average rate of heat emission values have been recorded and analyzed.
Collaboration: Process Chemistry Centre, Åbo Akademi University
Publications: Bartosz Ziółkowski, Master Thesis 2008
Porous versus novel compact Ziegler‐Natta catalyst particles and their fragmentation during early stages of bulk propylene polymerization Main funding: Borealis Polymers Participating FunMat unit: LPT Torvald Vestberg, Peter Denifl and Carl‐Eric Wilén It is well known that the nature of the catalyst support plays an important role in polymerization of olefins with Ziegler‐Natta and single site catalysts. According to most of the
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present literature, the physical strength and porosity of the support and final catalyst has a strong influence on both activity and polymer particle morphology. It was early suggested that it is the stress of the growing polymer that causes a progressive fragmentation of the catalyst particle. Galli et al stressed that a catalyst, used in propylene polymerization, should have high surface area and porosity as well as suitable mechanical strength in order to give high activity and good polymer powder morphology in an industrial process. It is also well recognized that fragmentation of the catalyst during the early stage of polymerization is decisive for the final polymer powder morphology. In several studies where SiO2 has been used as support it has been observed that the initial fragmentation of this support normally proceeds layer by layer. This has been shown with ZN catalyst for polyethylene and with single site catalysts for polypropylene and polyethylene. The strength and dimensions of the interconnecting network, in addition to the total pore volume, are important factors for controlling fragmentation and nascent polymerization with silica based catalysts. More recently, there have been reports in the literature of a catalyst that has neither measurable surface area nor porosity by BET analysis, but still has high activity and good powder morphology. The catalyst gives under mild conditions roughly the same activity in the early stage of polymerization as a porous catalyst with the same chemistry. The catalyst gives under conditions used in industrial processes good powder morphology. The behavior of this catalyst seems to conflict with what we know is a prerequisite of a good catalyst: high surface area and porosity. The target of this study is to investigate fragmentation of the catalyst, when polymerization is conducted under typical industrial process conditions, and to try to understand why the catalyst works so well despite its compactness. Collaboration: Borealis Polymers Publications: Valtola, Lauri; Hietala, Sami; Tenhu, Heikki; Denifl, Peter; Wilen, Carl‐Eric, “Association behavior and properties of copolymers of perfluorooctyl ethyl methacrylate and eicosanyl methacrylate”. Polymers for Advanced Technologies (2009), 20(3), 225‐234. Vestberg, Torvald; Denifl, Peter; Wilen, Carl‐Eric, “Porous versus novel compact Ziegler‐Natta catalyst particles and their fragmentation during the early stages of bulk propylene polymerization” Journal of Applied Polymer Science (2008), 110(4), 2021‐2029. Torvald Vestberg, Peter Denifl, Matt Parkinson, Carl‐Eric Wilén, “Effects of External Donors and Hydrogen Concentration on Oligomer Formation and Chain End Distribution in Propylene Polymerization with Ziegler‐Natta Catalysts” submitted to J. Polym. Sci. Chem Ed.
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Characterization and production of PEX pipes Main funding: KWH‐pipe Participating FunMat unit: LPT Anton Holappa and Carl‐Eric Wilen Pressurized polyethylene pipes have been used successfully for more than 50 years. In this work various production parameters have been optimized and various methods for fast characterisation of PEX pipes have been evaluated. Collaboration: Publications: Anton Holappa, Master Thesis 2008/2009
Polymerization of vegetable oils in diesel engines Main funding: Wärtsilä Finland Oy Power Plants Participating FunMat unit: LPT Markus Finne, Carl‐Erik Wilén, Juha‐Pekka Sundell and Niklas Haga The purpose of this research work was to investigate the causes why the polymerization of vegetable oils occurs, when these are used as fuel in diesel engines. It is shown that these oils can polymerize under specific conditions, especially in the fuel injection system. During this polymerization a firm product is produced, which can cause serious problems. To elucidate why these problems occur laboratory experiments was done on different vegetable oils. In laboratory surroundings the oils was reacted for a longer time under similar circumstances as in the fuel system, where these polymerization problems have appeared. These tests were performed in an Endeavor under slightly different conditions, whereupon the oils were analyzed accurately. The analyze instruments that were used were among others NMR and GC‐MS. In addition to this extensive tests on the oils were made in a DSC. Other things that were tested were for example the density of the oils from the different Endeavor runs. The solubility of a polymerization product from a power plant that was run on palmoil was also tested. These tests showed that the oils seem to undergo an oxypolymerization, which is a polymerization process that can occur when oxygen is presented. This reaction showed to be very slow and it can also be delayed by using antioxidants in the oils. Factors that affect this
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kind of polymerization are for example temperature, reaction time and also the degree of unsaturation of the oils.
Collaboration: Publications: Markus Finne, Master Thesis 2007/2008
Preparation of core‐shell latexes for paper coatings Main funding: Participating FunMat unit: LPT Mia Koskinen and Carl‐Eric Wilén
Core‐shell latexes, composed of a core covered by a shell, can be prepared by a two‐stage emulsion polymerization or seeded emulsion polymerization. The advantage of core‐shell latexes is their ability of having a composition of different monomers in core and shell, and thereby giving the particle tailor made properties for each application. Via core‐shell polymerization it is also possible to get otherwise incompatible monomers into one particle or to add functionality either into the core or shell.
A series of core‐shell latexes with a partially crosslinked hydrophilic polymer core and a hard hydrophobic shell of polystyrene were prepared in order to improve printability. Core‐shell latexes were prepared by a two‐stage emulsion polymerization by sequential addition of a monomer mixture of styrene, n‐butylacrylate and methacrylic acid using different crosslinkers to form the polymer core and styrene in the second stage to form the hard shell component. The prepared core‐shell latex particles were used as specialty plastic pigments for paper coating together with kaolin as the primary pigment. The runnability of paper coating formulation by either using a laboratory scale Helicoater or pilot scale JET‐coating machine was very good. The produced coated papers were printed on both sides employing a heat set web offset (HSWO) printer in order to study the quality of image reproduction in terms of print gloss, print mottle, print through, etc. To further improve latex particles a new polymerizable optical brightener 1‐[(4‐vinylphenoxy)methyl]‐4‐(2‐phenylethylenyl)benzene was inclueded during polymerization either into the core or shell. Overall the core‐shell latexes improved the print quality. Furthermore, the results demonstrate that by optimizing polymer composition one can affect optical properties of coated paper whereas the type of cross‐linker has a less pronounced influence on coated paper properties under investigation. By modifying paper coating it is possible to create a more favorable paper surface for functional printing or directly add functionality to it.
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Collaboration: Publications: Koskinen M, Carl‐Eric Wilén, “Preparation of core‐shell latexes for paper coatings “. Journal of Applied Polymer Science (2008), 110(4), 2021‐2029.
Controlled living graft polymerization of ionic monomers onto irradiated polymer films by Reversible Addition Fragmentation Chain‐Transfer Techniques Main funding: Participating FunMat unit: LPT Peter Holmlund and Carl‐Eric Wilén The irradiation modification processing of thin polymer films has been extensively used at our laboratory thanks to the availability of an Electron beam apparatus. The modification processes are uncontrolled when using normal radical polymerization techniques. Uncontrolled graft‐co‐polymerization of ionomeric chains causes poor quality of the produced films when the graft co‐polymers have a high degree of branching and high polymerdispersity. A proposed solution to this is the different controlled polymerization techniques: Atom Transfer Radical Polymerization (ATRP), Nitroxi Mediated Polymerisation (NMP) and Reversible Addition Fragmentation Chain‐Transfer (RAFT). The ATRP and NMP techniques have been investigated and published earlier by our laboratory, while RAFT technique is expected to bring added value to the controlled graft‐polymerization due to its simple application and robust character. Reversible Addition Fragmentation Chain‐Transfer polymerisation is a degenerative chain transfer process and is free radical in nature. It was first reported in 1996 by Rizzardo's group in Australia. Most RAFT agents contain thiocarbonyl‐thio groups, and it is the reaction of polymeric and other radicals with the C=S that leads to the formation of stabilized radical intermediates. In an ideal system, these stabilised radical intermediates do not undergo termination reactions, but instead reintroduce a radical capable of reinitiation or propagation with monomer, while they themselves reform their C=S bond. The cycle of addition to the C=S bond, followed by fragmentation of a radical, continues until all monomer is consumed.
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Our aim is to produce good quality ion exchange polymer films combining mechanical strength with high ion conductivities for a multitude of applications such as electrolytes for Polymer Electrolyte Membrane Fuel Cells and Direct Methanol Fuel Cells. Other possible applications include semiconductor use in transistors. Collaboration: Publications:
Modification of Polymeric Films – Ion‐ and Electron Conducting Materials Main funding: Participating FunMat units: LPT, DPh Carl‐Johan Wikman, Xe Xuehan, Carl‐Eric Wilén, Ronald Österbacka and Nikolai Kaihovirta The central themes during the year 2008 have been electron beam irradiated polymeric films as substrates for grafting, electrochromic polymeric materials and electron conducting and semi‐conducting polymeric materials. One main objective of studies in 2008 has been to gain a better understanding of the parameters governing the fabrication of ion‐conducting membranes by electron‐beam (EB) pre‐irradiation induced grafting. The prepared membranes have been utilized in the production of novel ion‐modulated membrane transistors (MEMFET; Finnish patent application 20070063) that allow the integration of various devices on the same substrate in an unprecedented way. Since, limiting the ion conductivity in a membrane to locally conducting regions may be necessary in order to minimize cross‐talk and interference with the surrounding atmosphere also methods to prepare patterned membranes have been included in this study. For optimal MEMFET transistor performance another prerequisite is that the contact between the ion‐conducting membrane and semiconducting layer is excellent. As a consequence of this, ion‐conducting membranes with locally tethered electrically conducting grafts of PANI have been also synthesized and characterized. More specifically, the aims have been:
1) To investigate various process parameters such as radiation dose, masking, sulfonation conditions, membrane thickness, temperature, concentration of monomers and solvents effect on the structure and properties of the produced ion‐conducting membranes.
2) To design and prepare suitable ion‐conducting membranes for fabrication of MEMFETs of different configurations.
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3) To prepare ion‐modulating membranes with tethered electron conducting PANI layer on top.
The year 2008 brought new views and ideas, and new aspects on their usability within FunMat. The work is continuing with new grafting methods and other possible routes to ion‐conducting membranes. Collaboration: Publications: Kaihovirta, N., Wikman, C‐J. Mäkelä T, Wilén, C‐E. R. Österbacka “Self‐supported ion conductive membrane based transistors“, Advanced Materials (2009), 21(24), 2520‐2523.
Optimal binder usage in coated paper (OPTIBIND) Main funding: Finnish Funding Agency for Technology and Innovation (Tekes) Participating FunMat units: LPT, LPCC Jonas Asplund, Mahdi Pahlevan, Carl‐Eric Wilén, Martti Toivakka
Today, the most commonly used pigment dispersants are based on polyacrylate salts that have been prepared by classical free radical polymerization. Although the classical free radical polymerization technique is characterized by many attractive features it also has some severe limitations, inherent to its mechanism. Especially, it is difficult to control molar masses and polydispersities as well as to introduce defined end‐groups, or to prepare special architectures such as block copolymers, star or comb‐like structures by classical free radical polymerization techniques. In recent years, it has been showed that these limitations can successfully be circumvented by using living (or controlled) free radical techniques such as NMRP (nitroxide‐mediated radical polymerization), ATRP (atom transfer radical polymerization) or RAFT (reversible addition‐fragmentation chain transfer polymerization). As a consequence of this and to be able to precisely control molecular weight and polydispersities as well as to have the option to prepare complex architectures we decided to prepare Na‐polyacrylate‐based dispersants by using RAFT process instead of utilizing classical free radical polymerization techniques.
Our future plan has been to conduct a series of polymerizations of AA by using the RAFT technique in order to obtain monodisperse polyacrylate salts with a range of molecular weights. The range of molecular weights was selected on the basis of the modeling results by University of Jyväskylä, Laboratory of Applied Chemistry. The polymerization products were
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then analyzed by using GPC, NMR, HPLC and by rheological measurements. After this, the dispersants was delivered to Åbo Akademi, Laboratory of Paper Coating and Converting for further testing. After the role of molecular weight of polyacrylate salts had been established the polymerization was expanded by introducing various functional monomers (e.g. in order to prepare block copolymers, branched polymers, etc.) that further altered the interaction between pigment‐dispersing agentbinder. The functional groups and polymer structures was prepared based on suggestions from steering group members, molecular modeling and literature.
Collaboration: University of Jyväskylä, Laboratory of Applied Chemistry and industry
Publications:
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1.2.3. New generation of dispersing agents Laboratory of Polymer Chemistry, University of Helsinki Petri Pulkkinen, Mikko Karesoja, Heikki Tenhu This work package concentrates on the syntheses of new water soluble/dispersible functional polymers which due to their amphiphilic (or oleophilic) character should find various applications as dispersing agents. A lot of emphasis has been given also to various nanoparticles (metals as gold, silver, and copper and also clays as montmorillonite and halloysite) grafted with polymers. Grafting the nanoparticles turn them dispersible in water or organic solvents. Dispersible metal particles are useful as such, e.g. because of their conductivity. Nanoclays, on the other hand may be used in coatings and also as carriers for various active substances. We have also successfully prepared several water‐dispersible conducting polymers, both p and n conducting ones.
Metal nanoparticles stabilized with polymers Main funding: Academy of Finland (FunMat) and ERANETproject RENACO Participating FunMat unit: LPC Petri Pulkkinen, Jun Shan, Jukka Niskanen
Gold, silver, and copper nanoparticles have been prepared which have been grafted/stabilized with polymers or low molar mass substances. Gold has been grafted mainly by a thermoresponsive polymer poly(N‐isopropylacylamide), PNIPAM or NIPAM oligomers. The main interest has been on the environmental effects on the optical properties of the particles, but also on the thermal behaviour of surface‐grafted polymer chains. Polymer‐grafted silver nanoparticles have been prepared to be used in antibacterial coatings (manuscript in preparation). The preparation of copper particles is most demanding: the particles need to be effectively protected against oxidation. Nanoscaled copper particles have sintering temperatures low enough to be sintered on paper. Sintering tests have been initiated in collaboration with other project groups. The development of printable conducting inks is crucial for printed intelligence technology. Many different kinds of printable inks have been studied in the literature, most commonly gold1, silver2 and copper3. Gold based inks are quite attractive due to the oxidative stability and easy handling of the formed particles. However, the high price of the gold source materials inhibits facile use of the derived inks in the industry, which aims for low printing costs. Selection
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of copper as the ink base can considerably lower the costs, but copper nanoparticles are prone for oxidation in air and the handling of the inks is therefore more difficult.
Typically, nanoparticle‐based inks are dissolved in a suitable solvent and inkjetted on the substrate, paper or glass for example. The substrate deposited nanoparticles are then sintered. During sintering, the protecting agent should be decomposed, allowing the particles to fuse together to form a continous conductive layer. The particles must be of narrow size distribution to facilitate ink‐based use.
Current Progress and Future Plans
Cooperation with FunMat ‐laboratories to research metallic nanoparticles and their possible uses in printed intelligence has been initiated. Gold, silver and copper nanoparticles have been synthesized, both protected similarly with butanethiol and dodecanethiol. Synthesized particles can be dispersed in various organic solvents, such as toluene, xylene and terpineol. Butanethiol protected particles exhibit low decomposition temperature for the protecting layer (120°C), which is reasonable for paper‐based appliciations. However, higher molar mass protecting agent would provide increased dispersing ability in solvents.
Preliminary inkjetting and sintering experiments have been made in collaboration with Åbo Akademi4. The resistance of the ink‐jet printed structures was measured in situ while sintering on a hot plate or with a light source. Other sintering techniques can also be used, such as oven, laser, microwave, electrical and plasma. A bulk resistivity of less than 25 μΩcm (i.e. a conductivity of 4∙104 S/cm) was achieved by exposing the inkjet printed structures to an infrared lamp5.
The in‐situ measured resistance revealed the percolation process of the nanoparticles during sintering. The conductivity of the sintered gold nanoparticles was, however, limited by the formation of cracks due to the large volume reduction during the sublimation of the alkanethiols (and the bad adhesion to the substrate). The cracks and the coffee stain effect were smaller on the rougher and slightly porous paper substrate than on glass and plastics5.
The nanoparticles were also investigated before and/or after sintering by thermogravimetric analysis, wide angle X‐ray scattering, optical microscopy, atomic force microscopy, absorption spectrometry, X‐ray photoelectron spectroscopy and Kelvin probe measurement5.
Butanethiol protected silver particles were also preliminarily studied. Unfortunately the particles precipitated and were impossible to redisperse. Silver particles protected with a mixture of dodecanethiol and butanethiol were synthesized. With this material there seem to be drying issues: if the material is dried or precipitated during the synthesis procedure, the particles cannot be redispersed. This may be due to the evaporation of the butanethiol from the system.
To counter the limitations of butanethiol, synthesis of a novel calixarene based protecting agent has been initiated. Once ready, the calixarene protected particles will be extensively studied for printed intelligence purposes.
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References
(1) M. Brust, M. Walker, D. Bethell, D. J. Schiffrin , R. Whyman , J. Chem. Soc. Chem. Commun. , 1994, 801‐802 (2) H. H. Lee, K. S. Chou, K.C. Huang, Nanotechnology, 2005, 16, 2436‐2441 (3) J. Shan, P. Pulkkinen, U. Vainio, J. Maijala , J. Merta, H. Jiang, R. Serimaa, E. Kauppinen , H. Tenhu , J. Mater. Chem, 2008, 18, 3200‐3208 (4) D. Huang, F. Liao, S. Molesa, D. Redinger, V. Subramanian, J. Elechtrochem. Soc., 2003, 150, G412‐G417 (5) Daniel Tobjörk, Petri Pulkkinen, F.S. Pettersson, Tapio Mäkelä, Heikki Tenhu and Ronald Österbacka, Graduate School of Materials Research Spring Seminar, 2009. Collaboration: Helsinki University of Technology, ÅA, several European laboratories Publications: Maijala, Juha; Merta, Juha; Shan, Jun; Tenhu, Heikki: Novel particles and method of producing the same ,PCT Int. Appl. (2009), WO 2009040479 A1 20090402 Shan, Jun; Zhao, Yiming; Granqvist, Niko; Tenhu, Heikki: Thermoresponsive Properties of N‐Isopropylacrylamide Oligomer Brushes Grafted to Gold Nanoparticles: Effects of Molar Mass and Gold Core Size ,Macromolecules (Washington, DC, United States) (2009), 42(7), 2696‐2701. Pulkkinen, Petri; Shan, Jun; Leppänen, Kirsi; Kansakoski, Ari; Laiho, Ari; Järn, Mikael; Tenhu, Heikki: Poly(ethylene imine) and Tetraethylenepentamine as Protecting Agents for Metallic Copper Nanoparticles, ACS Applied Materials & Interfaces (2009), 1(2), 519‐525. Shan, Jun; Pulkkinen, Petri; Vainio, Ulla; Maijala, Juha; Merta, Juha; Jiang, Hua; Serimaa, Ritva; Kauppinen, Esko; Tenhu, Heikki: Synthesis and characterization of copper sulfide nano‐crystallites with low sintering temperatures, Journal of Materials Chemistry (2008), 18(27), 3200‐3208. Lay‐Theng Lee, Heikki Tenhu et al., Tuning the structure of thermosensitive gold nanoparticle monolayers, The Journal of Physical Chemistry B, in press Bruno Van Mele, Heikki Tenhu et al., Demixing and Remixing Kinetics in Aqueous Dispersions of Poly(N‐isopropylacrylamide) (PNIPAM) Brushes Bound to Gold Nanoparticles Studied by Means of Modulated Temperature Differential Scanning Calorimetry, Macromolecules, in press
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Grafting of nanoclays Main funding: Academy of Finland (FunMat) and EU project MUST Participating FunMat units: LPC, DPC Mikko Karesoja, Jukka Niskanen Nanosized montmorillonite has been grafted with an amorphous polymer by ATRP reactions in order to prepare MMT containing composites with good film forming properties. Also other clays, as halloysite and sepiolite have been tested. At present, clays are also grafted with water‐soluble polymers to be used as carriers in anticorrosive coatings. Surface derivatized mesoporous particles obtained from other project groups are being prepared at the moment. Modification of silica surfaces can be performed via surface initiated atom transfer radical polymerisation (ATRP) technique. By this method it is possible to bound polymers covalently on different silica surfaces like layered silicates (montmorillonite clay) or silica particles. The ATRP‐initiator can be bound on the silanol groups on the silica surface via silylation reactions. These initiator modified particles can be further use to initiate polymerisation reactions. ATRP polymerisation technique is very versatile method to graft different surfaces and by this method very homogenous surface modification can be achieved. Surface modification of particles is in many cases crucial. The idea in the modification is to make particles more compatible with its surroundings. For example in clay composites the good compatibility with the matrix polymer is essential for homogenous mixing of the clay with matrix. In bio applications the silica surface can be modified so that the particles are well biocompatible. In composite applications the good dispersability and the exfoliation of the silicate layers are essential for achieving good optical, barrier, dielectric, flame retardant, and barrier properties. The aim of the work has been to covalently bound ATRP initiator on the internal and external surface of montmorillonite by silylation rections. The clay modified with the ATRP initiator has been used to initialise the polymerisation of butyl acrylate and methyl methacrylate, to achieve exfoliated clay. The polymer modified clay was mixed with matrix polymer poly(BuA‐co‐MMA) in solution and films were casted. The exfoliation of clay was studied by small angle x‐ray scattering (SAXS) and transmission electron microscope (TEM). SAXS and TEM both suggested that exfoliated structure was formed when polymerisation of BuA and MMA was performed in dimethylsulfoxide (DMSO) solution. The mechanical properties of composite films were studied by dynamic mechanical thermal analysis DMTA. DMTA results showed that the glass transition temperature of composites remained constant even though the clay content was increased in the composites. This
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indicates that the modification of the clay leads very good compatibility with the matrix polymer. In the stress strain measurements the stiffness of the material was increased when the clay content was increased. Also comparison between composite films, where the filler was unmodified clay and composite films with polymer modified clay was done (fig. 1). This comparison showed clearly that the exfoliated polymer modified clay improves the mechanical properties significantly and the unmodified pure clay had no significant effect on mechanical properties.
0 50 100 150 200 250 300 350 4000,0
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a)
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2% pure clay 5% pure clay 2% modified clay 5% modified clay
Figure 1. Stress‐strain comparison of composites (unmodified clay vs. polymer modified clay)
This study has been published in the Journal of Polymer Science 2009. The aim of the study is to modify mesoporous silica particles by using surface initiated ATRP polymerisation like in the case of montmorillonite. The idea of the modification is to make bio compatible silica particles where the surrounding layer is thermoresponsive. Silica particles aim to be drug carriers in medical applications. Laboratory of Physical Chemistry in Åbo Akademi is providing mesoporous silica particles in this study. They have extensively studied preparation and modification of mesoporous silica. Collaboration: Åbo Akademi University, 20 partners in the MUST project Publications: Karesoja, Mikko; Jokinen, Harri; Karjalainen, Erno; Pulkkinen, Petri; Torkkeli, Mika; Soininen, Antti; Ruokolainen, Janne; Tenhu, Heikki: Grafting of montmorillonite nano‐clay with butyl acrylate and methyl methacrylate by atom transfer radical polymerization: Blends with poly(BuA‐co‐MMA), Journal of Polymer Science, Part A: Polymer Chemistry (2009), 47(12), 3086‐3097.
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Amphiphilic star polymers Main funding: Academy of Finland, NANO, ESPOM, DAAD Participating FunMat unit: LPC Anu Koponen, Katriina Kalliomäki, Satu Strandman, Felix Plamper, Mikko Mänttäri, Anna Zarembo, Sergey Larin Amphiphilic star polymers with varying numbers of arms are prepared, where the inner part is hydrophobic and the outer shell is hydrophilic. Monomers are chosen in a way that the hydrophobic core is either glassy or rubbery, and the hydrophile is either polyacrylic acid or PNIPAM. The properties of the stars are compared with those of corresponding linear polymers. Polymers have been shown to have interesting associating properties in water. Some of the polymers are tested as carriers for various active agents (as wood preservatives or fullene C60, the latter one to be used in non‐linear optics. The first PhD thesis on this topic was by Satu Strandman who defended her thesis in 14.6.2008. Coarse‐grained modeling of stars and dendrimers (and their complexes) in aqueous surroundings have been conducted by Anna Zarembo and Sergey Larin in collaboration with Professor Anatoly Darinskii (Institute of Macromolecular Compounds, RAS, St Petersburg). Also miktoarm stars have been prepared. These are polymers containing two types of arms: polyethylene oxide and poly(dimethylaminoethyl methacrylate), PDMAEMA. Under certain conditions PDMAEMA shows both LCST and UCST behaviour (i.e. it phase separates from water either with increasing or decreasing temperature. The micellization may be manipulated by either temperature or light. This project continues with syntheses of “dumbbell” polymers. Collaboration: University of Bayreuth, Helsinki University of Technology, VTT, KCL, Institute of Macromolecular Compounds, RAS, St Petersburg Publications: Plamper, Felix, Tenhu Heikki et al: e‐Micellization: Electrochemical, Reversible Switching of Polymer Aggregation, Macromolecules, submitted Plamper, Felix A.; McKee, Jason R.; Laukkanen, Antti; Nykänen, Antti; Walther, Andreas; Ruokolainen, Janne; Aseyev, Vladimir; Tenhu, Heikki: Miktoarm stars of poly(ethylene oxide) and poly(dimethylaminoethyl methacrylate): manipulation of micellization by temperature and light, Soft Matter (2009), 5(9), 1812‐1821.
Hietala, Sami; Strandman, Satu; Järvi, Paula; Torkkeli, Mika; Jankova, Katja; Hvilsted, Soren; Tenhu, Heikki: Rheological Properties of Associative Star Polymers in Aqueous Solutions: Effect of Hydrophobe Length and Polymer Topology, Macromolecules (2009), 42(5), 1726‐1732.
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Strandman, Satu; Zarembo, Anna; Darinskii, Anatoly A.; Laurinmäki, Pasi; Butcher, Sarah J.; Vuorimaa, Elina; Lemmetyinen, Helge; Tenhu, Heikki: Effect of the Number of Arms on the Association of Amphiphilic Star Block Copolymers ,Macromolecules (2008), 41(22), 8855‐8864.
Larin, Sergey; Lyulin, Sergey; Lyulin, Alexey; Darinskii, Anatoly: Computer simulations of interpolyelectrolyte complexes formed by star‐like polymers and linear polyelectrolytes, Macro‐ molecular Symposia (2009), 278(Molecular Order and Mobility in Polymer Systems), 40‐47. Lyulin, Sergey; Karatasos, Kostas; Darinskii, Anatolij; Larin, Sergey; Lyulin, Alexey: Structural effects in overcharging in complexes of hyperbranched polymers with linear polyelectrolytes, Soft Matter (2008), 4(3), 453‐457.
Thermoresponsive polymers Main funding: ESPOM, Academy of Finland Participating FunMat unit: LPC Markus Nuopponen, Antti Laukkanen This project partially overlaps with the previous ones because we have used thermoresponsive PNIPAM in several applications. However, several other polymers based on PNIPAM or polyvinylcaprolactam have been prepared as well. The focus has been on one hand on the self‐assembling properties of aqueous polymers, and on the other, on RAFT polymerization reactions. One of the important findings to be mentioned here is that it has been possible to control not only molar mass but also stereoregularity of PNIPAM. This is interesting, because isotactic PNIPAM is not water soluble. Markus Nuopponen defended his PhD on this topic on 9.5.2008. Collaboration: Department of Pharmacy, University of Helsinki, Helsinki University of Technology, University of Oslo, University of Montreal Publications: Vihola, Henna; Laukkanen, Antti; Tenhu, Heikki; Hirvonen, Jouni: Drug release characteristics of physically cross‐linked thermosensitive poly(N‐vinylcaprolactam) hydrogel particles, Journal of Pharmaceutical Sciences (2008), 97(11), 4783‐4793.
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Nuopponen, Markus; Kalliomäki, Katriina; Aseyev, Vladimir; Tenhu, Heikki: Spontaneous and Thermally Induced Self‐Organization of A‐B‐A Stereoblock Polymers of N‐Isopropylacrylamide in Aqueous Solutions, Macromolecules (2008), 41(13), 4881‐4886. Nykänen, Antti; Nuopponen, Markus; Hiekkataipale, Panu; Hirvonen, Sami‐Pekka; Soininen, Antti; Tenhu, Heikki; Ikkala, Olli; Mezzenga, Raffaele; Ruokolainen, Janne: Direct Imaging of Nanoscopic Plastic Deformation below Bulk Tg and Chain Stretching in Temperature‐Responsive Block Copolymer Hydrogels by Cryo‐TEM, Macromolecules (2008), 41(9), 3243‐3249. Hietala, Sami; Nuopponen, Markus; Kalliomäki, Katriina; Tenhu, Heikki: Thermoassociating Poly(N‐isopropylacrylamide) A‐B‐A Stereoblock Copolymers, Macromolecules (2008), 41(7), 2627‐2631. Kjoniksen, Anna‐Lena; Laukkanen, Antti; Tenhu, Heikki; Nyström, Bo: Anomalous turbidity, dynamical, and rheological properties in aqueous mixtures of a thermoresponsive PVCL‐g‐C11EO42 copolymer and an anionic surfactant, Colloids and Surfaces, A: Physicochemical and Engineering Aspects (2008), 316(1‐3), 159‐170. Laukkanen, Antti; Tenhu, Heikki: Thermally responsive polymers with amphiphilic grafts: smart polymers by macromonomer technique. From Smart Polymers: Applications in Biotechnology and Biomedicine (2nd Edition) Ed. Galaev, Igor; Mattiasson, Bo (2008), 115‐136. CRC Press.
Fluorinated polymeric surfactants Main funding: Industry Participating FunMat unit: LPC Lauri Valtola, Sami Hietala Several of low molar mass fluorinated surfactants used in chemical industries are toxic, and especially from the REACH view point, their replacement with polymeric ones is beneficial. Using ATRP technique, several new fluorinated and semifluorinated polymers have been synthesized. Collaboration: Publication: Valtola, Lauri; Hietala, Sami; Tenhu, Heikki; Denifl, Peter; Wilen, Carl‐Eric: Association behavior and properties of copolymers of perfluorooctyl ethyl methacrylate and eicosanyl methacrylate, Polymers for Advanced Technologies (2009), 20(3), 225‐234.
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Valtola, Lauri; Koponen Anu; Karesoja Mikko; Hietala Sami; Laukkanen Antti, Tenhu Heikki, Denifl Peter: Tailored surface properties of semi‐fluorinated block copolymers by electospinning, Polymer (2009), 50, 3103‐3110.
Properties of aqueous polymer solutions and dispersions This wide group of topics reflects the various aspect and areas of interest in the laboratory. Main funding: Acedemy of Finland, Finnish Funding Agency for Technology and Innovation (Tekes), CIMO Participating FunMat unit: LPC Collaboration: University of Turku, Institute of Macromolecular Compounds (St Petersburg) Publications: Huhtinen, Petri; Kivelä, Mirja; Soukka, Tero; Tenhu, Heikki; Lövgren, Timo; Harma, Harri: Preparation, characterisation and application of europium(III) chelate‐dyed polystyrene‐acrylic acid nanoparticle labels, Analytica Chimica Acta (2008), 630(2), 211‐216.
Tarabukina, E. B.; Krasnov, I. L.; Tarasova, E. V.; Ratnikova, O. V.; Melenevskaya, E. Yu.; Filippov, A. P.; Laukkanen, A.; Aseev, V. O.; Tenhu, H.: The effect of the centrifugal force on the molecular characteristics of polyvinylcaprolactam complexes with fullerene C60, Vysoko‐ molekulyarnye Soedineniya, Seriya A i Seriya B (2008), 50(2), 315‐323. Krasnou, Illia; Tarabukina, Elena; Melenevskaya, Elena; Filippov, Alexander; Aseyev, Vladimir; Hietala, Sami; Tenhu, Heikki: Rheological Behavior of Poly(vinylpyrrolidone)/Fullerene C60 Complexes in Aqueous Medium, Journal of Macromolecular Science, Part B: Physics (2008), 47(3), 500‐510. Andersson, Toni; Sumela, Miika; Khriachtchev, Leonid; Räsänen, Markku; Aseyev, Vladimir; Tenhu, Heikki: Solution properties of an aqueous poly(methacryl oxyethyl trimethylammonium chloride) and its poly(oxyethylene) grafted analog, Journal of Polymer Science, Part B: Polymer Physics (2008), 46(6), 547‐557. Matilainen, Laura; Maunu, Sirkka Liisa; Pajander, Jari; Auriola, Seppo; Jääskeläinen, Ilpo; Larsen, Kim Lambertsen; Järvinen, Tomi; Jarho, Pekka: The stability and dissolution properties of solid glucagon/γ‐cyclodextrin powder, European Journal of Pharmaceutical Sciences (2009), 36(4‐5), 412‐420.
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Water dispersible conducting polymers Main funding: Finnish Funding Agency for Technology and Innovation (Tekes) Participating FunMat unit: LPC Sami‐Pekka Hirvonen This project is a part of a larger one, “Organic solar cell” coordinated by Professor Helge Lemmetyinen. The aim is to prepare environmentally friendly aqueous dispersions of conducting polymers to be used as conducting layers in photovoltaic cells. The work started by the preparation of water‐dispersible polyaniline derivatives, for which a patent is filed together with Finnish company Panipol. Polyaniline turned out not to be the polymer of choice, and the polymers being prepared at the moment are derivatives of poly(benzimidazol‐benzofenantroline) Water dispersibility in both cases is obtained by binding short polyethyleneoxide chains to the rigid polymers. Collaboration: Åbo Akademi University, University of Turku, industry Publication: Tenhu, Heikki; Hirvonen, Sami‐Pekka; Hartikainen, Juha: Conductive polymer compositions and method for the production thereof, PCT Int. Appl. (2008), WO 2008006945 A1 20080117.
Rheological characterization of materials Main funding: University of Helsinki
Participating FunMat unit: LPC Sami Hietala Publications: Hoppu, Pekka; Hietala, Sami; Schantz, Staffan; Juppo, Anne Mari: Rheology and molecular mobility of amorphous blends of citric acid and paracetamol, European Journal of Pharma‐ceutics and Biopharmaceutics (2009), 71(1), 55‐63. Raula, Janne; Thielmann, Frank; Kansikas, Jarno; Hietala, Sami; Annala, Minna; Seppälä, Jukka; Lähde, Anna; Kauppinen, Esko I. : Investigations on the Humidity‐Induced Transformations of Salbutamol Sulphate Particles Coated with L‐Leucine, Pharmaceutical Research (2008), 25(10), 2250‐2261.
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Lintinen, Kalle; Efimov, Alexander; Hietala, Sami; Nagao, Shijo; Jalkanen, Pasi; Tkachenko, Nikolai; Lemmetyinen, Helge: Cationic photopolymerization of liquid fullerene derivative under visible light, Journal of Polymer Science, Part A: Polymer Chemistry (2008), 46(15), 5194‐5201.
Wood chemistry Main funding: Industry and the Forest Cluster
Participating FunMat unit: LPC Sirkka‐Liisa Maunu, Tiina Liitiä, Tommi Virtanen, Pirita Uschanof Main themes in this research have been the structure of wood and changes during heat treatment. Various cellulose derivatives are being prepared. Collaboration: KCL, VTT Publications: Maunu, Sirkka Liisa : 13C CPMAS NMR studies of wood, cellulose fibers, and derivatives Characterization of Lignocellulosic Materials, edited by Hu, Thomas Q, (2008), 227‐248. Uschanov, Pirita; Heiskanen, Nina; Mononen, Pekka; Maunu, Sirkka Liisa; Koskimies, Salme: Synthesis and characterization of tall oil fatty acids‐based alkyd resins and alkyd‐acrylate copolymers, Progress in Organic Coatings (2008) 63(1), 92‐99. Virtanen, Tommi; Maunu, Sirkka Liisa; Tamminen, Tarja; Hortling, Bo; Liitia, Tiina: Changes in fiber ultrastructure during various kraft pulping conditions evaluated by 13C CPMAS NMR spectroscopy, Carbohydrate Polymers (2008), 73(1), 156‐163. Recently started projects Szymon Wiktorowicz synthesizes calixarene derivatives. The aim is to lock the conical conformation and to use the calixarenes as building blocks for new polymers. (Partially funded by FunMat) Erno Karjalainen polymerizes ionic liquids, IL, and synthesizes block copolymers where one block is PIL, and the other is a water soluble (responsive) polymer. (Funded by Tekes 2010‐)
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1.2.4. Substrate activity and compatibility for functional materials Laboratory of Paper Coating and Converting (LPCC)
The requirements that potential future smart and intelligent paper applications set for natural fiber‐based substrates are different from, and often more demanding, when compared to traditional publication papers. A successful production of a functional device by e.g. a printing process requires a stable surface that is ultra‐smooth, has appropriate adhesion properties, is chemically inert, have controlled wettability and barrier properties and acceptable mechanical properties. These requirements and their combinations are not inherent properties of paper and cannot be met with currently available paper grades. The objective of this project is to understand the requirements and control the compatibility between the various materials that when combined result in new value‐added functional concepts. Three main areas of research are envisioned: (a) modification and control of the properties of natural fiber‐based substrates in order to make them compatible with the added functionality concepts, (b) clarification and control of the processability of functional (raw) materials as defined by the surface treatment, coating or printing processes that are used to assemble the novel functional surfaces, sensors and devices, and (c) embedding of new functionality into or onto the substrate. An important goal is to understand setting mechanisms of novel inks that are used for printed functionality. Understanding of mechanisms and interactions between ink components and solvents and print substrates is needed for successful printability and utilization of fiber‐based products for printed functionality. Detailed and versatile characterization of surface chemical and topographical properties of the studied surfaces and interfaces is an important part of the research. One approach to improve substrate compatibility is to adapt techniques already in use for traditional surface treatment, e.g., pigment coating, surface sizing and calendering. In addition, nanoparticle‐stabilized dispersions/emulsions will be utilized as compatibilizers and adhesion promoters of substrate coatings. One of the specific goals is to understand the prerequisites for incorporating biofunctional coatings and sensor elements to printable electronic devices. The instrumentation has been actively upgraded with new test printers (offset, gravure, flexo, inkjet) and coaters (reverse‐gravure, curtain, spray), laboratory‐scale calenders, ink‐surface interaction testers (ISIT), contact angle instrumentation (multidispenser system) and microscopy (multimode AFM).
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Characterization and Control of Pigment Coating Structures(C‐Coat) Main funding: Finnish Funding Agency for Technology and Innovation (Tekes) Participating FunMat units: LPCC, DPC Liisa Sinervo, Thomas Byholm, Marie Käld, Andreas Lemström, Niklas Nylund, Christoffer Stoor, Otto Järvinen, Jani Kniivilä, Joakim Järnström, Jouko Peltonen, Martti Toivakka Most physical and functional properties pigment coated papers are controlled by the microscopic structure of the coating layer. The objective of the project is to increase our understanding of the interrelations between coating raw materials, the microscopic porous structures resulting from these, and the end‐use properties of coated paper. The main areas of research include physical and surface chemical characterization of two and three dimensional coating layer structures, optical properties of coatings and liquid penetration in porous structures. The results of the project range from coating surface characterization on different length scales to computer‐based experimentation and prediction of optical and liquid absorption properties of coatings. Collaboration: Helsinki University/Observatory, University of Jyväskylä/Department of Physics, ABB Oy, Ciba Specialty Chemicals Oy, M‐real Oyj, Metso Paper Oy, Omya Oy, Specialty Minerals Nordic Oy, Stora Enso Oyj and UPM‐Kymmene Oyj. Publications: S. Wang, J. Järnström, P. Ihalainen and J. Peltonen: The effect of base paper and coating method on the surface roughness of pigment coatings. Journal of Dispersion Science and Technology 30 (2009), 961‐968. T. Byholm, J. Westerholm, M. Toivakka, Effective packing of 3‐dimensional voxel‐based arbitrarily shaped particles, submitted to Powder Technology, 2008 J. Järnström, P. Ihalainen, K. Backfolk, J. Peltonen, Roughness of pigment coatings and its influence on gloss, Applied Surface Science 254, 5741‐5749, 2008. M. Toivakka, J. Preston, P. Heard, Visualisation, Modeling and Image Analysis of Coated Paper Microstructure: Particle Shape − Microstructure Interrelations, in Proceedings of 2nd International Papermaking and Environment Conference, Tianjin, 2008. O. Järvinen, Modellering av bindemedel i bestrykningsskikt: algoritmer och kodoptimering, MSc‐thesis, Åbo Akademi, 2008 (in Swedish). A. Lemström, Inverkan av pigmentets partikelform på egenskaperna hos bestruket papper, MSc‐thesis, Åbo Akademi, 2008 (in Swedish).
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Improved Printability through Atmospheric Pressure Plasma Surface Treatment (Plastek) Main funding: Finnish Funding Agency for Technology and Innovation (Tekes) Participating FunMat unit: LPCC Maiju Pykönen, Martti Toivakka The project evaluates suitability and the (industrial) applications of the atmospheric pressure plasma treatment for in‐line roll‐to‐roll processing, and aims at increasing our understanding of the effects of plasma treatment of natural fiber‐based substrates. Of specific interest is the improvement of the offset and inkjet printability of uncoated and coated papers and paper boards by atmospheric pressure plasma surface treatment. In addition to plasma activation, the possibility to influence the printability through use of plasma deposition that can create atomic monolayer surfaces with desired surface chemical and energy properties is explored. Collaboration: Tampere University of Technology, VTT, Stora Enso Oyj, UPM‐Kymmene Oyj. Vetaphone, Millidyne and Omya Oy Publications: M. Pykönen, H. Sundqvist, M. Tuominen, J. Lahti, J. Preston, P. Fardim, M. Toivakka, Influence of atmospheric plasma activation on sheet‐fed offset print quality, Nordic Pulp and Paper Research Journal, Vol 23, no.2, 2008.
M. Pykönen, H. Sundqvist, O.‐V. Kaukoniemi, M. Tuominen, J. Lahti, P. Fardim, M. Toivakka, Ageing effect in atmospheric plasma activation of paper substrates, Surface and Coatings Technology, 202, 3777‐3786, 2008
M. Pykönen, H. Sundqvist, J. Järnström., O.‐V.. Kaukoniemi, M. Tuominen,J. Lahti, J. Peltonen, P. Fardim and M. Toivakka, Effects of Atmospheric Plasma Activation on Surface Properties of Pigment‐Coated and Surface‐Sized Papers. Applied Surface Science 255 (2008), 3217–3229.
Pykönen M., Silvaani H., Preston J., Fardim P. and Toivakka M., Influence of Plasma Activation on Ink Component Absorption in Sheet‐Fed Offset Printing. Submitted to TAGA Journal, 2008.
Pykönen M., Johansson K., Dubreuil M., Vangeneugden D., Ström G., Fardim P. and Toivakka M., Evaluation of Plasma‐Deposited Hydrophobic Coatings on Pigment‐Coated Paper for Reduced Dampening Water Absorption. Submitted to Journal of Adhesion Science and Technology, 2008.
Pykönen M., Silvaani H., Preston J., Fardim P. and Toivakka M., Influence of Plasma Activation on Absorption of Ink Components and Dampening Water in Sheet‐Fed Offset Printing. 35th International Research Conference, Advances in Printing and Media Technology, September 7‐10 2008, Valencia, Spain.
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Towards Novel and Cost‐Efficient Coating Binder Systems ‐ Optimal Binder Usage in Coated Paper (OptiBind) Main funding: Finnish Funding Agency for Technology and Innovation (Tekes)
Participating FunMat units: LPCC, LPT Parvez Alam, Farid Touaiti, Carl‐Eric Wilen, Martti Toivakka The project aims at increasing the understanding of binder functionality in pigment coatings. In order to ensure adequate surface strength of pigment coated paper for finishing and end‐use purposes, a sufficient amount of binder has to be used. When reducing binder levels in pigment coatings below a certain threshold to reduce costs, various problems appear that are related to mechanical failure in the coating layer. Solutions to the problem are searched through experiments that elucidate, at the molecular level, the interactions between binders, dispersants and coating pigments, and development and testing of modified pigment or latex dispersants/additives that improve the interfacial strength between coating pigments, binders and fibers. Collaboration: University of Jyväskylä, BASF Oy, Dow Suomi Oy, Imerys Minerals Oy, Oy Keskuslaboratorio ‐ Centrallaboratorium Ab, M‐real Oyj, Stora Enso Oyj and UPM‐Kymmene Oyj Publications: P. Alam, S. Mathur, T. Byholm, O. Järvinen, J. Kniivilä, M. Toivakka, A theoretical approach to understanding microstructure‐tensile modulus relations in paper coatings, In proceedings of the TAPPI 10th Advanced Coating Fundamentals Symposium, TAPPI Press, Atlanta, 2008.
Alam, P., Mathur, S., Byholm, T., Järvinen, O., Kniivilä, J. and Toivakka, M. (2008); Micro‐mechanics of high porosity particle‐polymer composites; Proceedings of the 2nd International Conference on Heterogeneous Material Mechanics, Huangshan, China, 2008.
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Optimisation of Blade Geometry for Coating of Fine Paper Using Wear‐Resistant Blades Main funding: Industry Participating FunMat unit: LPCC Parvez Alam, Christoffer Stoor, Prem Kumar Seelam, Martti Toivakka The project aims at understanding the blade mechanics in the blade coating of paper, and proposing new, improved blade geometries for coating of board and fine paper. A computer‐based complex inter‐coupled multi‐physics model was developed to account for backing roll, base paper, pigment filter cake and, if desired, polymeric blade surface compression. Based on numerical simulations of pigment coating suspensions modelled with one‐phase fluid of non‐Newtonian rheology, a better understanding of the blade mechanics have been obtained. Collaboration: Publication: P. Alam, M. Toivakka, Micro‐buckling of paper during blade metering, Computers and Chemical Engineering, vol 32, p. 600‐607, 2008.
Microscopic Modeling of Coating Layer Consolidation Main funding: Oy Keskuslaboratorio ‐ Centrallaboratorium Ab, PaPSaT Participating FunMat unit: LPCC Anders Sand, Martti Toivakka The project aims at (a) clarifying what kind of microscopic structures exist in pigment coating colors during consolidation, and (b) predicting how the wet state coating structure is reflected in the final dried coating layer structure and related coated paper end‐use properties. The project utilizes numerical tools developed at the laboratory to model concentrated colloidal suspensions and to follow the microscopic motion of individual particles in the consolidating coating layer. The results have clarified relevance of the various theories proposed in literature to control consolidation of pigment coating layers. Collaboration: VTT, KCL
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Publications: A.Sand, M. Toivakka, T. Hjelt, Small particle mobility in consolidating coating layers, Nordic Pulp and Paper Research Journal, volume 23(1), 52.56, 2008.
A.Sand, M. Toivakka, T. Hjelt, Influence of drying strategy on coating layer structure formation, Nordic Pulp and Paper Research Journal, volume 23(1), 46.51, 2008.
A.Sand, M. Toivakka, T. Hjelt, Investigation of filtercake stability using numerical simulation technique, TAPPI Journal, vol. 7(2), 4‐10, 2008. Sand, A., Toivakka, M. and Hjelt, T., Coating Layer Consolidation and the Influence of Drying Strategy ‐ A Numerical Study, Proceedings of Progress in Paper Physics Seminar, June 2‐5, Espoo, Finland, 65‐67, 2008. Sand, A., Toivakka, M. and Hjelt, T., Small Particle Migration Mechanisms in Consolidating Pigment Coating Layers, Proceedings of TAPPI Advanced Coating Fundamentals Symposium, June 11‐13, Montreal, Canada, 289‐298, 2008.
Tailored nanostabilizers for biocomponent interfaces (Taina) Main funding: Finnish Funding Agency for Technology and Innovation (Tekes) Participating FunMat units: LPCC, DPC Helka Juvonen, Manuela Tigerstedt, Jouko Peltonen The objective of the project Taina (VTT, TKK, ÅAU) has been to develop technologies for modification and assembly of biopolymers, i.e. proteins or selected carbohydrates suitable as nanostabilizers of sensitive biocomponents. Special emphasis is concentrated on chemo‐enzymatic functionalization of biopolymeric building blocks in order to create enhanced self‐assembly, integrity and performance of nanoparticles. These functional nanoscale particles will be exploited in food systems and for tailored barrier/sensing systems in food packages. A wide range of proteins (e.g. β‐lactoglobulin, whey protein, casein, coactosin) and peptides have been studied by their coating and film formation properties, and the possibility to modify their functionality by enzymes (e.g. laccase, tyrosinase). Besides morphology, AFM and e.g. ToF‐SIMS studies have yielded information about the reaction mechanisms between enzymes and proteins. Collaboration: VTT, TKK, YKI (Tukholma), Lumene Group, Billerud, Uniq Bioresearch
Publications:
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Good quality for wood and fibre‐based materials ‐ Nano‐mediated mega value for wood and fibre based products (NaMeWood) Main funding: Finnish Funding Agency for Technology and Innovation (Tekes) Participating FunMat units: LPCC, DPC Shaoxia Wang, Jouko Peltonen The properties of wood and laminated wood composite material produced can be modified by different nanostructures, such as nanoparticle additives and nanocoatings. The properties to be improved are controlled water vapor permeability and release of wood based VOCs, moisture resistance, resistance against UV radiation and weather, soil resistance as well as mechanical durability of wood surfaces (scratch resistance and surface hardness). Nanotechnology and nanostructures enable adaptable coating solutions for board and fine paper products; better converting properties for board and repellent, anti‐fouling characteristics for paper products (for instance wall papers, security papers). Paper printability properties can also be modified by introducing of nanostructures to paper surface compositions.
The overall objective of the research is to enhance competitiveness of wood, wood composite, pulp and paper materials in global markets. Collaboration: VTT, Teknos Oy, Millidyne Oy, Koskisen Oy, Stora Enso Oyj, and Stora Enso Laminating Paper Oy Publications: S. Wang, J. Järnström, P. Ihalainen, J. Peltonen, The effect of base paper and coating method on the surface roughness of pigment coatings, Journal of Dispersion Science and Technology 30, 2009, in press. S. Wang, R. Mahlberg, S. Jämsä, J. Mannila, J. Nikkola, and J. Peltonen, Surface characteristics of pine and heat‐treated spruce modified with alkoxysilanes by sol‐gel process. In Proceedings of the 6th international woodcoatings congress (2008).
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Surface proximity assay (Supra II) Main funding: Finnish Funding Agency for Technology and Innovation (Tekes) Participating FunMat units: DPC, LPCC Sari Pihlasalo, Jouko Peltonen The aim of the research projects has been to construct a homogeneous assay principle on a dyed planar surface for high‐throughput β2‐adrenergic receptor screening purposes. The methodology relies on a planar surface containing dye layers of nanometer thickness and energy transfer between the surface and a soluble molecule in solution recognizing a specific compound of interest. The interactions have been studied on molecular level by using probe microscopy techniques with the goal of distinguishing specific interactions for non‐specific ones. The bioaffinity reaction occurs directly on a lipid layer coated over the planar dye‐surface within a specified hydrophilic/hydrophobic area. Lipid monolayers and bilayers (< 6 nm) have been formed on the developed planar surface using Langmuir Blodgett and Schaefer techniques. β2‐adrenergic receptors have been successfully immobilized on the planar surface through fusion of receptor vesicles or direct coupling during the lipid film formation. Functional assay has been studied and conducted using energy transfer principle. Collaboration: University of Turku, University of Oulu, KSV Instruments, Innotrac Diagnostics, Perlos, Releco‐Coating Publications: M. Siltanen, E. Vuorimaa, H. Lemmetyinen, P. Ihalainen, J. Peltonen, M. Kauranen, Nonlinear Optical and Structural Properties of Langmuir‐Blodgett Films of Thiohelicenebisquinones, J. Phys. Chem. B 112, 1940‐1945, 2008.
H. Härmä, L. Dähne, S. Pihlasalo, J. Suojanen, J. Peltonen, P. Hänninen, Sensitive quantitative protein concentration method using luminescent resonance energy transfer on a layer‐by‐layer europium(III) chelate particle sensor, Analytical Chemistry 80, 9781‐9786, 2008.
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Strength, role and removal of nanoparticle‐based nonspecific binding in bioaffinity assay and bioimaging systems using electrostatic transferor (Eltrans) Main funding: Academy of Finland Participating FunMat unit: DPC Anni Määttänen, Jouko Peltonen Increasing number of highly luminescent nanoparticle labels in bioaffinity assays and bioimaging has become problematic in respect to nonspecific binding of the labels coupled with biomolecules. The larger size of nanoparticles and the high number of biomolecules on the particulate labels and, therefore, increased number of interactions compared to soluble biomolecules are the primary reasons for higher nonspecificity. The aim of the proposed project is to study and understand fundamental phenomena behind nonspecific binding of nanoparticle labels in bioaffinity assay and bioimaging systems and fabricate an electrostatic transferor to calculate and reduce background signal in biological measurement systems. Atomic force microscopy is used independently to calculate binding forces and the results of the methods are cross‐correlated. Polystyrenenanoparticle labels and quantum dots of different surface properties and sizes in combination with different antibodies on nanoparticles and solid‐phases are prepared and their effects on nonspecific interactions are investigated in detail. Antibodies and their recombinant fragments are used to elucidate the origin and role of nonospecificity. Thyroid‐stimulating hormone and prostate‐specific antigen are model analytes in the study. Collaboration: University of Turku, TKK Publications: J. Chen, A. Fallarero, A. Määttänen, M. Sandberg, J. Peltonen, P. Vuorela, M.‐L.. Riekkola, Living cells of staphylococcus aureus immobilized onto the capillary surface in electrochromatography: a tool for screening of biofilms, Analytical Chemistry, 80, 5103‐5109, 2008.
M. Sandberg, A. Määttänen, J. Peltonen, P. Vuorela, A. Fallarero, Automating a 96‐well microtitre plate model for Staphylococcus aureus biofilms: an approach to screening of natural antimicrobial compounds, International Journal of Antimicrobial Agents, 32, 233‐240, 2008.
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Bioactive paper and fibre products (BioAct)
Main funding: Finnish Funding Agency for Technology and Innovation (Tekes) Participating FunMat units: LPCC, LPT Piia Gustafsson, Serap Sahin, Pernilla Sund, Carl‐Erik Wilen, Martti Toivakka, Jouko Peltonen Bioactive features may provide new markets and added value products, for example, to pulp and paper, packaging, diagnostic and construction industry. General objective of this proposed project is to develop basic concepts, materials and mass manufacturing methods for producing bioactive paper or fibre based products on large areas. Methods to commercialize potential applications are clarified. Objective is to demonstrate bioactive systems, which detect and/or remove selected molecules (e.g. allergen, toxin), and can be manufactured with mass manufacturing methods on large area. Potential applications include e.g. active and intelligent food casing, anticounterfeiting, printable indicators on magazine or newspaper, construction materials and filters. The contribution by the Laboratory of Polymer Technology to the BioAct project consists of two parts: a) synthesis of a macrocycle library, and b) development of a printable monomer mixture, that gives a hydrogel after UV‐initiatied polymerization. The macrocycle library, which is synthesized on polystyrene beads, is intended for macrocycle‐functionalization of (bio)polymers, to be used primarily for sensors, but also for other applications. The task of the macrocycles is to achieve strong and specific interaction with the analytes. Although combinatorial libraries have been used extensively for drug discovery, few have been developed for other industrial purposes. For industrial applications, the priority is cheap monomers and synthesis, and good chemical stability. Macrocycles are preferred to open chains because the conformational preorganisation in macrocycles gives stronger and more specific association to the target. Macrocycles also have the ability to strike a compromise between structural preorganisation and flexibility to achieve optimal binding. The macrocycle library is synthesized using solid‐phase synthesis (SPS) on polystyrene beads, as a one bead ‐ one compound library using the mix‐and‐split method. The macrocycle is attached to the polystyrene bead using a linker, which will be cleavable for the library, but permanent for the final application. The linker attachment point on the macrocycle ('head monomer') also functions as the site for ring‐closure. The rest of the macrocycle consists of an amide oligomer. The chemistry used for ring‐closure is 1,3‐dipolar cycloaddition between a propargyl group and an azide group, the latter attached to the end monomer. For the first attempt at making a macrocycle, a phenacyl linker, and a rather complex head monomer syntheized in solution was used. The completed 14 atom macrocycle was cleaved off
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with hydrazine, chromatographically purified and characterized by nuclear magnetic resonance (NMR) and mass spectrometry (ESI‐MS). Because of different shortcomings, a new linker and a smaller and more easily synthesized head monomer was also made, and the testing of these is ongoing. Hydrogels have been studied as well. A printable hydrogel must remain liquid in the printing process, and then be cured into a non‐flowing hydrogel afterwards. To achieve this, UV‐polymerizable inks based on acrylic acid monomers have been tested. Collaboration: VTT, TKK, University of Lapland, Hansaprint Oy, UPM‐Kymmene Oyj, Tervakoski Oy, Ciba SC Oy, Eagle Filters Oy, Starcke Oy Securities, Oy Medix Biochemica Ab, Orion Diagnostica Oy Publications:
Printability on paper and board Main funding: Industry Participating FunMat units: DPC, LPCC Petri Ihalainen, Jouko Peltonen The aim of the project is to carry out versatile surface characterization for paper and board samples. Of special interest have been topographical and thermal properties of polymer films. Publications: K. Backfolk, J. Peltonen, N. Triantafillopoulos, S. Lagerge and J. B. Rosenholm, The Influence of Lubricating Agents on the Formation of a Film of a Styrene/Butadiene Latex, Tribology Letters 29, 57‐66, 2008.
K. Backfolk, P. Sirviö, P. Ihalainen, J. Peltonen, Thermal and Topographical Characterization of Polyester‐ and Styrene/Acrylate‐Based Composite Powders by Scanning Probe Microscopy. Thermochimica Acta 470, 27‐35, 2008.
P. Ihalainen, K. Backfolk, P. Sirviö, J. Peltonen, Thermal Analysis and Topographical Characterization of Films of Styrene‐Butadiene Films. Journal of Applied Polymer Science 109, 322‐332, 2008.
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Paper coatings for printed intelligence Main funding: Industry Participating FunMat unit: LPCC Kenneth Nylander, Mikael Ek, Jouko Peltonen Printed electronics is a rapidly developing area of industry. The objective of the project is to apply nano materials as paper coatings for printed electronic applications. Special emphasis is on the structure‐performance relationships and thorough characterization of the novel coatings. Collaboration: Ciba Finland Oy Publications:
Development of paper for inkjet printing Main funding: Industry Participating FunMat units: LPCC, DPC Carl‐Mikael Tåg, Jarl B. Rosenholm, Jouko Peltonen Papers available on the market for high speed inkjet printing can roughly be divided into treated grades and high quality specialty paper grades. The treated grades usually perform well in 1‐color printing, printing of barcodes etc., but not so well in 4‐color printing. The very expensive high quality specialty papers perform well in 4‐color printing, but not always so well in printing bar codes. Currently the high quality specialty paper grades are mainly produced on small paper machines, due to limited production possibilities. The aim of the Inkjet paper project is to develop paper grades which perform well in high speed inkjet printing, but with less complex structure and at a lower cost than current specialty inkjet papers. To do this, evaluation of what makes a paper good or bad for high speed inkjet printing will be carried out. Additionally the aim is to decrease the paper waviness which causes problems in the post handling process of the printed product.
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Printable array platform for cell studies (PrinCell)
Main funding: Finnish Funding Agency for Technology and Innovation (Tekes) Participating FunMat units: LPCC, Helka Juvonen, Tapio Mäkelä, Jouko Peltonen Recent advances in materials science and printing technology offer exciting opportunities to develop completely new types of functional surfaces and patterned device structures. In the field of biotechnology and tissue engineering, cell printing is considered as a very promising and potential technique for producing assays and arrays for applications where quick and inexpensive mass production of assays combined with high spatial resolution of deposited active components are needed. In this project we are combining the knowledge from different disciplines to develop technology base for printable advanced cell arrays. The key issue of the proposal is to combine versatile materials research and development with that of advanced printing and coating techniques that enable versatile and inexpensive printing of various biomaterials to complex assays. Essentially, different printing and coating techniques need to be studied because different kinds of materials are involved in preparation of a cell array. The printing technology can be combined and applied into the existing array technology to allow the use of current detection systems. Collaboration: University of Helsinki, Massachusetts Institute of Technology, UPM‐Kymmene, Orion Pharma, ChipMan, Wallac Perkin Elmer
Publications:
Liquid flame spray nanocoating for flexible roll‐to‐roll web materials (Nanorata) Main funding: Finnish Funding Agency for Technology and Innovation (Tekes) Participating FunMat unit: LPCC Milena Stepien, Jarkko J. Saarinen, Martti Toivakka
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The project is a collaborative effort to develop a novel nanocoating, liquid flame spray technique for flexible roll‐to‐roll web materials such as paper, paperboard or plastic. In this technique, the web‐like material rolls moderately fast through the liquid flame spray or an array of flames. Nanoparticles of size 5‐50 nm generated in the flame are deposited on the surface of the web material creating new properties for the surface. Based on earlier recent work, e.g., surface energy, barrier properties and adhesive properties can be increased. Performance of coatings with coverage in the order of one monolayer of nanoparticles is applicable and has been verified. The project consists of a) a 3 year period of more fundamental studies on selecting the best compounds applicable by this technique to improve the material and, b) a 2 year period to up‐scale the process for a wider web using an array of flames to achieve a smooth and even coating. Collaboration: Tampere University of Technology, Beneq Oy, Kemira Oyj, Stora Enso Oyj, and UPM‐Kymmene Oyj Publications:
Thermal Effects and Online Sensing (THEOS) Main funding: Finnish Funding Agency for Technology and Innovation (Tekes) Participating FunMat unit: LPCC Hanna Koivula, Martti Toivakka The project investigates the influence of temperature distribution on ink‐setting and printability in HSWO printing, determined by experiment, modelling and the (on‐line) measurement of ink‐setting behaviour adopting novel optical devices. Furthermore, an objective is to improve the understanding of heat transfer in pigment coatings in general. The thermal properties of coatings are relevant in several paper manufacturing, converting and printing processes, such as dry coating, calendering and electrophotography. Collaboration: Helsinki University of Technology, Joensuu University, BASF Oy, Omya Oy, M‐Real Oy, UPM‐Kymmene Oyj, MGM Devices Oy, and Finnish Graphic Industry Research Foundation Publications:
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1.2.5. To understand the electrical, optical and magnetic properties of disordered organic materials
In order to successfully make “intelligent packages”, there is a need to print at basically no cost power sources (i.e. batteries or photovoltaic cells), active components such as transistors and memory cells, as well as INPUT/OUTPUT units, all operating at low‐voltages. This requires a totally new approach to electronics: simple device design and innovative solutions. Traditional organic electronics usually suffers from stability issues and high drive‐voltages; especially for transistors. The use of ions usually offers robust performance at low voltages with less stringent needs for encapsulation, opening up a totally new field in device physics of organic electronics. In order to fully utilize the possibilities that functional materials provide, we need to clarify the electro‐optical and magnetic properties of the functional materials. This allows us to fully utilize the novelty of the materials in printed functionality. We are especially focusing our attention towards the following tasks:
– To understand electro‐optical properties such as charge transport and recombination,
magnetic and optical properties of disordered organic materials
– New experimental and numerical modeling tools
– to develop novel solution processable electronic devices for printable active electronics
devices, sensors and indicators
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The effects of metal impurities in an organic semiconductor on field‐effect transistor properties Main funding: Academy of Finland
Participating FunMat unit: DPh Niklas Björklund, Jan‐Olof Lill, Johan Rajander and Ronald Österbacka We have used Particle Induced X‐ray Emission (PIXE) analysis and Particle Induced Gamma‐ray Emission (PIGE) analysis to determine the elemental impurity concentrations in thieno[2,3‐b]thiophene samples that have undergone different washing and extraction procedures to remove impurities. Field‐effect transistors (FETs) were fabricated from the materials and their electrical characteristics show no significant differences between the devices made from different material samples. Reducing the metal residue levels below the one measured in the starting material (300 mg/kg Fe, 7 mg/kg Zn, 3000 mg/kg Pd and 12000 mg/kg Sn) does not improve the FET performance. This suggests that it is not necessary to completely remove metal residues in semiconducting polymers used in FETs.
1000 100001E-3
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Fig. Typical field effect mobilities for the different materials. The linear mobilities where measured at a constant drain voltage of Vd = ‐5 V and the saturated at Vd = ‐50 V. The error bars show the maximum deviation between the measured mobility values and average mobilities.
Collaboration: Accelerator Laboratory, National PET center, Åbo Akademi University, Laboratory of Analytical Chemistry, Åbo Akademi University, Merck Specialty Chemicals Ltd, Southampton, United Kingdom
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Publication: N. Björklund, J‐O Lill, J. Rajander, R. Österbacka, S. Tierney, M. Heeney, and M. Coelle, The effects of metal impurities in an organic semiconductor on field‐effect transistor properties, Organic Electronics, 10, 215‐221 (2009)
Simulations of hopping transport in disordered organic materials Main funding: Academy of Finland, Finnish Funding Agency for Technology and Innovation (Tekes) and Graduate School of Materials Research (GSMR) Participating FunMat unit: DPh F. Jansson and R. Österbacka For hopping transport in disordered materials, the mobility of charge carriers is strongly dependent on the temperature and the electric field. By numerical simulation we have studied the energy distribution and the mobility of charge carriers, as a function of electric field, temperature and carrier concentration. We have shown that both the energy distribution and the mobility can be described by a single parameter, the effective temperature, which is dependent on the magnitude of the electric field.
We have also studied the effects of strong electric fields on hopping conductivity. Monte Carlo computer simulations show that the analytical theory of Nguyen and Shklovskii , [Solid State Commun. 38, 99 (1981)] provides an accurate description of hopping transport in the limit of very high electric fields and low concentrations of charge carriers as compared to the concentration of localization sites and also at the relative concentration of carriers equal to 0.5. At intermediate concentrations of carriers between 0.1 and 0.5, computer simulations evidence essential deviations from the results of the existing analytical theories. The theory of Nguyen and Shklovskii also predicts a negative differential hopping conductivity at high electric fields. Our numerical calculations confirm this prediction qualitatively. However the field dependence of the drift velocity of charge carriers obtained numerically differs essentially from the one predicted so far. Analytical theory is further developed so that its agreement with numerical results is essentially improved.
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Fig. Drift velocity as a function of the electric field for different localization lengths. The curves show the theory in the limit of large electric fields. The system size L is 20R.
Collaboration: Department of Physics and Material Sciences Center, Phillips‐University Marburg, Germany, Institute of Semiconductor Physics and Novosibirsk State University, Novosibirsk, Russia, Department of Solid State Electronics, Vilnius University, Vilnius Lithuania
Publications: F. Jansson, S. D. Baranovskii, G. Sliauzys, R. Österbacka, P. Thomas, Effective temperature for hopping transport in a Gaussian DOS, Phys. Stat. Sol. (c) 5, 722 (2008) / DOI 10.1002 pssc. 200777567 F. Jansson, S. D. Baranovskii, F. Gebhard, and R. Österbacka, Effective temperature for hopping transport in a Gaussian DOS, Physical Review B 77, 195211 (2008).
A. V. Nenashev, F. Jansson, S. D. Baranovskii, R. Österbacka, A. V. Dvurechenskii, and F. Gebhard, Hopping conduction in strong electric fields: Negative differential conductivity, Physical Review B 78, 165207 (2008).
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Organic Spintronics Main funding: Academy of Finland
Participating FunMat unit: DPh S. Majumdar, H.M. Majumdar and R. Österbacka
Organic spintronics is a part of the research conducted in the Department of Physics, Åbo Akademi University in collaboration with the Magnetism and Superconductivity group of Wihuri Physical Laboratory, University of Turku. We study the basic spin physics of different inorganic and organic materials suitable for spintronic applications and also fabricate spintronic devices and characterize them. Research related to organic spintronics in this group is mainly two‐fold. On one hand, organic spin valve devices are fabricated using ferromagnetic (FM) La0.7Sr0.3MnO3 (LSMO) and Co as the spin injecting and detecting electrodes and different organic semiconductors (OS) as non magnetic spacers and their properties thoroughly characterized. The best spin valve device, so far, showed more than 80% magnetoresistance (MR) at 5K and detectable room temperature MR response in our devices. Studies are underway to improve this signal for potential applications. On the other hand, organic diode devices are fabricated and their magneto‐transport properties are studied for understanding the basic physics leading to large MR response of most OS based diodes at room temperature and low magnetic fields (OMAR effect). Magnetoelectrical measurements were performed on diodes and bulk heterojunction solar cell blends to clarify the role of formation of Coulombically bound electron‐hole (e‐h) pairs on the magnetoresistance (MR) response in organic thin‐film devices. Bulk heterojunction solar cells are suitable model systems because they effectively quench excitons but the probability of forming e‐h pairs in them can be tuned over orders of magnitude by the choice of material and solvent in the blend. We have systematically varied the e‐h recombination coefficients, which are directly proportional to the probability for the charge carriers to meet in space, and found that a reduced probability of electrons and holes meeting in space lead to the disappearance of the MR. Our results clearly show that MR is a direct consequence of the e‐h pair formation.
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Fig. %MR as a function of magnetic field (B) in different devices with varying L ratio in a RRP3HT diode (black), in a RRP3HT:PCBM BHSC (red) made from dicholorobenzene and chloroform (blue), and in a MDMO‐PPV:PCBM BHSC (green).
Collaboration: Wihuri Physical Laboratory, University of Turku, (Prof. R. Laiho), Department of Chemistry, University Hasselt, (Prof. Vanderzande), HUT, Nanomaterials group, (Prof. S. van Dijken). Publications: S. Majumdar, H.S. Majumdar, H. Aarnio, D. Vanderzande, R. Laiho, and R. Österbacka, “The role of electron‐hole pair formation on organic magnetoresistance”, Physical Review B 79, 201202R (2009). S. Majumdar, H. Majumdar, R. Laiho, and R. Österbacka, “Organic spin valves: effect of magnetic impurities on the spin transport properties of polymer spacers”, New Journal of Physics, 11, 013022 (2009). (11pp) S. Majumdar , H. S. Majumdar, H. Aarnio, R. Laiho and R. Österbacka, ”Magnetoresistance Study in Poly (3‐hexyl thiophene) Based Diodes and Bulk Heterojunction Solar Cells”, Phys. Stat. Solidi (a), in press (2009). S. Majumdar, H. S. Majumdar, D. Tobjörk, and R. Österbacka, “Towards printed magnetic sensors based on organic diodes”, Physica Status Solidi: A (2009)
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Study of Half‐metallic manganite La0.67Sr0.33MnO3 (LSMO) thin films made by pulsed laser deposition for spintronic applications. Main funding: Academy of Finland Participating FunMat unit: DPh S. Majumdar, R. Österbacka
La0.67Sr0.33MnO3 (LSMO), a well‐known half‐metallic manganite has been successfully used as a spin injecting electrode in many inorganic/organic spintronic devices. Although the Curie temperature (TC) of bulk LSMO lies well above room temperature, the surface spin polarization start decreasing at a much lower temperature due to the presence of a large number of paramagnetic clusters at 300K giving much less SP carriers at the LSMO ‐ barrier interface in spintronic devices. Now, the Double – Exchange (DE) mechanism in manganites, which controls the charge carrier movement, is significantly modified by structural defects and substrate induced strains and also on the growth mechanisms. This makes it necessary to grow the LSMO films on different substrates starting from highly lattice mismatched MgO (MGO) (~9%) to most closely matched SrTiO3 (STO) (0.87%) and NdGaO3 (NGO) (‐0.2%) to obtain the best spin injector for our devices. In MGO and STO the strain is compressive while that in NGO is compressive. So, the growth mechanisms in these three kinds of substrates are very different and thus we studied the effect of differently strained films, evolution of strain with film thickness and modification of their spin injection properties. Also using different pulsed laser deposition (PLD) parameters like temperature and laser repetition rate, the growth and oxygen content of the material is modified and from the study of their surface morphology, atomic structures, magnetic and transport properties, we optimized the parameters for achieving maximum SP injection at room temperature.
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Fig. Magnetization vs. temperature plot of LSMO films on different substrates showing different spin polarization at room temperature.
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Collaboration: Wihuri Physical Laboratory, University of Turku (H. Huhtinen and R. Laiho) Publications: S. Majumdar, H. Huhtinen, H. S. Majumdar, R. Laiho and R. Österbacka,” Effect of La0.67Sr0.33MnO3 (LSMO) electrodes on organic spin valves”, Journal of Applied Physics 104, 033910 (2008).
Electrical characterization of organic memories using polarizable nanoparticles
Main funding: Finnish Funding Agency for Technology and Innovation (Tekes) (Nanoscale Memory Unit) and Academy of Finland Participating FunMat unit: DPh J. K Baral, H. S. Majumdar, and R. Österbacka
We demonstrate a memory device in which the fullerene‐derivative [6,6]‐phenyl‐C61 butyric acid methyl ester (PCBM) as well as metallic nanoparticles mixed with inert polystyrene (PS) matrix is sandwiched between two aluminum (Al) electrodes. Above a threshold voltage of <3V, independent of thickness, a consistent negative differential resistance (NDR) is observed in the devices of thickness range from 200nm to 350nm made from solutions with 4 wt% to 10 wt% of PCBM in PS. We found that the threshold voltage (Vth) for switching from high impedance state to low impedance state, the voltage at maximum current density (Vmax) and the voltage at minimum current density (Vmin) in the NDR regime are constant within this thickness range. The current density ratio at Vmax and Vmin is more than or equal to 10, increasing with thickness. Furthermore, the current density is exponentially dependent on the average hopping distance longest tunneling jump between two PCBM molecules, suggesting a multiple tunneling mechanism between individual PCBM molecules. This is further supported with temperature independent NDR down to 240K.
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Fig. a) Absolute current density as a function of voltage for pure polystyrene (PS, d = 200 nm) and 2‐6 wt% PCBM/PS compositions (d = 250 − 260 nm). (b) Current density as a function of voltage for 10‐40 wt% PCBM/PS compositions (d = 250 nm), showing ohmic behavior. (c) Strength of the electric field in the vicinity of two dielectric spheres where an initially uniform electric field (E0) is applied. (d) Combination of a TEM micrograph and a schematic illustration showing the polarisation between the PCBM clusters, separated by the PS matrix. All devices were annealed at 120°C.
Collaboration: Department of Engineering Physics and Mathematics, and Center for New Materials, Helsinki University of Technology and VTT Printed Electronics Center
Publications: J. K. Baral, H. S. Majumdar, A. Laiho, H. Jiang, E.I. Kauppinen, R. H. A. Ras, J. Ruokolainen, O. Ikkala, and R. Österbacka, Organic memory using the fullerene‐derivative [6,6]‐phenyl‐C61 butyric acid methyl ester (PCBM): Morphology, thickness and concentration dependence studies, Nanotechnology 19, 035203 (2008).
A. Laiho, J.K. Baral, H.S. Majumdar, F. Jansson, A. Soininen, R. Österbacka, and O. Ikkala, Influence of morphology on the electrical behavior of a polymer/fullerene composite memory device, Applied Physics Letters 93, 203309 (2008), DOI:10.1063/1.3033221.
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X‐ray photoelectron spectroscopy study on polymer/fullerene nanocomposites
Main funding: Åbo Akademi and Academy of Finland Participating FunMat unit: DPh Daniel Tobjörk, Jayanta Baral, Himadri Majumdar, and Ronald Österbacka We studied the chemical composition of memory devices as a function of depth by using X‐ray Photoelectron Spectroscopy (XPS) and sputtering with argon ions. The depth profile in the figure below shows the slightly oxidized aluminum top electrode, the carbon rich active material consisting of a mixture of polystyrene (PS) and [6,6]‐phenyl‐C61 butyric acid methyl ester (PCBM), the bottom aluminum contact and finally the glass substrate (containing silicon and oxygen).
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Fig. The composition of an Al/PS:PCBM/Al memory device is shown as a function of sputtering time in this depth profile. The atomic concentrations were determined from the area of the carbon (C1s), oxygen (O1s), aluminum (Al2p) and silicon (Si2p) peaks in the XPS spectrum. The broader shape of the bottom electrode was explained by the inhomogeneous sputtering process.
From the results we could conclude that the thermal evaporation of the aluminum electrodes had not led to any observable inclusion of aluminum (<0,1‐1 at.%.) into the active material layer. Furthermore, the observation of alumina on the bottom contact gave some clues to the understanding of the device operation principle. We also compared the XPS results with Transmission Electron Microscopy (TEM) images of cross sections of the memory devices. Collaboration: Department of Engineering Physics and Mathematics, and Center for New Materials, Helsinki University of Technology
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Publication:
A. Laiho, J. K. Baral, H. S. Majumdar, D. Tobjörk, J. Ruokolainen, R. Österbacka, and O. Ikkala, Imaging and elemental analysis of polymer/fullerene nanocomposite memory devices, Mater. Res. Soc. Symp. Proc., 1071, 1071‐F04‐04 (2008)
Charge Transport and Recombination in hybrid organic‐TiO2 based devices Main funding: Academy of Finland Participating FunMat units: DPh, DPC S. Sandén, Q. Xu, J‐H. Smått, M. Lindén and R. Österbacka The purpose of this project is to clarify the charge transport in hybrid organic–inorganic solar cells. The main materials studied are TiO2, poly(3‐hexylthiophene) (P3HT) and the fullerene derivative PCBM. By using nanostructured TiO2 that has pores through which the underlying substrate can be reached, we have the possibility to utilize this in the manufacturing of a novel intrinsic tandem solar cell. To clarify the charge transport and recombination in these devices, we are using time of flight (ToF), charge extraction by linearly increasing voltage (CELIV) and double injection (DoI) techniques. The use of these different techniques makes it possible to obtain quantities such as mobility, lifetime etc. which enable us to characterize the charge transport and recombination in these devices. We have measured charge transport and recombination of TiO2:P3HT films, where the TiO2 films have been flat, porous or nanostructured. By measuring on these different surfaces it is possible to separate the effect of the interface between TiO2 and P3HT. It has been concluded that the interface gives rise to a large amount of surface traps which affects the charge transport in these devices. Collaboration: Department of Solid State Electronics, Vilnius University, Vilnius, Lithuania, Department of Chemistry, University of Joensuu (Prof. T. Pakkanen) and Biomaterials center Univ. of Turku (Dr. S. Areva) and Department of Solid State Electronics, Vilnius University, Vilnius Lithuania. Publication: G. Sliaužys, G. Juška, K. Genevicius, G. Juška, J. H. Smått, M. Lindén, R. Österbacka, TiO2‐PHT interface influence to charge carrier photo generation and recombination, SPIE Proceedings 7142, 71420K (2008).
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Charge transport and recombination in bulk‐heterojunction solar‐cells
Main funding: Academy of Finland
Participating FunMat unit: DPh Mathias Nyman, Harri Aarnio, Simon Sanden, Gytis Sliauzys and R. Österbacka
One of the main factors limiting the conversion efficiency in organic solar cells is the recombination of the charge carriers. In low mobility materials a bimolecular Langevintype recombination is usually observed. Langevin recombination is caused by the probability for electrons and holes to meet in coordinate space, and therefore depends on the transport properties of the charge carriers.
We have previously shown that in bulk heterojunction solar cells made from blends of regioregular poly(3‐hexylthiophene) with [6,6]‐phenyl‐C61‐butyric acid methyl ester (RRP3HT:PCBM) the bimolecular recombination is reduced by 1000 times with respect to the Langevin recombination [1]. Using different experimental methods such as double injection current transients (DoI), integral mode time‐of‐flight (TOF), and charge carrier extraction with linearly increasing voltage (CELIV)we found that the bimolecular recombination coefficient � depends on density of the charge carriers n. This dependence is observed only in samples, where lamellar structures are formed.
In this work, we have shown that recombination in regioregular poly(3‐hexylthiophene):[6,6]‐phenyl‐C61‐butyric acid methyl ester (RRP3HT:PCBM) bulk heterojunction solar cells is caused by two‐dimensional (2D) Langevin recombination in the lamellar structures of RRP3HT, which are formed in the annealing process. Due to the 2D Langevin process, the bimolecular recombination coefficient is reduced in comparison to the 3D case, and also depends on the density of charge carriers.
Collaboration: Department of Solid State Electronics, Vilnius University, Vilnius, Lithuania, Linz Institute for Organic Solar Cells, Johannes Kepler University, Linz, Austria and Konarka Austria, Linz, Austria
Publications: Review: A. Pivrikas, G. Juška, K. Arlauskas, M. Scharber, N.S. Sariciftci, and R. Österbacka, Charge Transport and Recombination Polymer/Fullerene Organic solar cells, Progress in Photovoltaics 15, 677‐696 (2007).
G. Juska, G. Sliauzys, K. Genevicius, Nerijus Nekrasas, K. Arlauskas, and R. Österbacka, Two‐Dimensional Langevin Recombination, Applied Physics Letters, in press (2009)
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Photoexcitation dynamics in disordered organic materials Main funding: Academy of Finland Participating FunMat units: DPh Harri Aarnio, Mathias Nyman, Ronald Österbacka Optical properties of an electroluminescent poly(phenylene vinylene‐cofluorenylene vinylene) (BPPPV‐PF)‐based‐conjugated polymer using absorption, photoluminescence (PL), time‐resolved photoluminescence (TRPL), continuous wave (CW) and transient‐photoinduced absorption (PA) spectroscopic techniques. Transient photoinduced absorption measurements have been performed on the alternating polyfluorene copolymer, poly[2,7‐(9,9‐dioctylfluorene)‐alt‐5,5‐(4’,7’‐di‐2‐thienyl‐2’,1’,3‐benzothiadiazole)] (APFO3) on femtosecond to nanosecond timescales. Further, delayed fluorescence has been measured up to microsecond timescales. Based on these results we have created a model of the photoexcitation dynamics in the polymer. The model includes decay of singlet excitons and intrachain polaron pairs, but also build‐up and decay of interchain polaron pairs. The results are modeled numerically and the parameters which govern the generation and recombination processes are extracted. Collaboration: Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), Singapore, Lund Laser Center (Prof. V. Sundström) Publication: Chellappan Vijila, M. Westerling, H. Aarnio, R. Österbacka, Huang Chuna, Chen Zhikuana, Zhang Xinhaia, Zhu Furonga, and Chua Soo Jin, Nature and dynamics of photoexcited states in an electroluminescent poly(phenylene vinylene‐co‐fluorenylene vinylene)‐based p‐conjugated polymer, J. Photochem. Photobiol. A: Chem. 199, 358‐362 (2008); doi:10.1016/ j.jphotochem.2008.06.016
A Combined Optical and Electrical Method for Measuring Charge Carrier Dynamics in Bulk‐heterojunction Solar Cells Main funding: Academy of Finland (Morphoso) Participating FunMat unit: DPh M. Nyman, H. Aarnio, and R. Österbacka
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A novel method for measuring charge carrier dynamics in bulk‐heterojunction solar cells has been developed. The method combines transient photo‐induced absorption (tPA) with charge extraction by a pulsed voltage (CEPV). The transient photo‐induced absorption technique is used to optically study the decay rates of excitations on ns – µs timescales. Some of the charges are extracted by a voltage pulse and the subsequent alteration of the excitation decay rates is studied. The amount of extracted charges is measured and compared to the decrease in the photo‐induced absorption. The method has been tested on bulk heterojunction solar cells based on the conjugated polymer poly(3‐hexylthiophene‐2,5‐diyl) (P3HT) and the fullerene derivative [6,6]‐phenyl‐C61‐butyric acid methyl ester (PCBM).
Collaboration: Department of Solid State Electronics, Vilnius University, Lithuania, Bioorganic electronics, Linköping University, and Fraunhofer ISE. Publications:
Ion‐conducting membrane based organic transistors Main funding: Åbo Akademi Foundation and Åbo Akademi University Participating FunMat units: DPh, LPT Nikolai J. Kaihovirta, Carl‐Johan Wikman, Tapio Mäkelä, Carl‐Eric Wilén, and Ronald Österbacka
We have developed a novel concept of organic transistors that uses ion‐conducting membranes as gate insulators. The fabrication steps of the membrane‐FET (MemFET) can be shown to be fully implemented into a large‐area fabrication line. The thickness of the used membranes varies between 50 and 150 mm. Therefore, they may be used as mechanical support, removing (at least) one process step. The idea of using an insulator both as gate dielectric and support has been presented before.] In our case, however, the very thick membrane provides mechanical robustness, allowing at the same time low‐voltage operation with a high current output. We show that both a commercially available membrane and membranes optimized for different ionic species can be used for MemFETs. The membrane can be patterned to be locally ion conducting forMemFETs as well as for other purposes where a solid electrolyte is required. This concept also allows for multifunctional integration of organic devices on the selfsupported membrane, as illustrated in the last section where an electrochromic (EC) display pixel is connected to a MemFET that is integrated on the same membrane. Hence, the versatile properties of the membrane are successfully utilized.
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Fig. a) Schematic cross‐section of the MemFET. The membrane acts both as gate insulator and mechanical support. b) Output and c) transfer curves of a Nafion115 MemFET measured in inert atmosphere. d) Chronoamperometric response of a Nafion115 MemFET when switching between off and on states. The drain‐voltage is kept constant. Collaboration: Publications: N. J. Kaihovirta, C.‐J. Wikman, T. Mäkelä, C.‐E. Wilén, and R. Österbacka, “Self‐Supported Ion Conductive Membrane Based Transistors” Advanced Materials (2009). DOI: 10.1002/adma.200801817
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1.2.6. Printable active electronic sensors, indicators and devices When functional inks are used in applications, different printing and coating techniques are needed. To realize low‐cost roll‐to‐roll production of intelligent paper‐ and plastic based products, there is a need for high‐speed production techniques. The target for the Functional Printing Laboratory (FPL) is to demonstrate suitable roll‐to‐roll printing techniques for functional materials within FUNMAT as well as to develop novel methods for functional inks including e.g. insulating, semiconducting, conducting or magnetically responsive materials. The FPL hosts laboratory scale, versatile functional printing equipment for our partners. We have currently used reverse gravure coating (RG) and inkjet printing techniques to demonstrate printed organic electronic devices on both plastic and fibre‐based substrates. Due to the different nature of the functional inks one printing method cannot cover all the needs. Different solvents, viscosities, surface tensions or particle sizes play a large role for the print quality. Also the device configurations, alignment accuracy and minimum feature sizes are parameters which play a crucial role when choosing the most suitable printing process. We are also developing a novel continuous roll‐to‐roll manufacturing technique for testing and prototyping purposes. In our modular roll‐to‐roll table‐top printer (FUNPRINTER) at least five different printing units (gravure, flexo, coating, ink‐jet, and lamination) can be used sequentially. We can analyze the printing parameters in‐situ since speed of the web can be controlled from 0.1 meters/minute up to 20 meters/minute. This small scale roll‐to‐roll device enables us to demonstrate fully printed applications already when only a few milliliters of functional inks are available and when the material of choice is not commercially available.
Surface energy patterning for inkjet printing in device fabrication Main funding: Finnish Funding Agency for Technology and Innovation (Tekes) Participating FunMat units: DPh, DPC Jian Lin, Per Dahlsten, Mika Linden, and Ronald Österbacka For application of device fabrication by inkjet printing, an accurate and high resolution patterning method is required. However, the printing resolution depends on the minimum size of inkjet nozzle, which is limited by the surface tension of the inks. And the quality of the inkjet printing also needs improvement because of wrong and satellite droplets. An expanded control of ink deposit in inkjet printing with substrate modifications can be used to improve the resolution of the devices. Our strategy is depositing a hydrophobic pattern on a hydrophilic substrate firstly, and thereafter prints the functional ink on top of the pattern with hydrophilic
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lines of suitable width. Higher resolution and better ink‐substrate combination can be obtained by this method. This visible and easy processing pattern can be used widely for more precise, thin and sharp lines, and smaller devices.
Fig. Schematic outline of the procedure for PI surface energy pattern by microcontact printing and inkjet printing on patterned PI.
Fig. Comparison of ink printed on a piece of patterned PI between areas with ODTS layer (right) and without ODTS layer (left side). The ink was printed as a matrix with 20 �m dot spacing.
Collaboration: Department of Electronics, Tampere University of Technology, Tampere, Finland, Vicinics consortium at Tampere University of Technology, plus industry Publications: Jian Lin, Jussi Pekkanen, Matti Mäntysalo, T. Mäkelä, and Ronald Österbacka “Utilization of selective patterning for inkjet printing in the electronics manufacturing”, IMAPS 2009 ATW on Printed Devices and Applications Jian Lin, Per Dahlsten, Jussi Pekkanen, Mika Linden, Matti Mäntysalo, and Ronald Österbacka “Surface energy patterning for inkjet printing in device fabrication”, Proceedings of SPIE Volume 7417 (2009), in press
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Printable Electronics based Sensor Platform Funding: Finnish Funding Agency for Technology and Innovation (Tekes) Participating FunMat unit: DPh Niklas Björklund, Fredrik Pettersson, Himadri Majumdar and Ronald Österbacka The main objective of this project is to develop printable electronics towards a technology platform suitable for development of embedded large area sensor applications. This goal can be split following objectives.
- combination of different printing process with various other (e.g. laser, electrical
sintering, etching) processing technologies in high volume processes
- producing printed platforms suitable for antenna, organic transistor, sensor and silicon
IC integration
- development of novel low voltage switching transistors for printed sensor multiplexing
using combinational processes
The main responsibility for the group at DPh is to develop solutions for R2R‐compatible low‐voltage organic field‐effect transistors (OFETs). Reducing the capacitive coupling is the key to low‐voltage operation (below 5 V); the efforts have therefore been concentrated to the dielectric layer. Several organic dielectrics and inorganic oxides have been studied, Al2O3 have so far proven to be the most promising approach.
Fig. Schematic layout of the low‐voltage Al2O3 OFET.
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Fig. A schematic image of the roll‐to‐roll reverse gravure coating process.
Fig. Typical transfer and output (inset) characteristics for the low‐voltage Al2O3 OFET.
Collaboration: Department of Electronics Oulu University, Department of Electronics, Tampere University of Technology, plus industrial partners. Publications:
Roll‐to‐roll fabrication of plastic solar cells
Main funding: Åbo Akademi Participating FunMat unit: DPh Daniel Tobjörk, Harri Aarnio, Tapio Mäkelä and Ronald Österbacka Plastic solar cells can be fabricated from solution processable materials on flexible substrates. This is a great advantage compared to silicon based solar cells, since this offers the possibility of using similar low‐cost large‐area roll‐to‐roll fabrication methods as are used in the printing industry. In this work we have studied the reverse gravure coating technique (see Fig. 2) as a way of producing thin homogeneous films for plastic solar cells.
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Fig. A schematic image of the architecture of the reverse gravure coated organic bulk
heterojunction solar cell.
Fig. J‐V curves of a reverse gravure coated and a spin coated plastic solar cell under simulated AM1.5 illumination (100 mW/cm2).
A schematic image of an organic bulk heterojunction type solar cell is shown in Fig. 3. The bottom poly(3,4‐ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT:PSS) layer is a hole conducting polymer, while the active layer is based on the conjugated polymer regioregular poly(3‐hexylthiophene‐2,5‐diyl) (P3HT) and the fullerene derivative [6,6]‐phenyl‐C61‐butyric acid methyl ester (PCBM).
The hole conducting PEDOT:PSS layer and the 100 nm thick active organic P3HT:PCBM layer were subsequently reverse gravure coated on an indium tin‐oxide (ITO) covered polyester (PET) film in ambient air. Working solar cells were achieved after annealing and thermal evaporation of the top contact (LiF and Al). The current‐voltage (J‐V) characteristics of the reverse gravure coated solar cell was measured under simulated AM1.5 illumination and compared with a reference solar cell that was fabricated by laboratory scale spin coating methods on a glass substrate in a nitrogen glove box (see Fig. 4). The power conversion efficiency (PCE) of the reverse gravure coated organic solar cells was determined to around 0.8% and was very close to the reference device. Collaboration: Publications: D. Tobjörk, H. Aarnio, T. Mäkelä, and R. Österbacka, Roll‐to‐Roll Fabrication of Bulk Heterojunction Plastic Solar Cells using the Reverse Gravure Coating Technique, Mater. Res. Soc. Symp. Proc. 1091E, 45 (2008). D. Tobjörk, H. Aarnio, T. Mäkelä och R. Österbacka, Masstillverkningsmetod för plastsolceller, Reflexer 10, 109 (2008).
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Fig. An image of flexible HIFETs.
All‐printed low‐voltage transistors on plastic substrates
Main funding: Åbo Akademi Foundation and Åbo Akademi Participating FunMat units: DPh Daniel Tobjörk, Nikolai Kaihovirta, Tapio Mäkelä and Ronald Österbacka
Conducting, semiconducting and insulating materials in solutions and dispersions provide the possibility of fabricating organic devices on flexible substrates with similar techniques as are used in the printing industry. We have manufactured organic transistors on low‐cost flexible substrates completely with fabrication techniques that allow a high throughput of devices at a low cost. All‐printed hygroscopic insulator field effect transistors (HIFETs) were demonstrated by ink‐jet printing all electrodes (from conducting polymer and silver nanoparticle inks) and applying the polymer semiconductor and insulator layers from solutions with the roll‐to‐roll reverse gravure coating technique in ambient air.
On problem with most organic transistors is the usually very high driving voltage (10‐100V), which is not suitable for portable electronics. However, the printed HIFETs operate at low‐voltage in ambient (humid) air, thanks to the ionic drift in the polymer insulator, poly(4‐vinylphenol) (PVP). We have also investiged the effect of the substrate roughness on the HIFETs and compared this with traditional organic FETs (OFETs). In Fig. 2. a comparison of devices fabricated on two different polyester substrates is shown. The root‐mean‐square (RMS) roughness of the PET‐505 substrate was measured to 4‐6 nm (by AFM on 20 μm ×20 μm areas) while the same value on the rougher low‐cost Mylar® A substrate was 25–50 nm. In opposite to the traditional OFETs the HIFETs were found to be rather insensitive to the roughness of the plastic substrates. Also the yield of working devices was found to be much higher with the HIFETs. This insensitivity to the surface roughness is due to the thick insulator layer (1‐2 µm) in combination with the ion modulation which also makes the transistor insensitive to variations in the insulator thickness.
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Fig. AFM images of (a) PET 505 and (b) Mylar® A substrates. Typical transfer curves for (c) HIFETs and (d) OFETs on PET 505 and Mylar®. The square root of the drain currents are shown for the same (e) HIFETs and (f) OFETs.
Collaboration: Publications: D. Tobjörk, N.J. Kaihovirta, T. Mäkelä, F.S. Pettersson, and R. Österbacka, All printed low‐voltage transistors, Organic Electronics 9, 931‐935 (2008) N. Kaihovirta, D. Tobjörk, T. Mäkelä, and R. Österbacka, Absence of substrate roughness effects on an all‐printed organic transistor operating at one volt, Applied Physics Letters 93, 053302 (2008). N. Kaihovirta, D. Tobjörk, T. Mäkelä, and R. Österbacka, Low‐Voltage Organic Transistors Fabricated using Reverse Gravure Coating on Prepatterned Substrates”, Advanced Engineering Materials, 10, 640 (2008).
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Printed low‐voltage organic transistors on paper
Main funding: Åbo Akademi and Åbo Akademi Foundation Participating FunMat units: DPh, LPCC Daniel Tobjörk, Nikolai Kaihovirta, Roger Bollström, Anni Määttänen, Tapio Mäkelä, Petri Ihalainen, Jouko Peltonen, Martti Toivakka and Ronald Österbacka Inspired by the robustness and printability of the hygroscopic insulator organic transistors (HIFETs) on the rough plastic substrate we were able to manufacture these transistors even on paper substrates. The recyclable paper based substrates were specially developed for this purpose. The ink‐jet printed silver nanoparticle elelctrodes were made conductive within 10 seconds by exposing them to an infrared lamp. Ink‐jet printing was also investigated as a way of applying the semiconductor and insulator layers. The output curve of a “paper transistor“that has been stored in ambient air for 4.5 months is shown in Fig. 1. Collaboration: Publications: R. Bollström, A. Määttänen, D. Tobjörk, P. Ihalainen, N. Kaihovirta, R. Österbacka, J. Peltonen and M. Toivakka, A multilayer coated fiber‐based substrate suitable for printed functionality, Organic Electronics (2009), doi:10.1016/j.orgel.2009.04.014
Ink‐jet printed organic diodes as magnetic sensors
Main funding: Åbo Akademi Foundation and Ministry of Education (FunPrint and FunPrim). Participating FunMat units: DPh Daniel Tobjörk, Himadri S. Majumdar, Sayani Majumdar, and Ronald Österbacka Diodes are important basic components in electronic circuits as rectifiers. By using suitable materials and architecture diodes are also used in the special areas of solar cells and light emitting diodes. Another interesting application of using organic diodes as magnetic sensors was opened up by the discovery of the organic magnetoresistance (MR) effect. We have studied ink‐jet printing as a way of manufacturing organic diodes and using them as magnetic sensors. The printed diodes were fabricated on flexible plastic substrates with pre‐
Fig. Output curve of a HIFET measured 4.5 months after the fabrication.
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patterned aluminum contacts. Both the polymer semiconductor and the top silver electrode were applied by ink‐jet printing. The silver nanoparticle ink was annealed on a hot plate at 120⁰C for 20 min before measuring the diodes. The printed devices showed a positive MR response of 10 – 15%, which was almost as good as for spin coated and evaporated devices. The device yield and stability of the printed devices was, however, not yet as good as for the laboratory scale fabricated devices. Collaboration: Publications:
S. Majumdar, H. S. Majumdar, D. Tobjörk, and R. Österbacka, Towards printed magnetic sensors based on organic diodes, Physica Status Solidi: A (2009)
Adjustable packaging line of the future
Main funding: EAKR, Development programs. Participating FunMat unit: DPh Daniel Tobjörk and Ronald Österbacka The packaging business is considered to have significant growth potential in the near future. At present, fiber‐based packaging materials are considered to have great potential in terms of packaging technologies, and to provide opportunities that should be seized as soon as possible. The “Adjustable packaging line of the future” projects are to develop and construct a new type of flexible manufacturing system platform for the manufacturing of paperboard packages. The project concentrates on improving the conventional production process of paperboard packaging manufactured by pressing so that it is a competitive alternative to other packaging solutions – mainly plastic and aluminum ones. The packaging market is growing rapidly in the industrialized world as families become smaller, and in the developing world due to the strong growth of the middle class. The turnover of the global packaging market is approximately 500 million dollars a year, which is six times the amount of Finnish exports annually. Forecasts indicate that the packaging market will continue to expand in the coming years. The need for manufacturing system improvement is evident because food products companies have turned to Finnish paperboard producers in search of ecological packaging solutions. Manufacturers of packaging materials do not, however, have sufficient expertise to develop the manufacturing processes of packages. Therefore, exploring the possibilities to use paperboard in future innovative packaging solutions requires in‐depth academic research.
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The “Adjustable packaging line of the future” projects are a collaborative effort of the Lappeenranta University of Technology LUT Packaging Research Institute, the Åbo Akademi University Centre for Functional Materials, and the Lahti University of Applied Sciences Institute of Design. It responds to the needs of Finnish packaging research, the forest industry and paperboard converting companies by building a cross‐regional network composed of experts in material and manufacturing technologies and design from Southern Finland. The main aim of the project is to develop and construct the adjustable and modular packaging line. When the adjustable packaging line is finished, it will be a key element and research platform in the research and education involving packaging technologies at Lappeenranta University of Technology.
The overall budget of the “Adjustable packaging line of the future” projects is approximately 2.1 million
euros, of which the ERDF covers 1.4 million euros. The head of research responsible for the projects is
Juha Varis, Professor of Production Engineering at Lappeenranta University of Technology, accompanied
by Project Manager Mika Kainusalmi. Professor Ronald Österbacka is in charge of the Åbo Akademi
University sub‐project on electronic indicators, and Senior Lecturer Marja Lampainen is responsible for
the sub‐project of the Lahti Institute of Design focusing on packaging design and the industrial design of
the packaging line.
Collaboration: Production Engineering at Lappeenranta University of Technology, Lahti Institute of Design, and industrial partners Publications:
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3.2.7 Functional Materials Printing (FunPrint) Center Project leader PhD Tapio Mäkelä Main funding: Åbo Akademi Foundation Participating FunMat units: DPC, LPT, LPC, LPCC, DPh INTRODUCTION In recent years a huge interest in low cost and high speed manufacturing methods for the manufacturing of printed intelligence has surged. To realize low‐cost roll‐to‐roll production of intelligent paper‐ and plastic based products, there is also a need for development of high‐speed production techniques, but especially materials development and formulation is critical for the successful printing of the typically multilayered structures needed. Typically, the problem lies in up‐scaling of the processing. When functional, responsive materials are used as inks in applications, various printing and coating techniques are needed. The sometimes incompatible characteristics, such as solubility, viscosity etc of the individual functional materials requires different printing methods to avoid problems in multrilayer printing caused by for instance wettability and solvation. The device configurations, alignment accuracy and minimum feature sizes are parameters which play a crucial role when choosing the most suitable printing process. The target for the Functional Material Printing Center (FUNPRINT) is to demonstrate suitable roll‐to‐roll printing techniques for functional materials and devices produced within FUNMAT. The FUNPRINT hosts versatile, laboratory scale functional printing equipment for our partners. We have currently demonstrated fully printed organic electronic devices on both plastic and fibre‐based substrates. We use hot embossing/imprinting technique to manufacturing plastic devices for bio applications. As a final target in FUNPRINT we will prototype an all printed device where several functionalities will be combined in the same process. BACKGROUND As the basis of FUNPRINT, a novel continuous roll‐to‐roll manufacturing device for testing and prototyping purposes were developed. In our modular roll‐to‐roll printer (FUNPRINTER) more than five different printing units (e.g. gravure, flexo, reverse gravure coating, ink‐jets, and lamination) can be used sequentially. We can analyze the printing parameters in‐situ since speed of the web can be controlled from 0.1 meters/minute up to 20 meters/minute. This small scale roll‐to‐roll device enables us to demonstrate fully printed applications already when only a few millilitres of functional inks are available. The first printing equipment: Inkjet (A3‐sheet) system and Reverse Gravure (roll‐to‐roll) coater were purchased and installed in year 2006 as well as sheet resistivity measuring unit which is
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used for fast analyzing on conductivity from a printed web. Simultaneously, the design and manufacturing of the multifunctional roll‐to‐roll printer (FUNPRINTER) started. Furthermore, FUNPRINT has played a crucial role in demonstrating the printed devices such as nanoparticulate magnetic inks, organic field effect transistors, organic solar cells and optimized paper surfaces. These results have been reported more detail in laboratory reports IV and V. TARGETS Within FunMat, it is very important to understand the chemical and physical behavior of materials, surfaces and the printing process itself. The demonstration of the printability of high volume applications such as electronic devices, functional surfaces and different indicators are the main targets of the FUNPRINT research. For cheap, large‐scale manufacturing, roll‐to‐roll printing techniques are natural choices. Conventional roll‐to‐roll techniques such as gravure, flexographic printing and inkjet‐printing as well as coating methods such as reverse gravure, blade coating and lamination will be used in our equipment. However, other techniques such as offset, spray coating or other novel printing methods can be added later when needed. LABORATORY AND EQUIPMENT The FUNPRINT laboratory consists of 50 m2 room including 3 fume chambers where the laboratory scale Inkjet‐printer and a reverse gravure coater has been installed. Hot embossing and resistivity measurement units are installed on laboratory table. Furthermore, the novel roll‐roll FUNPRINTER has been ready to use in the beginning of 2008. During 2008 a several master‐ and postdoc students get training for using these special laboratory equipments. In the following chapters the most important laboratory equipment were shown more detailed and results in the year 2008 observed. The FUNPRINT laboratory was fully funded by Åbo Akademi University with the funds provided by the Åbo Akademi Foundation via the strong research environment program. INKJET Inkjet is one very important part of our research, both from a manufacturing point of view as well as for materials testing. Two different kinds of equipment are used for demonstrating the potential of Inkjetting functional materials: Dimatix Material Printer DMP‐2800 was installed in fume chamber and it is capable of printing A3 size substrates (Fig.1). Results from succesful ink‐jetted results are reported in the references [1‐7]. Furthermore, roll‐to‐roll suitable Inkjet from Imaje is used in FUNPRINTER for continuous all‐printed devices.
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Fig.1. Dimatix material printer (A3 size) and printed Inkjet printed Ag‐ source‐drain structures on plastic substrate. REVERSE GRAVURE COATING The principle of reverse gravure coating method is shown in Fig. 2. In the reverse gravure method, the patterned roll (e.g. gravure roll) rotates in the opposite direction to the web and “kisses” the coated surface without a backing roll. Otherwise this methods is very similar than gravure method. The small contact area between the transfer roll and web enables a good thickness control from ca 10 nm to several micrometers. The coating speed can be varied from 0.1 up to ca. 2 m/minute. In the machine (from Yasui Seiki) shown in Fig. 2 the web width is 10 cm. The reverse gravure method is used in industry to coat thin liquid films (1‐50 mm) when ink viscosities are between 1 and 2000 mPas. The dry thickness of the layer can be varied by changing the ink‐concentration, coating roll, roll speed or web speed.
Fig.2. Reverse gravure device from Yasui Seiki and an example of a roll of coated inherently conducting polyaniline on polyethylene tereftalate (PET).
During 2008 reverse gravure coating method has been used, for example coating of semiconductor layer in OFET and thermoplastic polymer on polypropylene substrates. OFET work is reported in Refs. [1‐4,8]. Furtherrmore, reverse gravure coated polymers (5 %‐wt
www.dimatix.com
www.dimatix.com
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TOPAS on toluene solution) have been used in fluidistic applications in close collaboration with VTT, DTU University and Lund University [9‐10].
Fig. 3. A schematic presentation of continuous roll‐to‐roll fluidics manufacturing process is shown. Reverse gravure technique is used to coat TOPAS layer on the web. Polymer thickness is precisely controlled in the process [10].
HOT EMBOSSING A hot embossing and small scale embossing unit was installed in the FUNPRINT laboratory in 2008. In Fig. 4 the basic principle of the hot embossing method is shown. A metal stamp is heated above the glass transition temperature of a polymer and pressed against the polymer. The pressure is kept constant while the metal stamp is cooled close to the room temperature. After this, the stamp is released and the stamp feature is transferred to the polymer.
Fig.4. Schematic presentation of hot embossing technique is shown. The heated metal stamp is pressed against the polymer layer at temperature above the glass temperature of the polymer, after which the stamp is cooled and released.
T = 25 C
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Figure 5 shows a metal stamp used in the experiments and an example of the printed well‐structure on the 1 mm thick polycarbonate film. The used temperature is 140 C, pressure ca, 8 MPa and embossing time 5 min. The printed structures will be used in the bio applications in the future.
Fig.5. A graved Al‐stamp used in the experiments (right). The stamp consist 15 well structures with a diameter of 1 mm and height of 2 mm. The printed example in polycarbonate film is shown in left.
FUNPRINTER‐DEVICE This multifunctional and modular printing device was designed to include reverse‐gravure, gravure, flexographic, lamination/calendaring and Inkjet units. The web width was adjusted to 10 cm to keep material consumption as low as possible. The printing speed can be varied from 0.1 m/minute up to ca. 20 m/minute. All printing units are placed in sequence which allows the use of different printing techniques in one printing cycle as well as interchanging of printing sequence. All units are synchronized. A schematic layout of Funprinter is seen in Fig. 6. In the year 2008, hot embossing equipment was manufactured particularly for the use in bio applications.
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Fig.6. A schematic layout of the Funprinter device is shown. This unique device consists of gravure, flexo, reverse‐gravure coating, lamination and two Inkjet units.
The basic principles of a) reverse‐gravure, b) gravure and c) flexographic units are shown in Fig. 7. The real FUNRINTER device is shown in Fig. 8.
a) b) c) Fig.6. Schematic principle of a) reverse gravure coating, b) gravure printing and flexo methods is shown.
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Fig.8. The unique roll‐to‐roll printing device (Funprinter) is shown. The speed control and inkjets are operated by a computer when pressures and temperatures are controlled manually. The order of the printing units can be changed easily for versatile printing with low material consumption.
In the year 2008 FUNPRINTER was optimized to use the roll‐to‐roll reverse gravure coating unit together with the two inkjetting units. The alignment of the two inkjet units is performed by using software controlling. Inkjet heads are shown in the figure 9 when oil based inks are used for demonstrating aligning of the two head. In the year 2009 optical camera system will be used for aligning.
Fig.9. The inkjet heads on the roll‐to‐roll printing device (Funprinter). First head contain 128 nozzles (left) and second head 512 nozzles (right). Aligning of inkjet units is performed by using inkjet controlling software and delay time therein. The roll‐to‐roll inkjet is tested by printing Carbon based ink on paper substrate.
As an example of using multiple printing units at the same time a thermocromic device (“hidden code”) is printed. Schematic principle of the printing process is shown in Fig. 10 where Inkjet 1 is used to print first layer, reverse gravure method second and inkjet 2 third layers. In the device the hidden code appears when device were heated above transition temperature
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(47 C). Thermochromic ink turns from red to transparent and also the code under the thermochromic layer becomes visual.
Fig.10. A schematic image of the continuous roll‐to‐roll manufacturing process is shown. Three different steps are used in device manufacturing: hidden code is printed on web using inkjet (Inkjet 1); web is coated with thermochromic ink using reverse gravure (RG) coating technique and finally visual layout using inkjet (Inkjet 2). The inks used in the experiment were dried right after the printing unit (dryers 1‐3) and therefore layering was possible.
Fig.11. A schematic image of the thermochromic device is shown (right). In the device the hidden code appears when device were heated above transition temperature (47 C) (left). Thermochromic ink turns from red to transparent and also the code under the thermochromic layer becomes visually readable.
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Collaboration: Future Printing Center, Hansaprint, UPM, StoraEnso, PANIPOL, TTY, VTT, DTU, LUND References (FUNPRINT related publications 2008) [1] Tobjörk, Daniel; Kaihovirta, Nikolai; Mäkelä, Tapio; Pettersson,Fredrik, Österbacka, Ronald; All‐printed low‐voltage organic transistors, Organic Electronics 9 (2008) 931‐935. [2] Kaihovirta, Nikolai; Tobjörk, Daniel; Mäkelä, Tapio; Österbacka, Ronald; Absence of substrate roughness effects on an all‐printed organic transistor operating at one volt, Applied Physics Letters 93 (2008) 053302. [3] Kaihovirta, Nikolai; Tobjörk, Daniel; Mäkelä, Tapio; Österbacka, Ronald; Low‐Voltage Organic Transistors Fabricated Using Reverse Gravure Coating on Prepatterned Substrates, Advanced Engineering Materials, 10 (7) (2008) 640‐643 [4] Tobjörk, Daniel; Aarnio, Harri; Mäkelä, Tapio; Österbacka, Ronald; Roll‐to‐Roll Fabrication of Bulk Heterojunction Plastic Solar Cells using the Reverse Gravure Coating Technique, Mater. Res. Soc. Symp. Proc. Vol. 1091 (2008). [5] Lin, J.; Pekkanen, J.; Mäntysalo; M., Mäkelä, T.; Österbacka, R; Utilization of selective patterning for inkjet printing in the electronics manufacturing, IMAPS Advanced Technology Workshop and Tabletop Exhibition on Printed Devices and Applications, Orlando, Florida, USA, February 25‐27, (2009) 5 p. [6] T. Mäkelä, Towards printed electronic devices. Large‐scale processing methods for conducting polyaniline, Doctoral thesis, VTT Publications: 67 (2008). [7] Mäkelä, Tapio; All‐printable electronic devices: towards high volume manufacturing methods, The XLII Annual Conference of the Finnish Physical Society. Turku, Finland, 27 ‐ 29 March 2008. (Invited, Plenary Lecture). [8] Kaihovirta, Nikolai; Tobjörk, Daniel; Mäkelä, Tapio; Österbacka, Ronald; An All‐printed Low‐
Voltage Organic Transistor, The 8th International Symbosium on Functional ‐Electron Systems, 21st – 25th July 2008, Graz Austria, T‐43.(Oral). [9] Larsen, Vig Asger; Mäkelä, Tapio; Majander, Päivi; Ahopelto, Jouni; Kristensen, Anders; Roll‐to‐Roll Thermal Nanoimprinted Microfluidic Separation Devices, 7th International Conference on Nanoimprint and Nanoprint Technology (NNT'08). Kioto, Japan, 13 ‐ 15 Oct. 2008. Japan Society of Applied Physics. Kioto, Japan (2008) 200–201. [10] Beech, Jason; Mäkelä, Tapio; Majander, Päivi; Tegenfeldt, Jonas; Throughput through thin‐film fluidics, µTAS2008 Conference. San Diego, California, USA, 12 ‐ 16 Oct. 2008. MicroTAS. California (2008), 1492‐1494.
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2. Publications 4.1 Theses 4.1.1 Doctoral theses Tapio Mäkelä: Towards printed electronic devices. Large‐scale processing methods for conducting polyaniline. Markus Nuopponen: Organized nanostructures of thermoresponsive poly(N‐isopropylacrylamide) block copolymers obtained through controlled RAFT polymerization. Jessica Rosenholm: Modular design of mesoporous silica materials: Towards multifunctional drug delivery systems. Mikael Stolt: Lactoyl (Co)polymers prepared by iron carboxylate catalysis. Satu Strandman: Syntheses and self‐assembling characteristics of amphiphilic star diblock copolymers.
4.1.2 Master of Science Theses Alain Duchanoy: Synthesis and controlled functionalization of (mesoporous) silica nano‐ particles. Andreas Timmerbacka: Molekylmodelleringsprogram för undervisningssyften. (Molecule modeling program for education purposes) Otto Järvinen: Modellering av bindemedel i bestrykningsskikt – algoritmer och kodoptimering (Modeling of the binding agents in paper coating – algorithms and code optimization) Andreas Lemström: Inverkan av pigmentets partikelform på egenskaperna hos bestruket papper (The effect of particle shape of the pigments on the properties of coated paper) Hong Zhai: Utilisation of mannans for surface treatment of paper Jonas Asplund: Interactions between latex and starch binders in pigment coating of paper Mikael Ek: Uppslagning av barriärbestrykta papper (Repulping of barrier coated paper) Kenneth Nylander: Evaluation of a laboratory method for paper’s dynamic compressibility and smoothness
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Daniel Lindberg: Impedansspektroskopi (Impedance spectroscopy) Mathias Nyman: En kombinerad optisk och elektrisk metod för mätning av laddningsdynamik i polymera solcellsmaterial (A combined optical and electrical method for the measurement of charge dynamics in polymeric solar cell materials) Fredrik Pettersson: Konstruktion av en Kelvin probe‐mätuppställning (Construction of a Kelvin probe measurement design) Simon Sandén: Optisk karakterisering av kiselnanopartiklar (Optical characterization of silica nano‐particles)
4.2 Articles 4.2.1 Articles in international refereed journals Justyna Sadowska, Bjarne Johansson, Espen Johannessen, Rauno Friman, Lubomira Broniarz‐Press, Jarl B. Rosenholm:”Characterization of ozonated vegetable oils by spectroscopic and chromatographic methods.” Chemistry and Physics of Lipids 2008, 151, 85‐91. Mikael Järn, Felix J. Brieler, Monica Kuemmel, David Grosso, and Mika Lindén:”Wetting of hetero‐geneous nanopatterned inorganic surfaces.” Chem. Mater. 2008, 20, 1476‐1483. Jan‐Henrik Smått, Nicolas Schüwer, Mikael Järn, Wolfgang Lindner, Mika Lindén: ”Synthesis of Micro‐meter sized mesoporous metal oxide spheres by nanocasting.” J. Micromeso 2008, 112, 308‐318. Xiaoxue Zhang, Mikael Järn, Jouko Peltonen, Viljami Pore, Tommi Vuorinen, Erkki Levänen, Tapio Mäntylä: ”Analysis of roughness parameters to specify superhydrophobic antireflective boehmite films made by the sol‐gel process.” J.Eur.Ceram.Soc. 2008, 28, 2177‐2181. Xiaoxue Zhang, Mari Honkanen, Mikael Järn, Jouko Peltonen, Viljami Pore, Erkki Levänen, Tapio Mäntylä: ”Thermal stability of the structural features in the super‐hydrophobic boehmite films on austenitic stainless steels.” Applied Surface Science 2008, 254, 5129‐5133. Juha‐Pekka Nikkanen, Helmi Keskinen, Mikko Aromaa, Mikael Järn, Tomi Kanerva, Erkki Levänen, Jyrki M. Mäkelä, and Tapio Mäntylä:”Iron oxide doped alumina‐zirconia nano‐ particle synthesis by liquid flame spray from metal organic precursors.” Research Letters in Nanotechnology 2008, doi:10.1155/ 2008/516478. C.‐M. Tåg, M. Juuti, K.‐E. Peiponen, J.B. Rosenholm:”Print mottling: Solid‐liquid adhesion related to optical appearence.” Colloids and Surfaces A: Physicochem. Eng. Aspects 2008, 317, 658‐665.
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Jessica M .Rosenholm, Alain Duchanoy, and Mika Lindén:”Hyperbranching surface polymerization as a tool for preferential functionalization of the outer surface of mesoporous silica.” Chem. Mater. 2008, 20, 1126‐1133. Lotta Bergman, Jessica Rosenholm, Anna‐Brita Öst, Alain Duchanoy, Pasi Kankaanpää, Jyrki Heino, and Mika Lindén:”On the complexity of electrostatic suspension stabilization of functionalized silica nanoparticles for biotargeting ang imaging applications.” Journal of Nanomaterials 2008, doi:10.1155/ 2008/712514. Jessica M. Rosenholm, Mika Lindén:”Towards establishing structure‐activity relationships for meso‐porous silica in drug delivery applications.” J. Controlled Release 2008, 128, 157‐164. Jarkko Leivo, Mika Lindén, Jessica M. Rosenholm, Merja Ritola, Cilâine V. Teixeira, Erkki Levänen, Tapio A. Mäntylä:”Evolution of aluminosilicate structure and mullite crystallization from homogeneous nano‐particulate sol‐gel precursor with organic additives.” J. Eur. Ceram.Soc. 2008, 28, 1749‐1762. Tanya Tsoncheva, Ljubomira Ivanova, Rayna Dimitrova, Jessica Rosenholm: ”Physico‐chemical and catalytic properties of grafted vanadium species on different mesoporous silicas.” J. Colloid and Interface Sci. 2008, 321, 342‐349. Tanya Tsoncheva, Jessica Rosenholm, Mika Lindén, Freddy Kleitz, Michael Tiemann, Ljubomira Ivanova, Momtchil Dimitrov, Daniela Paneva, Ivan Mitov, Christo Minchev: ”Critical evaluation of the state of iron oxide nanoparticles on different mesoporous silicas prepared by an impregnation method.” Microporous and Mesoporous Materials 2008, 112, 327‐337. Malin H. Sörensen, Robert W. Corkery, Jan Skov Pedersen, Jessica Rosenholm, Peter C. Alberius: ”Expansion of the F127‐templated mesostructure in aerosol‐generated particles by using polypropylene glycol as a swelling agent.” Microporous and Mesoporous Materials 2008, 113, 1‐13. N. Baccile, C.V. Teixeira, H. Amenitsch, F. Villain, M. Lindén, F. Babonneau:”Time‐Resolved in Situ Raman and Small‐Angle X‐ray Diffraction Experiments: From Silica‐Precursor Hydrolysis to Development of Mesoscopic Order in SBA‐3 Surfactant‐Templated Silica.” Chem. Mater. 2008, 20, 1161‐1172. M. Tiemann, F. Marlow, J. Hartikainen, O. Weiss, M. Linden:” Ripening Effects in ZnS Nanoparticle Growth.” J. Phys. Chem. C. 2008, 112, 1463‐1467. Thomas Sandberg, Jessica Rosenholm, Matti Hotokka: “The molecular structure of disulfiram and its complexation with silica. A quantum chemical study.” Theochem 2008, 861, 57‐61.
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J. Puputti, Q. Xu, M. Lindén,:” Inhibition of crystal growth during drying in gels derived from a cheap, mixed metal oxide precursor.” J. Sol‐Gel Sci. 2008, 47, 347‐353. Jarl B. Rosenholm, Kai‐Erik Peiponen, Evgeny Gornov:”Materials cohesion and interaction forces.” Advances in Colloid and Interface Science 2008, 141, 48‐65. Rasmus Eriksson, Juha Merta, Jarl B. Rosenholm:”The calcite/water interface II. Effect of added lattice ions on the charge properties and adsorption of sodium polyacrylate.” J. Colloid and Interface Science 2008, 326, 396‐402. Mika Harju, Mikael Järn, Per Dahlsten, Jarl B. Rosenholm, Tapio Mäntylä:”Influence of long‐term aqueous exposure on surface properties of plasma sprayed oxides Al2O3, TiO2 and their mixture Al2O3‐13TiO2.” Applied Surface Science 2008, 254, 7272‐7279. Mika Harju, Mikael Järn, Per Dahlsten, Juha‐Pekka Nikkanen, Jarl B. Rosenholm, Tapio Mäntylä: ”Influence of long‐term aqueous exposure on surface properties of plasma‐sprayed oxides Cr2O3 and Cr2O3‐25 wt% TiO2.” J. Colloid and Interface Science 2008, 326, 403‐410. Mikael Järn, Mikko Heikkilä, and Mika Lindén:”Bioinspired synthesis of superhydro‐phobic coatings.” Langmuir 2008, 24, 10625‐10628. Kaj Backfolk, Petri Sirviö, Petri Ihalainen, Jouko Peltonen:”Thermal and topographical characterization of polyester‐ and styrene/acrylate‐based composite powders by scanning probe microscopy.” Thermo‐chimica Acta 2008, 470, 27‐35. Mikael Siltanen, Elina Vuorimaa, Helge Lemmetyinen, Petri Ihalainen, Jouko Peltonen, and Martti Kauranen:”Nonlinear optical and structural properties of Langmuir‐Blodgett films of thiohelicenebisquinones.” J. Phys. Chem. B 2008, 112, 1940‐1945. Sturm Martin, Leitner Alexander, Smatt Jan‐Henrik, Linden Mika, Lindner Wolfgang: ” Tin dioxide microspheres as a promising material for phosphopeptide enrichment prior to liquid chromatography‐(tandem) mass spectrometry analysis.” Adv. Funct. Mater. 2008, 18, 2381‐2389. Boris Ufer, Jessica M. Rosenholm, Alain Duchanoy, Lotta Bergman, Mika Lindén: “Poly(ethylene imine)functionalized mesoporous silica nanoparticle for biological applications.” Zeolites and related materials – trends, targets and challenges. Ed. A. Gédéon, P. Massiani, F. Babonneeau. Elsevier. Stud. Surf. Sci. Catal., 2008, 174 A, 353‐356. Mika Lindén, Florence Babonneau, Heinz Amenitsch, Niki Baccile, Andy Riley, Sarah Tolbert:”On the mechanism of formation of SBA‐1 and SBA‐3 as studied by in situ synchrotron XRD.” Zeolites and related materials – trends, targets and challenges. Ed. A. Gédéon, P. Massiani, F. Babonneeau. Elsevier. Stud.Surf. Sci. Catal., 2008, 174 A, 103‐108.
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L. Ivanova, Jessica Rosenholm, T. Tsoncheva, Mika Lindén, D. Paneva, I. Mitov:”Iron oxide nanoparticles supported on NH2‐ and COOH‐functionalized SBA‐15.” React. Kinet.Cat.Lett. 2008, Vol. 95(2), 329‐336. Mika Harju, Sami Areva, Jarl B. Rosenholm, Tapio Mäntylä:”Characterization of water exposed plasma sprayed oxide coating materials using XPS.” Applied Surface Science 2008, 254, 5981‐5989. Marek Kosmulski:”Badania potencjału elektrokinetycznego metodą elektroakustyczną (Studies on electrokinetic potential by the electroacoustic method).” Przemysł chem. 2008, 87/4, 381‐383. Torvald Vestberg, Peter denifl and Carl‐Eric Wilén; "Porous versus Novel compact Ziegler‐Natta Catalyst Particles and Their fragmentation During the Early Stages of Bulk Propylene Polymerization" Lauri Valtola, Sami Hietala, Heikki Tenhu, Peter Denifl and Carl‐Eric Wilén" Association behaviour and properties of copolymers of perfluorooctyl ethyl methacrylate and eicosanyl methacrylate" Polym. Adv. Technol. 2008 Saara Inkinen, Mikael Stolt and Anders Södergård "Stability studies on blends of a lactic acid‐based hot melt adhesive and starch" Journal of Applied Polymer Science, Volume 110, Issue 4,2008
Andersson Toni. ; Sumela, Miika. ; Khriachtchev, Leonid: Solution properties of an aqueous poly(methacryl oxyethyl trimethylammonium chloride) and its poly(oxyethylene) grafted analog. J. Polym. Sci. Part B: Polym. Phys. 46 (2008) 547‐557 Liisa Johansson, Mikko Karesoja, Päivi Ekholm, Liisa Virkki, Heikki Tenhu: Comparison of the solution properties of (1→3),(1→4)‐β‐d‐glucans extracted from oats and barley, LWT 41 (2008) 180‐184 K. Backfolk, J. Peltonen, N. Triantafillopoulos, S. Lagerge and J.B. Rosenholm: The Influence of Lubricating Agents on the Formation of a Film of a Styrene/Butadiene Latex. Tribology Letters 29 (2008), 57‐66. K. Backfolk, P. Sirviö, P. Ihalainen and J. Peltonen: Thermal and Topographical Characterization of Polyester‐ and Styrene/Acrylate‐Based Composite Powders by Scanning Probe Microscopy. Thermochimica Acta 470 (2008), 27‐35. P. Ihalainen, K. Backfolk, P. Sirviö, and J. Peltonen: Thermal Analysis and Topographical Characterization of Films of Styrene‐Butadiene Blends. Journal of Applied Polymer Science 109 (2008), 322‐332.
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J. Järnström, P. Ihalainen, K. Backfolk and J. Peltonen: Roughness of pigment coatings and its influence on gloss. Applied Surface Science 254 (2008), 5741‐5749.
M. Raulio, M. Järn, J. Ahola, J. Peltonen, J.B. Rosenholm, S. Tervakangas, J. Kolehmainen, T. Ruokolainen, P. Narko and M. Salkinoja‐Salonen: Microbe repelling coated stainless steel analysed by field emission scanning electron microscopy and physicochemical methods. Journal of Industrial Microbiology and Biotechnology 35 (2008), 751‐760. J. Chen, A. Fallarero, A. Määttänen, M. Sandberg, J. Peltonen, P. Vuorela and M.‐L. Riekkola: Living cells of staphylococcus aureus immobilized onto the capillary surface in electrochromatography: a tool for screening of biofilms. Analytical Chemistry 80 (2008), 5103‐5109.
M. Sandberg, A. Määttänen, J. Peltonen, P. Vuorela and A. Fallarero: Automating a 96‐well microtitre plate model for Staphylococcusaureus biofilms: an approach to screening of natural antimicrobial compounds. International Journal of Antimicrobial Agents 32 (2008), 233‐240. M. Pykönen, H. Sundqvist, J. Järnström, O.‐V. Kaukoniemi, M. Tuominen, J. Lahti, J. Peltonen, P. Fardim and M. Toivakka: Effects of Atmospheric Plasma Activation on Surface Properties of Pigment‐Coated and Surface‐Sized Papers. Applied Surface Science 255 (2008), 3217‐3229. H. Härmä, L. Dähne, S. Pihlasalo, J. Suojanen, J. Peltonen and P. Hänninen: Sensitive quantitative protein concentration method using luminescent resonance energy transfer on a layer‐by‐layer europium(III) chelate particle sensor. Analytical Chemistry 80 (2008), 9781‐9786. S. Wang, J. Järnström, P. Ihalainen and J. Peltonen: The effect of base paper and coating method on the surface roughness of pigment coatings. Journal of Dispersion Science and Technology 30 (2009), 961‐968. S. Pihlasalo, M. Hara, P. Hänninen, J.P.Slotte, J. Peltonen and H. Härmä: Liposome based homogeneous luminescence resonance energy transfer. Analytical Biochemistry 384 (2009), 231‐237. A. Valanne, J. Suojanen, J. Peltonen, T. Soukka, P. Hänninen and H. Härmä: Multiple sized Europium(III) chelate‐dyed polystyrene particles as donors in FRET – an application for sensitive protein quantification utilizing competitive adsorption. Analyst 5 (2009), 980‐986. R. Bollström, A. Määttänen, D. Tobjörk, P. Ihalainen, N. Kaihovirta, R. Österbacka, J. Peltonen, M. Toivakka: A multilayer coated fiber‐based substrate suitable for printed functionality. Organic Electronics 10 (2009), 1020‐1023.
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A. Laiho, J.K. Baral, H.S. Majumdar, F. Jansson, A. Soininen, R. Österbacka, and O. Ikkala, “Influence of morphology on the electrical behavior of a polymer/fullerene composite memory device”, Applied Physics Letters 93, 203309 (2008) A. V. Nenashev, F. Jansson, S. D. Baranovskii, R. Österbacka, A. V. Dvurechenskii, and F. Gebhard ” Hopping conduction in strong electric fields: Negative differential conductivity”, Physical Review B 78, 165207 (2008). Chellappan Vijila, M. Westerling, H. Aarnio, R. Österbacka, Huang Chuna, Chen Zhikuana, Zhang Xinhaia, Zhu Furonga, and Chua Soo Jin, “Nature and dynamics of photoexcited states in an electroluminescent poly(phenylene vinylene‐co‐fluorenylene vinylene)‐based p‐conjugated polymer”, J. Photochem. Photobiol. A: Chem. 199, 358‐362 (2008) D. Tobjörk, N. J. Kaihovirta, T. Mäkelä, F. Pettersson, and R. Österbacka, ”All printed low‐voltage transistors”, Organic Electronics 9, 931‐935 (2008) N. Kaihovirta, D. Tobjörk, T. Mäkelä, and R. Österbacka, ”Absence of substrate roughness effects on an all‐printed organic transistor operating at one volt”, Applied Physics Letters 93, 053302 (2008).
F. Jansson, S. Baranovskii, F. Gebhard, and R. Österbacka, “Effective Temperature for hopping transport in a Gaussian DOS”, Physical Review B 77, 195211 (2008).
N. Kaihovirta, D. Tobjörk, T. Mäkelä, and R. Österbacka, ” Low‐Voltage Organic Transistors Fabricated using Reverse Gravure Coating on Prepatterned Substrates”, Advanced Engineering Materials, 10, 640 (2008). D. Wei, J. K. Baral, R. Österbacka, and A. Ivaska, ” Electrochemical fabrication of nonvolatile memory device based on polyaniline and gold particles”, Journals of Materials Chemistry, Journal of Materials Chemistry, 18, 1853 ‐ 1857 (2008). D. Wei, J. K. Baral, R. Österbacka, and A. Ivaska, ”Memory effect in IL matrix containing single walled carbon nanotubes and polystyrene”, Nanotechnology 19, 055203(2008) J. K. Baral, H. S. Majumdar, A. Laiho, H. Jiang, E.I,. Kauppinen, R. H. A. Ras, J. Ruokolainen, O. Ikkala, and R. Österbacka, ”Organic memory using the fullerene‐derivative [6,6]‐phenyl‐C61 butyric acid methyl ester (PCBM): Morphology, thickness and concentration dependence studies”, Nanotechnology 19, 035203 (2008). Shan, Jun; Zhao, Yiming; Granqvist, Niko; Tenhu, Heikki: Thermoresponsive Properties of N‐Isopropylacrylamide Oligomer Brushes Grafted to Gold Nanoparticles: Effects of Molar Mass and Gold Core Size, Macromolecules (Washington, DC, United States) (2009), 42(7), 2696‐2701.
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Pulkkinen, Petri; Shan, Jun; Leppänen, Kirsi; Kansakoski, Ari; Laiho, Ari; Järn, Mikael; Tenhu, Heikki: Poly(ethylene imine) and Tetraethylenepentamine as Protecting Agents for Metallic Copper Nanoparticles, ACS Applied Materials & Interfaces (2009), 1(2), 519‐525. Shan, Jun; Pulkkinen, Petri; Vainio, Ulla; Maijala, Juha; Merta, Juha; Jiang, Hua; Serimaa, Ritva; Kauppinen, Esko; Tenhu, Heikki: Poly(ethylene imine) and Tetraethylenepentamine as Protecting Agents for Metallic Copper Nanoparticles, Journal of Materials Chemistry (2008), 18(27), 3200‐3208. Camila A. Rezende, Jun Shan, Lay‐Theng Lee, Gilbert Zalczer and Heikki Tenhu: Tuning the structure of thermosensitive gold nanoparticle monolayers, The Journal of Physical Chemistry B, 2009, 113 (29), 9786–9794 Jun Zhao, Jun Shan, Guy Van Assche, Heikki Tenhu and Bruno Van Mele: Demixing and Remixing Kinetics in Aqueous Dispersions of Poly(N‐isopropylacrylamide) (PNIPAM) Brushes Bound to Gold Nanoparticles Studied by Means of Modulated Temperature Differential Scanning Calorimetry, Macromolecules, 2009, 42 (14), 5317–5327 Karesoja, Mikko; Jokinen, Harri; Karjalainen, Erno; Pulkkinen, Petri; Torkkeli, Mika; Soininen, Antti; Ruokolainen, Janne; Tenhu, Heikki: Grafting of montmorillonite nano‐clay with butyl acrylate and methyl methacrylate by atom transfer radical polymerization: Blends with poly(BuA‐co‐MMA), Journal of Polymer Science, Part A: Polymer Chemistry (2009), 47(12), 3086‐3097. Plamper, Felix A.; McKee, Jason R.; Laukkanen, Antti; Nykänen, Antti; Walther, Andreas; Ruokolainen, Janne; Aseyev, Vladimir; Tenhu, Heikki: Miktoarm stars of poly(ethylene oxide) and poly(dimethylaminoethyl methacrylate): manipulation of micellization by temperature and light, Soft Matter (2009), 5(9), 1812‐1821.
Hietala, Sami; Strandman, Satu; Järvi, Paula; Torkkeli, Mika; Jankova, Katja; Hvilsted, Soren; Tenhu, Heikki: Rheological Properties of Associative Star Polymers in Aqueous Solutions: Effect of Hydrophobe Length and Polymer Topology, Macromolecules (2009), 42(5), 1726‐1732. Strandman, Satu; Zarembo, Anna; Darinskii, Anatoly A.; Laurinmäki, Pasi; Butcher, Sarah J.; Vuorimaa, Elina; Lemmetyinen, Helge; Tenhu, Heikki: Effect of the Number of Arms on the Association of Amphiphilic Star Block Copolymers, Macromolecules (2008), 41(22), 8855‐8864.
Larin, Sergey; Lyulin, Sergey; Lyulin, Alexey; Darinskii, Anatoly: Computer simulations of interpolyelectrolyte complexes formed by star‐like polymers and linear polyelectrolytes, Macromolecular Symposia (2009), 278(Molecular Order and Mobility in Polymer Systems), 40‐47.
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Lyulin, Sergey; Karatasos, Kostas; Darinskii, Anatolij; Larin, Sergey; Lyulin, Alexey: Structural effects in overcharging in complexes of hyperbranched polymers with linear polyelectrolytes, Soft Matter (2008), 4(3), 453‐457. Vihola, Henna; Laukkanen, Antti; Tenhu, Heikki; Hirvonen, Jouni: Drug release characteristics of physically cross‐linked thermosensitive poly(N‐vinylcaprolactam) hydrogel particles, Journal of Pharmaceutical Sciences (2008), 97(11), 4783‐4793. Nuopponen, Markus; Kalliomäki, Katriina; Aseyev, Vladimir; Tenhu, Heikki: Spontaneous and Thermally Induced Self‐Organization of A‐B‐A Stereoblock Polymers of N‐Isopropylacrylamide in Aqueous Solutions, Macromolecules (2008), 41(13), 4881‐4886. Nykänen, Antti; Nuopponen, Markus; Hiekkataipale, Panu; Hirvonen, Sami‐Pekka; Soininen, Antti; Tenhu, Heikki; Ikkala, Olli; Mezzenga, Raffaele; Ruokolainen, Janne: Direct Imaging of Nanoscopic Plastic Deformation below Bulk Tg and Chain Stretching in Temperature‐Responsive Block Copolymer Hydrogels by Cryo‐TEM, Macromolecules (2008), 41(9), 3243‐3249. Hietala, Sami; Nuopponen, Markus; Kalliomäki, Katriina; Tenhu, Heikki: Thermoassociating Poly(N‐isopropylacrylamide) A‐B‐A Stereoblock Copolymers, Macromolecules (2008) 41(7), 2627‐2631. Kjoniksen, Anna‐Lena; Laukkanen, Antti; Tenhu, Heikki; Nyström, Bo: Anomalous turbidity, dynamical, and rheological properties in aqueous mixtures of a thermoresponsive PVCL‐g‐C11EO42 copolymer and an anionic surfactant, Colloids and Surfaces, A: Physicochemical and Engineering Aspects (2008), 316(1‐3), 159‐170. Valtola, Lauri; Hietala, Sami; Tenhu, Heikki; Denifl, Peter; Wilen, Carl‐Eric: Association behavior and properties of copolymers of perfluorooctyl ethyl methacrylate and eicosanyl methacrylate, Polymers for Advanced Technologies (2009), 20(3), 225‐234. Huhtinen, Petri; Kivelä, Mirja; Soukka, Tero; Tenhu, Heikki; Lövgren, Timo; Härma, Harri: Preparation, characterisation and application of europium(III) chelate‐dyed polystyrene‐acrylic acid nanoparticle labels, Analytica Chimica Acta (2008), 630(2), 211‐216.
Tarabukina, E. B.; Krasnov, I. L.; Tarasova, E. V.; Ratnikova, O. V.; Melenevskaya, E. Yu.; Filippov, A. P.; Laukkanen, A.; Aseev, V. O.; Tenhu, H: The effect of the centrifugal force on the molecular characteristics of polyvinylcaprolactam complexes with fullerene C60, Vysokomolekulyarnye Soedineniya, Seriya A i Seriya B (2008), 50(2), 315‐323. Krasnou, Illia; Tarabukina, Elena; Melenevskaya, Elena; Filippov, Alexander; Aseyev, Vladimir; Hietala, Sami; Tenhu, Heikki: Rheological Behavior of Poly(vinylpyrrolidone)/Fullerene C60 Complexes in Aqueous Medium, Journal of Macromolecular Science, Part B: Physics (2008), 47(3), 500‐510.
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Andersson, Toni; Sumela, Miika; Khriachtchev, Leonid; Räsänen, Markku; Aseyev, Vladimir; Tenhu, Heikki: Solution properties of an aqueous poly(methacryl oxyethyl trimethylammonium chloride) and its poly(oxyethylene) grafted analog, Journal of Polymer Science, Part B: Polymer Physics (2008), 46(6), 547‐557. Matilainen, Laura; Maunu, Sirkka Liisa; Pajander, Jari; Auriola, Seppo; Jääskeläinen, Ilpo; Larsen, Kim Lambertsen; Järvinen, Tomi; Jarho, Pekka: The stability and dissolution properties of solid glucagon/γ‐cyclodextrin powder, European Journal of Pharmaceutical Sciences (2009), 36(4‐5), 412‐420. Hoppu, Pekka; Hietala, Sami; Schantz, Staffan; Juppo, Anne Mari: Rheology and molecular mobility of amorphous blends of citric acid and paracetamol, European Journal of Pharmaceutics and Biopharmaceutics (2009), 71(1), 55‐63. Raula, Janne; Thielmann, Frank; Kansikas, Jarno; Hietala, Sami; Annala, Minna; Seppälä, Jukka; Lähde, Anna; Kauppinen, Esko I: Investigations on the Humidity‐Induced Transformations of Salbutamol Sulphate Particles Coated with L‐Leucine, Pharmaceutical Research (2008), 25(10), 2250‐2261. Lintinen, Kalle; Efimov, Alexander; Hietala, Sami; Nagao, Shijo; Jalkanen, Pasi; Tkachenko, Nikolai; Lemmetyinen, Helge: Cationic photopolymerization of liquid fullerene derivative under visible light, Journal of Polymer Science, Part A: Polymer Chemistry (2008), 46(15), 5194‐5201. Uschanov, Pirita; Heiskanen, Nina; Mononen, Pekka; Maunu, Sirkka Liisa; Koskimies, Salme: Synthesis and characterization of tall oil fatty acids‐based alkyd resins and alkyd‐acrylate copolymers, Progress in Organic Coatings (2008) 63(1), 92‐99. Virtanen, Tommi; Maunu, Sirkka Liisa; Tamminen, Tarja; Hortling, Bo; Liitia, Tiina: Changes in fiber ultrastructure during various kraft pulping conditions evaluated by 13C CPMAS NMR spectroscopy, Carbohydrate Polymers (2008), 73(1), 156‐163.
4.2.2 Books and book chapters
Jarl B. Rosenholm and Mika Lindén:”Controlled synthesis and processing of ceramic oxides – A molecular approach.” Handbook of Surface and Colloid Chemistry. Third edition. Ed. K.S. Birdi 2008, CRC Press, pp. 439‐497. Maunu, Sirkka Liisa: 13C CPMAS NMR studies of wood, cellulose fibers, and derivatives, Edited by Hu, Thomas Q, Characterization of Lignocellulosic Materials (2008), 227‐248.
Laukkanen, Antti; Tenhu, Heikki: Thermally responsive polymers with amphiphilic grafts: smart polymers by macromonomer technique. From Smart Polymers: Applications in Biotechnology
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and Biomedicine (2nd Edition) Edited by Galaev, Igor; Mattiasson, Bo 2008, CRC Press, pp. 115‐136.
4.2.3 Articles in refereed international edited volumes and conference proceedings
G. Sliauzys, G. Juška, K. Arlauskas, K. Genevicius, G. Dennler, and R. Österbacka, ” Charge polarization in annealed bulk‐heterojunction solar cells”, Proceedings of E‐MRS 2007, Thin Solid Films 516, 7230‐7233 (2008). D. Tobjörk, H. Aarnio, T. Mäkelä, and R. Österbacka, “Roll‐to‐Roll Fabrication of Bulk Heterojunction Plastic Solar Cells using the Reverse Gravure Coating Technique”, Mater. Res. Soc. Symp. Proc, 1091, 1091‐AA05‐45 (2008) A. Laiho, J. K. Baral, H. S. Majumdar, D. Tobjörk, J. Ruokolainen, R. Österbacka, and O. Ikkala, ” Imaging and elemental analysis of polymer/fullerene nanocomposite memory devices”, Mater. Res. Soc. Symp. Proc, 1071, 1071‐F04‐04 (2008) G. Juska, K. Genevicius, G. Sliauzys, N. Nekrasas, and R. Österbacka, ”Double injection in organic bulk‐heterojunction solar cells”, in press in proc. ICANS‐22, to appear in J. Non crystalline Solids (2008)
F. Jansson and R. Österbacka, “Simulation of Double injection in a bulk‐heterojunction material using the Gaussian disorder model”, Phys. Stat. Sol. (c) 5, No. 3, 755 ‐ 758 (2008). F. Jansson, S. D. Baranovskii, G. Sliauzys, R. Österbacka, and P. Thomas, “Effective temperature for hopping transport in a Gaussian DOS”, Phys. Stat. Sol. (c) 5, No. 3, 722 ‐ 724 (2008). DOI 10.1002/pssc.200777567 D. Tobjörk, N. J. Kaihovirta, T. Mäkelä and R. Österbacka, “All‐printed low‐voltage polymer thin film transistor by using Ink‐jet and reverse gravure techniques”,Abstract presented at the International Conference on Organic Electronics 2008, June 16‐18, 2008, Eindhoven, nr.35. N. Björklund, R. Österbacka, ”Gate dielectrics for roll‐to‐roll compatible low‐voltage organic thin film transistors”. Abstract presented at the 8th International Symposium on Functional Pi‐Electron Systems, 21‐25 Juli 2008, Graz University of Technology, Graz, Austria. Abstract book p‐145. N. Björklund, R. Österbacka,”Gate dielectrics for roll‐to‐roll compatible organic thin film transistors”. Abstract presented at the International Conference on Organic Electronics, 16 – 18 Juni 2008, Philips High Tech Campus, Eindhoven, the Netherlands. Abstract book, abstract 3.
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S. Majumdar, H. S. Majumdar, H. Aarnio, R. Laiho And R. Österbacka, “Magnetoresistance in bulk heterojunction solar cells”, Abstracts of the American Physical Society March Meeting, March 2008, New Orleans, USA. H.S. Majumdar, J.K. Baral, A. Laiho, R.H.A. Ras, F. Jansson, J. Ruokolainen, H. Jiang, E. Kauppinen, O. Ikkala, R. Osterbacka “Organic memory devices using the negative differential resistance effect” American Physical Society March Meeting, March 2008, New Orleans, USA. S. Wang, R. Mahlberg, S. Jämsä, J. Mannila, J. Nikkola, and J. Peltonen: Surface characteristics of pine and heat‐treated spruce modified with alkoxysilanes by sol‐gel process. In Proceedings of the 6th international woodcoatings congress (2008). J. Preston, R. Bollström, K. Nylander, M. Toivakka, and J. Peltonen: A new test method to measure dynamic contact in a printing nip for rotogravure papers. In Advances in Printing and Media Technology, Proceedings of the 35th International Research Conference of iarigai (2008).
M. Pykönen, H. Silvaani, J. Preston, P. Fardim, and M. Toivakka, Influence of Plasma Activation on Absorption of Ink Components and Dampening Water in Sheet‐Fed Offset Printing, In Proceedings of 35th International Research Conference, Advances in Printing and Media Technology, 2008. P. Alam, S. Mathur, T. Byholm, O., Järvinen, J. Kniivilä, and M. Toivakka, A theoretical approach to understanding microstructure‐tensile modulus relations in paper coatings In Proceedings of 2008 TAPPI 10th Advanced Coating Fundamentals Symposium. TAPPI Press, Atlanta GA, 2008.
P. Alam, S. Mathur, T. Byholm, O. Järvinen, J. Kniivilä, and M. Toivakka, Micromechanics of high porosity particle‐polymer composites, In Proceedings of the 2nd International Conference on Heterogeneous Material Mechanics, 2008.
J. Preston, M.Toivakka and P. Heard, Visualisation, Modelling and Image Analysis of Coated Paper Microstructure: Particle Shape – Microstructure Interrelations, in Proceedings of the 2nd International Papermaking and Environment Conference, p. 819‐832, Tianjin, China, 2008.
P.Salminen, R. Carlsson, S. Sandås, M. Toivakka, P. Alam and J. Roper, Combined Modeling And Experimental Studies To Optimize The Balance Between Fold Crack Resistance And Stiffness For Multilayered Paper Coatings ‐ Part 1: Introduction And Modeling Studies, In Proceedings of TAPPI Coating and Graphic Arts Conference, TAPPI Press, Atlanta GA, 2008. P. Salminen, R. Carlsson, S. Sandås, M. Toivakka, P. Alam and J. Roper, Combined Modeling And Experimental Studies To Optimize The Balance Between Fold Crack Resistance And Stiffness For Multilayered Paper Coatings ‐ Part 2: Pilot Coater Experimental Studies, In Proceedings of TAPPI Coating and Graphic Arts Conference, TAPPI Press, Atlanta GA, 2008.
H. Koivula, D.W. Bousfield and M. Toivakka, Use of Confocal Laser Scanning Microscope and Computer Model to Understand Ink Cavitation and Filamentation, In Proceedings of TAPPI Coating and Graphic Arts Conference, TAPPI Press, Atlanta GA, 2008.
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A. Sand, M. Toivakka, and T. Hjelt, Coating Layer Consolidation and the Influence of Drying Strategy ‐ A Numerical Study, in Progress in Paper Physics Seminar, Espoo, Finland, Series B, pp. 65‐68, 2008. A. Sand, M. Toivakka, and T. Hjelt, Small Particle Migration Mechanisms in Consolidating Pigment Coating Layers, in Proceedings of TAPPI 10th Advanced Coating Fundamentals Symposium, pp. 289‐298, TAPPI Press, Atlanta GA, 2008.
4.3 Åbo Akademi reports
Rosenholm Jarl och Luojola Christina (eds.):”Graduate School of Materials Research. Yearbook 2007.” ISSN 1239‐8608. Rosenholm Jarl och Luojola Christina (eds.): “Graduate School of Materials Research. Courses 2008/09.” Hotokka Matti och Luojola Christina (eds.):”Department of Physical Chemistry. Yearbook 2007.” Rosenholm Jarl och Luojola Christina (eds.): FunMat/Annual Report 2006‐07. ISSN 1797‐2965.
4.4 Patents and patent applications
Roth, Michael; Pfaendner, Rudolf; Wilen, Carl‐Eric; Aubert, Melanie, “Symmetric azo compounds in flame retardant compositions”WO2008101845 Österbacka, R.; Wilen, C‐E.; Bäcklund, T; Kaihovirta, N. ”An organic field‐effect transistor” PCT Int. Appl. (2008), 45pp. CODEN: PIXXD2 WO 2008090257. Österbacka, R.; Wilen, C‐E.; T.Mäkelä, T; Kaihovirta, N. Wikman C‐J. ” confidential patent application"
Tenhu, Heikki; Hirvonen, Sami‐Pekka; Hartikainen, Juha: Conductive polymer compositions and method for the production thereof , PCT Int. Appl. (2008), WO 2008006945 A1 20080117. Maijala, Juha; Merta, Juha; Shan, Jun; Tenhu, Heikki: Novel particles and method of producing the same, PCT Int. Appl. (2009), WO 2009040479 A1 20090402
Bollström R., Määttänen A., Ihalainen P., Peltonen J., Toivakka M.: PCT paptent application no. 20095089, 2009.
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3. Visits and visitors
5.1 Visitors to FunMat Aubert Melanie, France Bazin Damien, France Bonaboina Balakrishna, India Dahlsten Per, Sweden Duanmu Jie, China Duchanoy Alain, France He Ning, China He Xuehan, China Khajehein Mohammed, Iran Kosmulski Marek, Poland Liu Yang, China Lloret Noémie, France Maddox Franchessa, USA Majumdar Himadri, India Majumdar Sayani, India Nasir Zeeshan, Pakistan Pawelec Weronica, Poland Prochniak Piotr, Poland Salas Jeremy, France Sarfraz Jawad, Pakistan Ufer Boris, Germany Wiktorowicz Szymon, Poland Ziolowski Bartosz, Poland Xu Qian, China
5.2 Visitors from FunMat Jansson Fredrik, Germany Koivula Hanna, USA Lindén Mika, France Orava Eeva, Great Britain Pykönen Maiju, Sweden and Belgium Smått Jan‐Henrik, USA Strandman Satu, Canada
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4. Outreach
Radio 5.2. Pravda radio, Interview with J. Rosenholm at FunMat workshop 20.3. YLE‐Radio (Saara Malila, FunMat presentation) 20.3. YLE‐Areena (Saara Malila, FunMat presentation) 20.3. Lounais‐Suomen uutiset, Interview with J. Peltonen, T. Mäkelä and J.B. Rosenholm, “Älykkyyttä pakkausmateriaaleihin” 20.3. Radio Vega, Interview with J. Peltonen, T. Mäkelä and J.B. Rosenholm,“Intelligenta
förpackningar” 21.4. YLE‐Svenska Nyheter (Linus Hoffman, FunMat presentation) Television 21.2. Turku‐TV, Interview with M. Toivakka, “Role of university education and research for the future of Finnish paper industry” 22.2. YLE TV2, Interview with M. Toivakka “Future directions for the Finnish paper industry” 20.3. Lounais‐Suomen uutiset Interview with J. Peltonen, T. Mäkelä and J.B. Rosenholm “Älykkyyttä pakkausmateriaaleihin” 22.3. Ylen uutiset, Interview with J. Peltonen, T. Mäkelä and J.B. Rosenholm“Älykkyyttä pakkausmateriaaleihin”. 22.4. TV‐Nytt, Interview with J. Peltonen, T. Mäkelä and J.B. Rosenholm,“Intelligenta förpackningar”. Newspapers 22.2 Turun Sanomat, Interview with M. Toivakka: “Metsäteollisuus pelkää osaajapulaa” 22.2 Åbo Underrättelser, Interview with M. Toivakka:“Intelligens skall rädda pappers‐
industrin” 12.4 Turun Sanomat, Jarkko Saarinen’s article on Nanotechnology in “Pienestä versoo iso
bisnes” 15.5 Turun Sanomat, Jarkko Saarinen’s article on Nanotechnology “Pienen mittakaavan nanotekniikka ‐ peikko vai pelastus?” 24.4. Åbo Underrättelser, Linda Granback, Industrin tar över forskningen 9.5. www.tietysti.fi, Ulla Willberg, Transistori painettiin paperille! Ulla Willberg, Älypaperi mullistaa pakkaukset ja aikakausilehdet 16.5. Turun sanomat, Elintarvikepakkaus ilmoittaa pian itse viimeisestä käyttöpäivästä, talous, toimittaja Timo Anttila 5/08 Prosessori (www.prosessori.fi); News: Ensimmäisiä alan väitöksiä: Polyaniliini taipuu
painettuun elektroniikkaan, http://www.prosessori.fi/uutiset/uutinen2.asp?id=51983 2008 Prosessori, H. Sandberg, M. Vilkman, A. Laiho, and R. Österbacka, ”Orgaanisen
nanokomposiitin käyttö painettavassa muistipiirissä”,
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Other publications Suomen Akatemia, Kansallinen tutkimuksen huippuyksikköohjelma, Funktionaalisten materiaalien huippuyksikkö, Suomalaisen tutkimuksen kärjessä (p. 9). Vetenskapens fronter, Jarl B. Rosenholm and Mika Lindén, Funktionella material fyller alltid ett uttalat behov
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