nanoPT2014 abstracts book

Index

Foreword Page 1

Organisers/Sponsors/Committees Page 2

Exhibitors Page 3

Speakers Page 8

Abstracts Page 16

Posters List Page 97

n a n o P T 2 0 1 4 P o r t o ( P o r t u g a l ) | 1

Foreword

We take great pleasure in welcoming you to Porto (Portugal) for the 2

nd edition of the nanoPT

International Conference (nanoPT2014).

The second edition will be held with the purpose of strengthen ties nationally and internationally on

Nanotechnology and, pretends to be a reference in Portugal in the upcoming years. This conference will

encourage industry and universities working on the Nanotechnology field to know each other and to

present their research, allowing new collaborations between nearby countries such as Spain and France.

nanoPT 2014 will let participants to present a broad range of current research in Nanoscience &

Nanotechnology, not only the most prominent investigations/studies in Portugal but from all over the

World.

We are indebted to the following Institutions for their financial support: Viajes El Corte Inglés,

International Iberian Nanotechnology Laboratory (INL) and FEI.

We would also like to thank the following companies and institutions for their participation: SOQUIMICA,

Fritsch, Oerlikon Leybold Vacuum, Innova Scientific, Norleq, Particle Metrix, Panalytical, nanoVALOR,

ScienTec Ibérica and Paralab.

In addition, thanks must be given to the staff of all the organising institutions whose hard work has helped

planning this conference.

Organisers

2| n a n o P T 2 0 1 4 P o r t o ( P o r t u g a l )

Sponsors

Committees

O r g a n i z i n g C o m m i t t e e

Antonio Correia Phantoms Foundation (Spain)

Braz Costa CITEVE/CENTI (Portugal)

Jose Rivas INL (Portugal)

Vasco Teixeira Univ. Minho (Portugal)

S c i e n t i f i c C o m m i t t e e

Jean-Pierre Aimé UMR 5248 CBMN CNRS - Universite Bordeaux (France)

Stephan Roche ICN2 (Spain)

Juan José Sáenz UAM (Spain)

T e c h n i c a l C o m m i t t e e

Viviana Estêvão Phantoms Foundation (Spain)

Jose Luis Roldán Phantoms Foundation (Spain)


Exhib itors

S O Q U I M I C A

Since 1929, SOQUIMICA commercializes high quality laboratory equipment and provides highly

specialized services to its customers. We offer our clients the expertise of a qualified and

experienced team, which enables support for the development of tailor-made solutions. The

equipment we sell and the services we provide allow our customers to enjoy the best solutions

for various Applications (Chemical analyzes, Gas and liquid chromatography, Spectroscopy,

Genomics, Life sciences, Laboratory Weighing, Industrial Weighing, Preparation of samples) and

Industries (Environment, Forensics and Toxicology, Energy & Chemicals, Food Industry and

Agriculture, Pharmaceuticals and Biotechnology Industry, Textile Industry, Inspection of products

and materials testing, Clinical research, Refinery & Petrochemicals).

www.soquimica.pt

4 | n a n o P T 2 0 1 4 P o r t o ( P o r t u g a l )

O e r l i k o n

Oerlikon is a worldwide leading high-tech industrial group, specialized in mechanical and

industrial engineering. Oerlikon Leybold Vacuum is the vacuum part of the Oerlikon Group.

We offer a wide range of advanced vacuum solutions for research purposes and analytical

processes, as well as for manufacturing processes. The company's core capabilities center on the

development of application and customer specific systems for the creation of vacuum and

extraction of process gases.

Oerlikon Leybold Vacuum's ability to meet highest requirements of most complex applications

gives our customers the competitive edge to succeed. High duty processes in metallurgy, clean-

room conditions at worldwide renowned institutes for research and development, or coating

applications of minute dimensions – Oerlikon Leybold Vacuum offers highest performance.

Oerlikon Leybold Vacuum established its subsidiary in Spain in 1964.

www.oerlikon.com/leyboldvacuum/spain/es

I n n o v a S c i e n t i f i c

Innova Scientific is a company dedicated to the distribution market of laser technology and other

photonics devices in Spain and Portugal. It works with the market leaders in all the photonics

areas and offers a big deal of experience in many fields. A group of highly specialized

professionals will offer you advice and will give you the best solution for your application.

We think that our best presentation card is the number of sophisticated installations we have

carried out in many institutions in our territory during the past years.

It is in our interest to offer the best technical solution to our customers as well as the best

customer service.

All you need for your laser application.

www.innovasci.com


N o r l e q

Norleq is a recently born company counting already with various partners, most of them with a

long presence in the market, working in the area of quality control and research with several

universities and industries. Company offers products in the nanotechnology field for particle

sizing, microcalorimetry and free energy surfaces among others.

We will be exhibiting instruments from our partner Particle-Metrix that presents a new

technology for measuring particle size with some advantages over others, including the ability to

discriminate agglomerates at the nanometer level, possibility of measurement of sample

quantities in the order of a few milliliters, and simultaneously measuring the potential zeta. The

company also has in its portfolio imaging techniques.

www.norleq.com

P A N a l y t i c a l

PANalytical is the world’s leading supplier of analytical instrumentation and software for X-ray

diffraction (XRD) and X-ray fluorescence spectrometry (XRF), with more than half a century of

experience. The materials characterization equipment is used for scientific research and

development, for industrial process control applications and for semiconductor metrology.

PANalytical, founded in 1948 as part of Philips, employs around 1000 people worldwide. Its

headquarters are in Almelo, the Netherlands. Fully equipped application laboratories are

established in Japan, China, the USA, and the Netherlands. PANalytical’s research activities are

based in Almelo (NL) and on the campus of the University of Sussex in Brighton (UK). Supply and

competence centers are located on two sites in the Netherlands: Almelo (development and

production of X-ray instruments) and Eindhoven (development and production of X-ray tubes). A

sales and service network in more than 60 countries ensures unrivalled levels of customer

support. PANalytical is part of Spectris plc, the productivity-enhancing instrumentation and

controls company.

www.panalytical.com


n a n o V A L O R

Nanotechnology is the common denominator that gathers eight institutions, from the euro-

region Galicia-Northern Portugal, around Nanovalor, a project funded by the ERDF through the

Programa Operativo de Cooperación Transfronteiriza España-Portugal 2007-2013 (POCTEP).

The main goal is to strengthen institutional collaborative ties between key players’ organisations.

Apart from INL (International Iberian Nanotechnology Laboratory) the project includes the

Universidade de Minho (coordinator) TecMinho, Inesc Porto and Universidade do Porto, from

Northern Portugal, and Universidad de Santiago de Compostela, Fundación Empresa-

Universidade Galega, Asociación de Investigación Metalúrxica do Noroeste from Galicia.

www.nanovalor.org

S c i e n T e c I b e r i c a

ScienTec Ibérica, is the spanish branch of ScienTec France, its mission is to serve and attend the

Iberian Nano-micro surface analysis market from its office in Madrid.

With more than 10 years experience in Nanotechnology, our sales engineers will help you define

the right tool and configuration, our application group will teach and help you run the machines

and our after sales team will preventively maintain or repair your systems.

Your investment will be back up with a perfect combination of top level instruments with the

know-how and tool expertise in the distribution.

By characterization at ScienTec we mean:

- Scanning Probe Microscopies from CSInstruments and Agilent Technologies

- FESEM and NanoIndentaion from Agilent Technologies

- SNOM and AFM+RAMAN from Nanonics

- DHM from Lyncée Tec

- Profilometry from KLA Tencor

- Thin Film thickness from Filmetrics

- Accesories and SPM consumables

[email protected]

www.scientec.es


P A R A L A B

PARALAB was founded in 1992 by a group of young entrepreneurs. The objective was to establish

a new company on the field of distribution of scientific instrumentation, whose excellence of the

proposed technical solutions, the strong commitment for superior after sales support and

customer training, would differentiate it from all competitors. Since then, PARALAB became a

reference in the Portuguese market for:

− distribution of analytical instrumentation for laboratory and process applications

− system integration of solutions for laboratory and process applications

PARALAB has all the resources to maintain the level of support that its customer´s growing

expectations currently demand. PARALAB´s Commercial Area has four divisions:

− Analytical equipment

− General Laboratory Equipment

− Process and environmental Equipment

− Industrial Equipment

Tel: +351 224664320

Fax: +351 224664321

www.paralab.pt

[email protected]

Speakers


Index alphabetical order

K: Keynote Speakers

O: Orals (Plenary Session)

OP: Orals (Parallel Session)

Speakers

Page

Aizpurua, Javier (CFM, CSIC - UPV/EHU and DIPC, Spain)

“Optoelectronic response of quantum emitters in plasmonic nanogaps” K 17

Alcón, Natividad (AIDO, Spain)

“The Life Cycle of Nanomaterials; Current legislation and waste management issues” O 18

Alkan Olsson, Johanna (Centre for Environmental and Climate Research, Lund U., Sweden)

“Different perspectives on handling uncertainties in nanotechnology: Lessons from the

natural resource management area?” OP 19

Alonso Gomez, Jose Lorenzo (Universidad de Vigo, Spain)

“Up-standing Chiral Architectures through Topological Self-Assembly of Enantiopure Allenes” O 21

Benavente, Juana (Universidad de Málaga, Spain)

“Influence of effective membrane fixed charge on electrolyte concentration-polarization in

nanoporous alumina membranes with similar pore size” OP 23

Bernardo, Cesar (Centro de Física, Portugal)

“Exciton migration in self-assembled dendrite-type fractal superstructures of

monodisperse Quantum Dots” OP 25

Bodelon, Gustavo (University of Vigo, Spain)

“Multifunctional Au@pNIPAM Microgels for detection of EGFR by Surface-Enhanced

Resonance Raman Spectroscopy (SERRS)” O 27

Carneiro, Joaquim (University of Minho, Portugal)

“Development of a prototype based on TiO2 coated textile substrates with photocatalytic

and self- cleaning properties” O 28

Cayssol, Jérôme (Bordeaux University, France)

“New topological phases in strained graphene” O 29

Charlier, Jean-Christophe (UCL, Belgium)

“Electronic transport in N-doped graphene and in atomic carbon chains” K 30

de la Prida Pidal, Victor Manuel (Universidad de Oviedo, Spain)

“Development of electrostatic nanocapacitors by atomic layer deposition on nanostructured

materials for energy storage” O 32

Ferreira, Aires (National University of Singapore, Singapore)

“Extrinsic spin Hall effect in graphene” O 34

Figueiredo, António (Universidade de Aveiro, Portugal)

“Thermal Activate Concrete Slabs with Microencapsulated PCM: Mechanical and Thermal

Characterization” OP 35

Fortunato, Elvira (CENIMAT-I3N, Portugal)

“Thin film transistors based on metal oxide semiconductor thin films and nanoparticles” K 37

Giannakopoulos, Angelos (Laboratory Chemistry of Novel Materials, UMONS, Belgium)

“Workfunction Tuning of Graphene with Organic Molecules” OP 38

Gomes, João (ISEL, Portugal)

“Notice on a methodology for monitoring ultrafine particles/nanoparticles in

microenvironments” O 39


Page

Gonçalves, Catarina (Universidade do Minho, Portugal)

“New dextrin nanomagnetogels: production, characterization and in vivo performance as

dual modality imaging bioprobe” O 41

Guerreiro, Joana Rafaela (iNANO, ISEP/BioMark Sensor Research & CIQ/FCUP, Denmark)

“Astringency estimation by Localized Surface Plasmon Resonance” OP 43

Gusmão, Rui (Universidade do Minho, Portugal)

“Au Nanoparticles built-in Mesoporous TiO2 Composite for Voltammetric Detection” O 45

Hagmeyer, Daniel (Microtrac Europe GmbH, Germany)

“Tool to quantify ionic activity of macromolecules and charge density on particle

interfaces” OP 47

Hwang, Jaeseok (Sungkyunkwan University, Korea)

“Synthesis of Transition Metal Dichalcogenide Atomic Layer via a Sulfurization Route” OP 48

Jaskolski, Wlodzimierz (Institute of Physics, Nicolaus Copernicus University, Poland)

“The role of octagonal defects in the electronic properties of graphene nanoribbons and

carbon nanotubes” O 49

Koppens, Frank (ICFO, Spain)

“Graphene quantum nano-optoelectronics” K 51

Kortaberria, Galder (Euskal Herriko Unibertsitatea/Basque Country University, Spain)

“Nanocomposites based on SBS triblock copolymer and selectively placed PS-grafted CdSe

nanoparticles” O 52

Kuzmenko, Igor (Ben Gurion University of Negev, Israel)

“Exotic Kondo Effect in Carbon Nanotube Quantum Dot” OP 53

Landman, Uzi (Georgia Tech, USA)

"To be defined" K -

Larkin, Ivan (Minho University, Portugal)

“Light Transmission and Reflection from a Thin Metallic Film” OP 55

Liu, Lifeng (INL, Portugal)

“Silicon Based Materials For Hybrid Solar Cells and Photoelectrochemical Cells” K 56

Llop, Jordi (CIC biomaGUNE, Spain)

“Radiolabelling of nanoparticles for nanosafety evaluation: direct beam activation” K 57

Maccaferri, Nicolò (CIC nanoGUNE Consolider, Spain)

“Plasmonic phase tuning of magneto-optics in ferromagnetic nanostructures” OP 58

Mano, João F. (3B´s Group/Minho Univ., Portugal)

“Nanostructured polymeric multilayers for biomedical applications” K 60

Marques, Paula (TEMA, Mechanical Engineering Department, Portugal)

“Graphene oxide: a multifunctional nanoplatform to build innovative materials” OP 61

Mendes, Adélio (Porto University, Portugal)

“Photoelectrochemical cells: from water splitting to electrochemical energy storage” K 63

Mergny, Jean-Louis (IECB / Inserm, France)

“Unusual Nucleic Acids for DNA-based nanodevices” K 64

Molina, Javier (Universitat Politècnica de València, Spain)

“Chemical deposition of reduced graphene oxide on fabrics” O 65

Oh, Simgeon (Sungkyunkwan University, Korea)

“Novel Synthetic Routes for Ultra-long ZnO Microwires with Cross-sectional Shape

Modulation” O 67

Pastoriza Santos, Isabel (Universidade de Vigo, Spain)

“Halides Directed growth of Au@Ag Nanoparticles” O 68

Paulo, Pedro (Instituto Superior Técnico, Centro de Química Estrutural, Portugal)

“Tip-Specific Functionalization of Gold Nanorods for Plasmonic Biosensing” O 69


Page

Petrova, Krasimira (Universidade Nova de Lisboa, Portugal)

“Synthesis of Hydrophobic Polymeric Sucrose-Containing Nanoparticles” O 71

Piedade, Ana (University of Coimbra, Portugal)

“Neural implants nanocomposite coatings with antibacterial action towards nosocomial

pathogens” O 72

Pinto, Vera (CTCP - Centro Tecnologico do Calcado de Portugal, Portugal)

“Footwear Industry: Use of nanoparticles in the development of materials with

antimicrobial properties” O 74

Pirard, Sophie (University of Liège, Belgium)

“Influence of heat exchanges and of temperature profile for carbon nanotube synthesis in

a continuous rotary reactor” OP 76

Pomposo, Jose A. (CFM, UPV/EHU, Spain)

“Single-Chain Soft Nanoparticles as Bioinspired Nanomaterials” K 78

Rana, Sohel (University of Minho, Portugal)

“Aqueous dispersion of various types of carbon nanotubes at high concentrations using

Pluronic F127” O 79

Rauls, Eva (University of Paderborn, Germany)

“Structure Formation of Organic Molecules on Salt Surfaces” OP 81

Redondo-Cubero, Andrés (Universidade de Lisboa / Insituto Superior Técnico, Portugal)

“Ion beam mixing of GaN-based quantum structures at low temperatures” O 82

Rispail, Nicolas (Instituto de Agricultura Sostenible - CSIC, Spain)

“Evaluation of semiconductor nanocrystals and superparamagnetic nanoparticles for the

development of new diagnostic and control methods of plant and human fungal

pathogen” O 84

Rosenstein, Baruch (National Chiao Tung University, Taiwan)

“Band gap opening in graphene oxides” O 86

Sadewasser, Sascha (INL, Portugal)

“Electronic and structural grain boundary properties of chalcopyrite solar cell materials” K 87

Serrano Núñez, Juan Manuel (Sesderma laboratories/ Research and development, Spain)

“Liposomes: Topical and oral bioavailability” O 88

Silva, Carla J. (CeNTI, Portugal)

“Nanomaterials – from synthesis to solutions” K 90

Sutherland, Duncan (iNANO Center Aarhus University, Denmark)

“Protein nanopatterns prepared by colloidal lithography to study cellular adhesion

complexes” O 91

Teixeira, Sara (Technische Universität Dresden/Institute for Materials Science, Germany)

“Photocatalytical degradation of antibiotics present in water” OP 93

Vasin, Andrii (Lashkaryov Institute of Semiconductor Physics, Ukraine)

“Strong and tunable white photoluminescence from carbon incorporated nanostructured

silica” O 94

Zeng, Hua Chun (National University of Singapore, Singapore)

“Development of Integrated Nanocatalysts” K 96


Index alphabetical order Keynotes

Page

Aizpurua, Javier (CFM, CSIC - UPV/EHU and DIPC, Spain)

“Optoelectronic response of quantum emitters in plasmonic nanogaps” 17

Charlier, Jean-Christophe (UCL, Belgium)

“Electronic transport in N-doped graphene and in atomic carbon chains” 30

Fortunato, Elvira (CENIMAT-I3N, Portugal)

“Thin film transistors based on metal oxide semiconductor thin films and nanoparticles” 37

Koppens , Frank (ICFO, Spain)

“Graphene quantum nano-optoelectronics” 51

Landman, Uzi (Georgia Tech, USA)

"To be defined" -

Liu, Lifeng (INL, Portugal)

“Silicon Based Materials For Hybrid Solar Cells and Photoelectrochemical Cells” 56

Llop, Jordi (CIC biomaGUNE, Spain)

“Radiolabelling of nanoparticles for nanosafety evaluation: direct beam activation” 57

Mano, João F. (3B´s Group/Minho Univ., Portugal)

“Nanostructured polymeric multilayers for biomedical applications” 60

Mendes, Adélio (Porto University, Portugal)

“Photoelectrochemical cells: from water splitting to electrochemical energy storage” 63

Mergny, Jean-Louis (IECB / Inserm, France)

“Unusual Nucleic Acids for DNA-based nanodevices” 64

Pomposo, Jose A. (CFM, UPV/EHU, Spain)

“Single-Chain Soft Nanoparticles as Bioinspired Nanomaterials” 78

Sadewasser, Sascha (INL, Portugal)

“Electronic and structural grain boundary properties of chalcopyrite solar cell materials” 87

Silva, Carla J. (CeNTI, Portugal)

“Nanomaterials – from synthesis to solutions” 90

Zeng, Hua Chun (National University of Singapore, Singapore)

“Development of Integrated Nanocatalysts” 96



Orals

(P lenary Sess ion)

Page

Alcón, Natividad (AIDO, Spain)

“The Life Cycle of Nanomaterials; Current legislation and waste management issues” 18

Alonso Gomez, Jose Lorenzo (Universidade de Vigo, Spain)

“Up-standing Chiral Architectures through Topological Self-Assembly of Enantiopure Allenes” 21

Bodelon, Gustavo (University of Vigo, Spain)

“Multifunctional Au@pNIPAM Microgels for detection of EGFR by Surface-Enhanced Resonance

Raman Spectroscopy (SERRS)” 27

Carneiro, Joaquim (University of Minho, Portugal)

“Development of a prototype based on TiO2 coated textile substrates with photocatalytic and

self- cleaning properties” 28

Cayssol, Jérôme (Bordeaux University, France)

“New topological phases in strained graphene” 29

de la Prida Pidal, Victor Manuel (Universidad de Oviedo, Spain

“Development of electrostatic nanocapacitors by atomic layer deposition on nanostructured

materials for energy storage” 32

Ferreira, Aires (National University of Singapore, Singapore)

“Extrinsic spin Hall effect in graphene” 34

Gomes, João (ISEL, Portugal)

“Notice on a methodology for monitoring ultrafine particles/nanoparticles in microenvironments” 39

Gonçalves, Catarina (Universidade do Minho, Portugal)

“New dextrin nanomagnetogels: production, characterization and in vivo performance as

dual modality imaging bioprobe” 41

Gusmão, Rui (Universidade do Minho, Portugal)

“Au Nanoparticles built-in Mesoporous TiO2 Composite for Voltammetric Detection” 45

Jaskolski, Wlodzimierz (Institute of Physics, Nicolaus Copernicus University, Poland)

“The role of octagonal defects in the electronic properties of graphene nanoribbons and

carbon nanotubes” 49

Kortaberria, Galder (Euskal Herriko Unibertsitatea/Basque Country University, Spain)

“Nanocomposites based on SBS triblock copolymer and selectively placed PS-grafted CdSe

nanoparticles” 52

Molina, Javier (Universitat Politècnica de València, Spain)

“Chemical deposition of reduced graphene oxide on fabrics” 65

Oh, Simgeon (Sungkyunkwan University, Korea)

“Novel Synthetic Routes for Ultra-long ZnO Microwires with Cross-sectional Shape Modulation” 67

Pastoriza Santos, Isabel (Universidade de Vigo, Spain)

“Halides Directed growth of Au@Ag Nanoparticles” 68

Paulo, Pedro (Instituto Superior Técnico, Centro de Química Estrutural, Portugal)

“Tip-Specific Functionalization of Gold Nanorods for Plasmonic Biosensing” 69

Petrova, Krasimira (Universidade Nova de Lisboa, Portugal)

“Synthesis of Hydrophobic Polymeric Sucrose-Containing Nanoparticles” 71


Page

Piedade, Ana (University of Coimbra, Portugal)

“Neural implants nanocomposite coatings with antibacterial action towards nosocomial

pathogens” 72

Pinto, Vera (CTCP - Centro Tecnologico do Calcado de Portugal, Portugal)

“Footwear Industry: Use of nanoparticles in the development of materials with antimicrobial

properties” 74

Rana, Sohel (University of Minho, Portugal)

“Aqueous dispersion of various types of carbon nanotubes at high concentrations using

Pluronic F127” 79

Redondo-Cubero, Andrés (Universidade de Lisboa / Insituto Superior Técnico, Portugal)

“Ion beam mixing of GaN-based quantum structures at low temperatures” 82

Rispail, Nicolas (Instituto de Agricultura Sostenible - CSIC, Spain)

“Evaluation of semiconductor nanocrystals and superparamagnetic nanoparticles for the

development of new diagnostic and control methods of plant and human fungal pathogen” 84

Rosenstein, Baruch (National Chiao Tung University, Taiwan)

“Band gap opening in graphene oxides” 86

Serrano Núñez, Juan Manuel (Sesderma laboratories/ Research and development, Spain)

“Liposomes: Topical and oral bioavailability” 88

Sutherland, Duncan (iNANO Center Aarhus University, Denmark)

“Protein nanopatterns prepared by colloidal lithography to study cellular adhesion complexes” 91

Vasin, Andrii (Lashkaryov Institute of Semiconductor Physics, Ukraine)

“Strong and tunable white photoluminescence from carbon incorporated nanostructured silica” 94



Orals

(Para l le l Sess ion)

Page

Alkan Olsson, Johanna (Centre for Environmental and Climate Research, Lund U., Sweden)

“Different perspectives on handling uncertainties in nanotechnology: Lessons from the natural

resource management area?” 19

Benavente, Juana (Universidad de Málaga, Spain)

“Influence of effective membrane fixed charge on electrolyte concentration-polarization in

nanoporous alumina membranes with similar pore size” 23

Bernardo, Cesar (Centro de Física, Portugal)

“Exciton migration in self-assembled dendrite-type fractal superstructures of monodisperse

Quantum Dots” 25

Figueiredo, António (Universidade de Aveiro, Portugal)

“Thermal Activate Concrete Slabs with Microencapsulated PCM: Mechanical and Thermal

Characterization” 35

Giannakopoulos, Angelos (Laboratory for Chemistry of Novel Materials, UMONS, Belgium)

“Workfunction Tuning of Graphene with Organic Molecules” 38

Guerreiro, Joana Rafaela (iNANO, ISEP/BioMark Sensor Research and CIQ/FCUP, Denmark

“Astringency estimation by Localized Surface Plasmon Resonance” 43

Hagmeyer, Daniel (Microtrac Europe GmbH, Germany)

“Tool to quantify ionic activity of macromolecules and charge density on particle interfaces” 47

Hwang, Jaeseok (Sungkyunkwan University, Korea)

“Synthesis of Transition Metal Dichalcogenide Atomic Layer via a Sulfurization Route” 48

Kuzmenko, Igor (Ben Gurion University of Negev, Israel)

“Exotic Kondo Effect in Carbon Nanotube Quantum Dot” 53

Larkin, Ivan (Minho University, Portugal)

“Light Transmission and Reflection from a Thin Metallic Film” 55

Maccaferri, Nicolò (CIC nanoGUNE Consolider, Spain)

“Plasmonic phase tuning of magneto-optics in ferromagnetic nanostructures” 58

Marques, Paula (TEMA, Mechanical Engineering Department, Portugal)

“Graphene oxide: a multifunctional nanoplatform to build innovative materials” 61

Pirard, Sophie (University of Liège, Belgium)

“Influence of heat exchanges and of temperature profile for carbon nanotube synthesis in a

continuous rotary reactor” 76

Rauls, Eva (University of Paderborn, Germany)

“Structure Formation of Organic Molecules on Salt Surfaces” 81

Teixeira, Sara (Technische Universität Dresden/Institute for Materials Science, Germany)

“Photocatalytical degradation of antibiotics present in water” 93

Abstracts


Javier Aizpurua1, D. Codruta

Marinica2, Rubén Esteban1 and Andrei G. Borisov2 1Materials Physics Center CSIC-UPV/EHU and DIPC, Donostia-San Sebastián, Spain 2Institut des Sciences Moléculaires d’Orsay, UMR 8214 CNRS-Université Paris-Sud, Orsay, France

[email protected]

O p t o e l e c t r o n i c r e s p o n s e o f q u a n t u m e m i t t e r s i n p l a s m o n i c n a n o g a p s

A plasmonic nanogap is an ideal platform to explore and test quantum effects in the optical response of nanoscale structures. As the separation between interfaces in a nanogap becomes below nanometric distances, the optical response of the system enters a strong nonlocal regime where the quantum nature inherent to the coherent oscillation of interacting electrons becomes apparent. We have developed full quantum mechanical calculations within time-dependent density functional theory (TDDFT) to address nonlocal effects in plasmonic gaps [1]. By doing so, we have identified a tunneling regime for separation distances of the interfaces below 0.5 nm, which totally modifies the spectral fingerprints of the cavity [2]. Quantum tunneling screens plasmonic modes localized at the cavity and establishes charge transfer across the gap producing lower energy modes of the optical response. Furthermore, we consider the presence of an emitter in the nanogap, as depicted in the figure below, under the strong coupling regime where hybrid plexcitonic modes are produced. Once the plexcitonic response obtained within classical and quantum approaches are proven to be consistent, we adopt the classical approach to incorporate resonant electron transfer (RET) into the optoelectronic response of the cavity-emitter system by including the electron transfer rates as an extra broadening into the description of the emitter. As observed in the spectra of the figure, the spectral fingerprint of the emitter is lost when it is located at short distances from the interfaces (below 1.2 nm). At very close distances from the metal interfaces, RET from the excited state of the emitter into the continuum of metallic states occurs (see scheme of states in the figure), quenching the plexcitonic fingerprint [3]. This is an effect intrinsically different to the classical quenching of emission by classical interaction with surface plasmons. The results presented here emphasize the importance of

quantum effects in the coupling between single emitters and plasmonic antennas.

References

[1] D.C.Marinica, A.K.Kazansky, P.Nordlander,

J.Aizpurua, A.G. Borisov, Nano Lett. 12 (2012) 1333.

[2] R. Esteban et al. Nature Comm. 3 (2012) 825; K. Savage et al. NATURE 491 (2012) 574.

[3] D.C. Marinica, H. Lourenço-Martins, J. Aizpurua, A.G. Borisov, Nano Lett. ASAP (2013) Nov. 8.

Figures

Figure 1: Top left: Scheme of a quantum emitter located at the gap of a plasmonic dimer with separation distance S. Bottom left: Process of resonant electron transfer (RET) depicted as a red arrow between the excited (e) state of the emitter and the continuum of states of the metal, related to the Fermi Energy Ef. Light of energy hν drives the emitter from the ground state (g) to the excited. Right: Absorption spectra of the coupled emitter-gap system for different separations of the gap (0.9nm-2nm). For small separation distances, the emitter’s fingerprint is quenched.


Natividad Alcón1, Niina Nieminen2,

Satu Ikonen2, Hanna-Kaisa Koponen2 1AIDO, Spain 2Technology Centre KETEK Ltd, Finland

T h e L i f e C y c l e o f N a n o m a t e r i a l s ; C u r r e n t

l e g i s l a t i o n a n d w a s t e m a n a g e m e n t i s s u e s

The exponential growth in the use of engineered nanomaterials in consumer products has raised discussion about their health and environmental safety. The data gained from the studies so far is diverse and dispersed which makes it hard to make a proper evaluation of nanomaterials’ environmental effects. Because of the lack of nano specific legislation the mandatory obligations are hard to find and obey. The manufacturers of nanomaterials face these problems every day. One still somewhat neglected issue is the problem of the waste containing nanomaterials, nanowaste. At the moment there are no instructions or legislation on handling nanowaste and no monitoring system to follow the nanoparticles containing products during and in the end of their life cycle. Thus, most of these materials sooner or later end up in normal waste handling processes. The shortage of data on quantities and qualities of nanowaste as well as the lack of classification system for it makes the management of nanowaste challenging. The current awareness and approaches on handling nanomaterials by the Finnish, Portuguese, Spanish and Romanian companies working with nanomaterials have been charted and the results imply that there is demand for more open discussion on the topic.

Current EU legislation has only few nanospesific directives. The ongoing debate is that is more nano-lex needed or would it be enough to update the current legislation to cover nanomaterials and –technologies? The legislation is developing fast and around the Europe a lot of effort is put on developing sufficient analysis methods for measuring the environmental impacts of different nanomaterials. For companies working with nanomaterials a database covering the current legislation and possible analysis/characterization methods would be beneficial for them to stay up to date with what is going on on the legislative sector as well as for minimizing the environmental impacts of their activities.


Johanna Alkan Olsson1 & Ilhami

Alkan Olsson2 1Centre for Environmental and Climate Research The Ecology building, Sweden 2Istanbul University Faculty of Political Science Istanbul Üniversitesi Merkez Kampüsü 34452 Beyazıt/Fatih-İstanbul

[email protected]

D i f f e r e n t p e r s p e c t i v e s o n h a n d l i n g u n c e r t a i n t i e s i n

n a n o t e c h n o l o g y : L e s s o n s f r o m t h e n a t u r a l r e s o u r c e

m a n a g e m e n t a r e a ?

With the current levels of complexity and risk that certain areas of science and technology have reached, in particular in nanoscience and biotechnology, the perspectives of the concept of uncertainty have gained new dimensions alongside with a requirement for a redefinition of the concepts, such as ‘precaution’ and ‘collaborative decision making’ that may suit better to this new situation, which requires an adaptive law approach, or an “ongoing normative assessment” as put by Dupuy and Grinbaum while pointing out the shortcomings of the precautionary principle.

These concerns are increasingly encountered in the public policy sphere as conflicts between community and interest groups proliferate, and the environmental, health, and social aspects of nanotechnology become more prominent. The realisation that there is a need to consider a wide variety of values, knowledge, and perspectives in a collaborative decision making process has led to a multitude of new methods and processes being proposed to govern the use and development of nanotechnology.

This paper aims to revisit collaborative decision making models, including participatory forms of uncertainty and risk assessment from the area of natural resource management and planning with a view to transpose them into the nanotechnology context. The focus will be on the following two questions: (i) what might be the benefits of using participatory approaches to uncertainty and risk assessment in the field of nanotechnology? and, (ii) how could exactly these approaches be incorporated in complex legal-institutional settings to realise these potential benefits?

The first section gives an overview of the collaborative decision making models with regard

to uncertainty and risk assessment in the area of natural resource management and planning. The following part examines the proposed collaborative decision making models concerning uncertainty and risk assessment in the nanotechnology area. Part three will compare and discuss the models used in the two areas and suggest what approaches(s) can be more adaptive to handle the complexity of uncertainty and risk in the area of nanotechnology.

The paper is based on literature reviews of collaborative decision making models for uncertainty and risk assessment from natural resource management and planning and the Nanotechnology areas. These models are thereafter compared by assessing the benefits and downsides of different models in relation to handle complexity.

References

[1] Barbara Koremenos (2005) “Contracting

around International Uncertainty”, American Political Science Review, 99 (4)

[2] D.M. Bowman & G.A. Hodge (2007) “A small matter of regulation: an international review of nanotechnology regulations”, Columbia Science & Technology Law Review, 8

[3] Jean-Pierre Dupuy and Alexei Grinbaum (2005), “Living with Uncertainty: Toward the Ongoing Normative Assessment of Nanotechnology”, Techné: Research in Philosophy and Technology, 8 (2)

[4] Linda K. Breggin and Leslie Carothers (2006) “Governing uncertainty: the nanotechnology environmental, health, and safety challenge”, Columbia Journal of Environmental Law, 31


[5] Nanoscience and nanotechnologies: opportunities and uncertainties, The Royal Society & The Royal Academy of Engineering Report (April 2004)

[6] Robert Falkner and Nico Jaspers (2012) “Regulating Nanotechnologies: Risk, Uncertainty and the Global Governance Gap”, Global Environmental Politics, 12(1)

[7] J. Weckert, J. & J. Moor, (2006) ”The precautionary principle in nanotechnology”, International Journal of Applied Philosophy, 20


José Lorenzo Alonso-Gómez, Yi-Qi Zhang, Murat Anil Öner, Inmaculada R. Lahoz, Borja Cirera, Carlos-Andres Palma,* Silvia Castro-Fernández, Sandra Míguez-Lago, M. Magdalena Cid, Johannes V. Barth, Florian Klappenberger Departamento de Quimica Orgánica, Universidade de Vigo, 36310 Vigo, Spain

[email protected]

U p - s t a n d i n g C h i r a l A r c h i t e c t u r e s t h r o u g h

T o p o l o g i c a l S e l f - A s s e m b l y o f E n a n t i o p u r e A l l e n e s

Materials capable or rotating light are of great interest in optics and photonic logics. We have at hand chiral systems presenting among the strongest chiroptical responses within organic molecules [1]. Those responses are very sensitive to conformational changes. Herein we present the first study of chiral allenes on STM. These enantiomerically pure molecules present a very densely packed topological selfassembly on Ag(111). The flexibility and chirality of (P,P)-1 (Figure 1), enable the topological self-assembly on a Ag[1,1,1] as ascertain by the combination of experimental ultra-high vacuum scanning tunneling microscopy (UHVSTM) and molecular dynamics (Figure 2) [2]. We achieved the construction of up-standing complex chiral architectures from enantipure allenes. Topological self-assembly was found to have a crucial role in the formation of these novel chiral surfaces as ascertained by a combination of computational modeling, mass spectrometry and molecular manipulation studies. Careful analysis of high-resolution STM images confirm the transfer of chirality from single molecules to 2D networks. The use of enantiopure allenes with strong chiroptical responses along with their up-standing organization opens great possibilities for the construction of new smart materials that could be implemented into devises like sensors, catalysts, or logic gates. We expect to obtain chiral amplification due to the ordering of the chiral molecules as well as to control of the chiroptical responses by a tunable applied electric filed.

References

[1] I. R. Lahoz, A. Navarro-Vázquez, A. L. Llamas-

Saiz, J. L. Alonso-Gómez, M. M. Cid Chem. Eur. J. 2012, 18, 13836-13843.

[2] Y. Q. Zhang, S. Castro-Fernández, S. Míguez-Lago, I. R. Lahoz, A. Navarro-Vázquez, B. Cirera, M. A. Öner, C-A Palma, F. Klappenberger, J. L. Alonso-Gómez, M. Cid, J. Barth, in preparation.


Figures

Figure 1: (a) Synthesis of (M,M)-1 (Tol: Toluene) - N,N,N´,N´-

Tetramethylethylenediamine (TMEDA). (b) Left: Three different conformations (blue, green, red) of (M,M)-1 by rotation about

and

. Right: View of the allene unit along the axis of rotation.

Figure 2: (a) Model of the molecular network unit-cells with proposed registry. Inset shows STM image in the same scale (Ub = −0.5 V, It = 0.1 nA). The unit-cell vectors aL and bL enclose the angle α. The angles θ, θ’ are defined between the [11–2] direction and vector aL and aR, respectively. The primitive vectors of the Ag(111) surface are u and v. All six domains are experimentally observed (see Figure S3). High-resolution STM images of diastereomeric domains: (b) MM-L (Ub = −0.3 V, It = 0.1 nA) and (c) MM-R (Ub = −0.35 V, It = 0.05 nA). Dashed circles are contours of each single-molecule feature. Scale bars denote 10 Å. (d) Comparison of the outlines of MM-L and MM-R units. (e) The profiles of MM-L and MM-R domains are compared.


J. Benavente1, V. Romero1,

S. Cañete2, V. Vega3, J. García3, V.M. Prida3 and B. Hernando3 1Grupo de Caracterización Electrocinética en Membranas e Interfases. Universidad de Málaga, Spain 2Unidad de Radioisótopos, Universidad de Málaga, Spain 3Departamento de Física. Facultad de Ciencias. Universidad de Oviedo, Spain.

[email protected]

I n f l u e n c e o f e f f e c t i v e m e m b r a n e f i x e d c h a r g e o n e l e c t r o l y t e c o n c e n t r a t i o n -

p o l a r i z a t i o n i n n a n o p o r o u s a l u m i n a m e m b r a n e s w i t h

s i m i l a r p o r e s i z e

Solid structures with accurate nanopore diameters and narrow pore size distributions are necessary for the study of confined diffusion, since they facilitate the control and modeling of molecular transport which is of great interest in different applications [1]. Particularly, Nanoporous Alumina Membranes (NPAMs) fabricated via electrochemical anodization, which present a well-defined pore structure with rather high density of uniform nanopores while their dimensions and porosity can easily be controlled by the anodization process [2], are used in nanofluidics, solution purifications and drug delivery devices [3]. These applications are associated with motions of molecules or ions inside the membrane nanopores, which are usually investigated by performing diffusion experiments at a given concentration gradient using Fick law, independently of the neutral or charged character of the solutes or the higher or lower fixed charge of the membranes [4-5]. On the other hand, solution stirring is not usually considered in many of the experimental systems used in drug delivery characterization devices [5-6], which can favour the solute accumulation on the membrane surface or concentration-polarization effect schematically shown in Fig. 1(a) and to mask the effective concentration gradient. However, these factors could be among the reasons associated to the significant reduction in diffusion coefficients across NPAMs with pore size between 20 and 40 nm reported by different authors when diffusive transport of charged species (macromolecules and ions) is analyzed [5-7]. In this study, the influence of membrane equivalent fixed charge on concentration-polarization at the solution/membrane interface is considered.

Diffusive transport across two nanoporous alumina membranes (NPAMs) fabricated by the two-step anodization process [2] with similar pore size (~ 20 nm) and thickness (~ 60 μm) was determined. One of the studied membranes is commercial (Anopore®) and it has a porosity between 25-50 % (indicated by supplier), while the other is experimental (AL1) and with a porosity of 16-20 % [4]. This latter membrane was fabricated using a constant anodization potential of 25 V applied between the Al foil and a Pt counter-electrode in a 0.3 M sulfuric acid solution. Membranes behaviour was analyzed by measuring membrane potentials at different NaCl solution concentrations ratio (Cf/Cv ranging between 0.2 and 10) and hydrodynamic conditions (solutions stirring rate of 0 rpm and 540 rpm).

Differences in the electrical behaviour of both membranes can be determined by comparing membrane potential values obtained for both membranes at the same solutions concentration ratio and hydrodynamic condition. The analysis of these data by using the TMS model [8-9] allows us the estimation of both the effective membrane fixed charge (Xef) and cation transport number (t+) and their values are indicated in Table 1. These results clearly show the almost neutral character of the Anopore membrane (t+ ~ solution cation transport number t+

o = 0.38) and the more electropositive character of the AL1 membrane when compared with the Anopore one. This fact affects both ion transport and interfacial effects as it is schematically represented in Fig. 1(b).


membrane Xef (M) t+

Anopore 1.0x10-3 0.35

AL1 10.0x10-3 0.25

Table 1: Effective fixed charge concentration, Xef, and cation transport number, t+, for both studied membranes

The comparison of membrane potential values obtained for the practically neutral Anopore membrane at the same solutions concentration ratio but different hydrodynamic conditions does not show almost differences, while solution stirring significantly affects membrane potential values in the case of the charged AL1 membrane, which is an indication of the contribution of concentration-polarization in the values obtained with this membrane (see Fig. 1(b)).

This effect might also be affected by slight surface differences between both membranes related with the fabrication process as well as by the lower porosity of the AL1 membrane, which should also be taken into account. Particularly, the effect of membrane porosity has separately been considered by comparing results obtained from diffusion measurements, which were performed with a neutral solute (tritiated water radiotracer) to avoid any electrical contribution able to mask pure diffusion data. Moreover, due to the similar pore size of both membranes comparable frictional/steric effects can be assumed.

Acknowledgments: To MINECO, Spain, for financial support (projects CTQ2011-27770, MAT2010-20798-C05-04, FEDER funds). V. Romero thanks to CICYT (FPU grant) and J. Garcia to FICyT (Severo Ochoa grant).

References

[1] Adiga, S. P.; Jin, Ch.; Curtis, L. A.; Monteiro-

Riviere, N. A.; Narayan, R. J., WIREs Nanomedicine and Nanobiotechnology Advances Reviews, 1 (2009) 568-581.

[2] Masuda, H.; Fukuda, K., Science,268 (2005)1466-1468.

[3] Karnik, R.; Fan, R.; Yue, M.; Li, D.; Yang, P.; Majumdar, A., Nano Lett., 5 (2005) 943-948.

[4] Romero, V.; Vega, V.; García, J.; Zierold, R.; Nielsch, K.; Prida, V. M.; Hernando, B.; Benavente, J., ACS Appl. Mater. & Interfaces, 5 (2013) 3556-3564.

[5] Bluhm, E. A.; Bauer, E.; Chamberlin, R. M.; Abney, K. D.; Young, J. S.; Jarvinen, G. D., Langmuir, 15 (1999) 8668-8672.

[6] Leoni, L.; Boiarski, A.; Desai, T. A., Biomedical Microdevices, 4 (2002) 131-139.

[7] Kennard, R.; DeSisto, W. J.; Mason, M. D., Appl. Phys. Lett., 97 (2010) 213701.

[8] Meyer, K. H.; Sievers, J. F., Helv. Chim. Acta, 19 (1936) 646-651.

[9] Teorell, T., Discuss. Faraday Soc., 21 (1956) 9-26.

Figures

Figure 1: Schematic representation of: (a) concentration-polarization at the membrane/solution interface; (b) effect of membrane charge on ion transport and interfacial effects.


César Bernardo1, M. Belsley1, Paulo

Coutinho1, Peter Schellenberg1, Isabel Moura1, Yuriel Núñez Fernández1,2, Tobias Stauber3, Mikhail Vasilevskiy1 1Centro de Física, Campus de Gualtar, Universidade do Minho, 4710-057 Braga, Portugal 2Departamento de Física Teórica, Universidad de La Habana, Vedado, La Habana, Cuba 3Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Madrid, Spain

[email protected]

E x c i t o n m i g r a t i o n i n s e l f -a s s e m b l e d d e n d r i t e - t y p e

f r a c t a l s u p e r s t r u c t u r e s o f m o n o d i s p e r s e Q u a n t u m D o t s

Quantum dots (QDs) are promising photoluminescent nanoparticles for a vast range of applications, from fundamental tools for light reception, building blocks for nano-photonic devices and sensitizers for solar panels to biomarker and bio-imaging applications. They are extremely stable against photobleaching, are bright and are easily tunable in color throughout the optical spectrum, while their other physical and chemical properties are not influenced. [1]

QDs can aggregate to self-assembled polycrystalline structures such as nanowires or dendrite-like two-dimensional (2D) or three-dimensional (3D) superstructures with dimensions in the micrometer range. [2]

Due to the dense packing of QDs, Förster resonance energy transfer (FRET) may compete with deexcitation, and the specific dendrite shaped structure suggests the possibility of funneling of excitation from the edges of the structure to the center. To explore this idea, we investigated dendrite shaped superstructures made of two different QDs, namely CdSe/ZnS and CdTe. These two QDs are mostly distinguished by their fluorescence quantum yield (QY), which is much higher in CdTe compared to CdSe, and this scales with the QY resp. the Förster radius for near-field energy transfer.

To compare the energy transfer properties in these two systems we employed spectral and lifetime mapping of the fluorescence to investigate energy transfer efficiency.

The experiments showed, that the spatial variation of the fluorescence lifetime was very different in the two systems. In dendrite shaped superstructures prepared from CdTe, the fluorescence decay was significantly faster in the edges compared to the center (fig.1.Left). In contrast, it was slightly slower in the edges compared to the center in CdSe/ZnS (fig.1.Right) based structures. A theoretical model using master equations for exciton occupation and migration probabilities was been used to reproduce the experimental findings. Using a large and a small Förster radius in these simulations lead to lifetime maps corresponding to the experimental results (fig.2). [3]

The observed effects may lead to devices with improved energy collection efficiency by using QDs fractal superstructures, for example in solar collector usage.

References

[1] A. L. Rogach (ed.), Semiconductor Nanocrystal Quantum Dots; Springer-Verlag: Wien, 2008.

[2] A. Sukhanova, A. V. Baranov, T. S. Perova, J. H. M. Cohen, and I. Nabiev, Controlled Self-Assembly of Nanocrystals into Polycrystalline Fluorescent Dendrites with Energy-Transfer Properties, Angew. Chem. Int. Ed. 2006, 45, 2048-2052.

[3] César Bernardo, Isabel Moura, Eduardo Pereira, Yuriel Fernández, Paulo Coutinho, Peter Schellenberg, Michael Belsley, Manuel Costa, Tobias Stauber, Arlindo Garcia and Mikhail Vasilevskiy "Energy transfer via exciton transport in quantum dot based self-assembled fractal superstructures J. Phys. Chem. C, submitted.


Figures

Figure 1: (Top): Average lifetime (first moment of decay kinetics) for a CdTe (Left) and CdSe/ZnS (Right) QDs dendrite-type fractal superstructure. The lifetime is color coded according to the scale in nanoseconds. (Bottom): Calculated lifetime map for generated diffusion-limited aggregation fractal clusters of mono-size QDs, for values of a long (Left) and small-range(Right) interaction. The color scaling evolves from low to high values (Bright to dark).


G. Bodelon, V. Montes-Garcia, C. Fernandez-Lopez, I. Pastoriza-Santos, L.M. Liz-Marzan, J. Perez-Juste

University of Vigo, Dept. of Physical Chemistry, 36310 Vigo, Spain

[email protected]

M u l t i f u n c t i o n a l A u @ p N I P A M M i c r o g e l s f o r d e t e c t i o n o f E G F R b y S u r f a c e - E n h a n c e d

R e s o n a n c e R a m a n S p e c t r o s c o p y ( S E R R S )

A surface-enhanced resonance Raman spectroscopy (SERRS) method has been developed for the detection of cells expressing the Epithelial Growth Factor Receptor (EGFR), a biomarker that is overexpressed in cancer. The SERRS active microgels were prepared by conjugating polyisopropylamide (pNIPAM) coated gold nanoparticles with receptor-specific antibodies and dye molecules. The microgels were prepared by coating gold nanoparticles with a porous thermoresponsive polymer shell (pNIPAM), which allows the diffusion of the dye molecules, followed by coating with polyacrylic acid through layer-by-layer technique. The functionalization of the microgels with specific antibodies against EGFR by carbodiimide chemistry, allowed specific binding to EGFR-expressing cells grown in vitro. The presence of EGFR was determined by Raman spectroscopy. Our results demonstrate that the multifunctional Au@pNIPAM microgels can be used as substrates for sensitive detection of EGFR by SERRS and for the generation of new multiplexing platforms.

Figures


Joaquim Carneiro1, S. Azevedo1, C.

Silva1, T.M. Barbosa1, F. Fernandes1, J. Neves2, V. Teixeira1 1Department of Physics, University of Minho, Portugal 2Textile Engineering Department, University of Minho, Portugal

[email protected]

D e v e l o p m e n t o f a p r o t o t y p e b a s e d o n T i O 2 c o a t e d t e x t i l e

s u b s t r a t e s w i t h p h o t o c a t a l y t i c a n d s e l f c l e a n i n g p r o p e r t i e s

The adhesion to the European Commission and the creation of an internal market with free circulation of goods, people, services and capitals have put a challenge in the adaptability of the transforming industry. The industrial context have changed with the intensity of the globalization process which was based on a logic of vertical disintegration, either by increasing the interdependence between manufacturing and services in the reorganization of companies’ productive processes, either by their geographical relocation and formation of international value chains. The textile and clothing Industry, typically defined as “traditional” is a significant part of the manufacturing industry in Europe and also ensures a considerable amount of jobs. By another hand, the number of small and medium enterprises (SMEs) that cluster in specific regions reinforces its importance in social, economic and cultural terms. Although there have been considerable changes in the recent years, there is widespread recognition that the production based on traditional textile products will not be enough to empower this business area. In this sense, the textile and clothing and become competitive.

Nanocoatings applied in textile finishing are a very attractive way to add value to day-to-day products offering an interesting set of important and differentiated properties. The photocatalytic activity of titanium dioxide (TiO2) based nanomaterials for textile applications has been identified as a strategic vector with great industrial impact. The development of photocatalytic, self-cleaning and antimicrobial surface finishes in common textiles has the potential to be used as a prophylactic measure to reduce the infection rates in hospitals as well as reduce the environmental impact of washing processes.

The main goal of this research work was the production of TiO2-based finished textile substrates without changing its surface characteristics such as aesthetic and sensorial (e.g. touch feeling) properties. The applied textile finishing technique in this research work needs less to none of the solvents or surfactants commonly used in the industry leading to a cleaner production process reducing significantly the environment pollution. Pulsed DC Magnetron Sputtering technique was used to deposit TiO2 thin films onto glass and Poly(lactic acid) (PLA) and cotton based substrates (10x10 cm). The samples were characterized via Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), Atomic Force Microscopy (AFM), Contact Angle measurements and UV – visible Spectroscopy techniques. The photocatalytic activity of the samples was studied by measuring the Methylene Blue (MB) degradation over time as a result of the catalyst exposure to ultraviolet (UV) radiation and its correlation with the initial concentration. The produced ultrathin films (with a thickness of 130 nm) presented a photocatalytic efficiency of about 30%. Acknowledgment: The author would like to acknowledge NanoValor Project – “Creation and Promotion of a Competitiveness Pole in Nanotechnology for the capitalization of R&D potential in the North of Portugal-Galicia Euro-region” (reference: 0585_NANOVALOR_1_P) co-funded by ERDF through the Operational Programme for Cross-border Cooperation Spain-Portugal 2007-2013 (POCTEP) www.nanovalor.org


Jérôme Cayssol1, P. Ghaemi2, D. N.

Sheng3 and A. Vishwanath4 1Bordeaux and CNRS, LOMA, France 2Department of Physics, University of Illinois, USA 3Department of Physics and Astronomy, California State University, USA 4Department of Physics, University of California-Berkeley, USA

[email protected]

N e w t o p o l o g i c a l p h a s e s i n s t r a i n e d g r a p h e n e

I will first introduce Dirac systems and topological insulators using graphene as a guideline. Then I will talk about our results on topological phases arising in strained graphene in the absence of magnetic field [1]. The strain generates nearly uniform pseudo magnetic fields which are opposite for the two valleys of graphene. The non-interacting part of our model describes the zero magnetic field pseudo Landau level (PLL) structure recently proposed [2] and experimentally reported [3] in strained graphene. Since the reported effective magnetic fields [2] range from 60 T up to 300 T, the interaction-driven phases might conceivably be realized with larger energy gaps than in Fractional Quantum Hall states under a real magnetic field. Besides strained graphene, our results also pertain for artificial graphenes such as molecular graphene [4] or cold atoms loaded in optical lattices [5].

More specifically, we have investigated the zero energy PLL at 2/3 filling [3]. In presence of the unscreened Coulomb interaction, electrons realize a 2/3 Hall state breaking time-reversal symmetry. Upon tuning the local part of the interaction, this 2/3 state can be destabilized towards a time-reversal symmetric state realizing a 1/3 Laughlin state in each valley. This state has a 9-fold ground state degeneracy and can be seen as a valley fractional topological insulator (FTI). For local attractive interactions, the 1/3+1/3 FTI has a transition towards a superconducting state. On raising the filling to the neutrality point, namely for the halffilled zero energy PLL, we find either a ferromagnet or a valley polarized state depending on the strength of the on-site interactions.

References

[1] P. Ghaemi, J. Cayssol, D. N. Sheng and A.

Vishwanath, Fractional topological phases and broken time reversal symmetry in strained graphene, Phys. Rev. Lett. 108, 266801 (2012).

[2] F. Guinea, M.I. Katsnelson, and A.K. Geim, Energy gaps and a zero-field quantum Hall effect in graphene by strain engineering, Nat. Phys. 6, 30 (2010).

[3] L. Levy et al., Strain-induced pseudomagnetic fields greater than 300 tesla in graphene nanobubbles, Science 329, 544 (2010).

[4] K. K. Gomes, W. Mar, W. Ko, W. Guinea, and H. C. Manoharan, Nature (London) 483, 306 (2012).

[5] L. Tarruell, D. Greif, T. Uehlinger, G. Jotzu, and T. Esslinger, Nature (London) 483, 302 (2012).


Jean-Christophe Charlier

University of Louvain, Institute of Condensed Matter and Nanosciences, Louvain-la-Neuve, Belgium

[email protected]

E l e c t r o n i c t r a n s p o r t i n N - d o p e d g r a p h e n e a n d i n

a t o m i c c a r b o n c h a i n s

The incorporation of foreign atoms into the carbon honeycomb network lattice has been widely investigated in order to modify the electronic and chemical properties of graphene [1-3]. In contrast with conventional materials, the effect of foreign atoms in a 2D material, such as graphene, is expected to depend significantly on the position and the local environment of each atom due to the quantum confinement of the electrons. Recent scanning tunneling microscopy and spectroscopy studies of N-doped graphene have revealed how the incorporation of this foreign atom into the sp2 lattice occurs. The exposure of graphene to a nitrogen plasma flux after synthesis leads to an homogeneous distribution of substitutional atoms [2]. However, when a nitrogen source is introduced during the CVD growth of graphene, the nitrogen incorporation exhibits a preferential accommodation within one of the two triangular sublattice that compose the honeycomb network [1,3]. Ab initio STM images and computed local density of states reveal specific signatures for each type of nitrogen defects, which are then correlated with experimental STM/STS measurements, thus confirming the different possible atomic configurations of N-doping in graphene [3]. Although such unbalanced sublattice nitrogen doping in graphene is not hitherto understood, the consequences of this peculiar atomic arrangement on the electronic and transport properties of graphene are addressed in this work.

Electronic structure and transport properties of N-doped graphene with a single sublattice preference are investigated using both first-principles techniques and areal-space Kubo-Greenwood

approach [4]. Such a breaking of thesublattice symmetry leads to the appearance of a true band

gapin graphene electronic spectrum even for a

randomdistribution of the N dopants. In addition, a natural spatial separation of both types of charge carriers at the band edge is observed, leading to a

highly asymmetric electronic transport. For such N-doped graphene systems, the carrier at the conduction band edge present outstanding transport properties including long mean free paths, high mobilities and conductivities. Such a transport behavior can be explained by a non-diffusive regime (quasi-ballistic transport behavior at the conduction band edge), and originates from a low scattering rate. The presence of a true band gap along with the persistence of carriers traveling in an unperturbed sublattice suggest the use of such N-doped graphene in G-FET applications, where a high ION/IOFF ratio is expected. The present ab initio simulations should encourage more investigation and specific transport measurements on N-doped graphene samples where such an unbalanced sublattice doping is observed.


As strings of monoatomic thickness, chains of sp-hybridized carbon atoms constitute the logical one-dimensional phase of carbon. These 1D systems have been proposed theoretically for a long time until they were observed in electron microscopy studies. However, electrical measurements on these monoatomic chains have not been feasible. Now, by using a measuring system with an STM tip in a TEM specimen stage, carbon chains are not only produced but their electrical properties are also measured. Ab initio simulations (confirmed by MBPT calculations) reveal that strain has a decisive influence on the bandgap of the chain, thus determining its conductivity [5].

References

[1] Visualizing individual nitrogen dopants in

monolayer graphene L. Zhao, et al., Science 333, 999 (2011).

[2] Localized state and charge transfer in nitrogen-doped graphene F. Joucken, et al., Phys. Rev. B 85, 161408(R) (2012).

[3] Nitrogen-doped graphene : beyond single substitution and enhanced molecular sensing R. Lv, Q. Li, A.R. Botello-Mendez, et al. Nature - Scientific Reports 2, 586 (2012).

[4] [Electronic and transport properties of unbalanced sublattice N-doping in graphene A. Lherbier, A.R. Botello-Méndez, and J.-C. Charlier, Nano Lett. 13, 1446-1450 (2013).

[5] Electrical transport measured in atomic carbon chains O. Cretu, A. R. Botello-Mendez, I. Janowska, C. Pham-Huu, J.-C. Charlier, and F. Banhart Nano Lett. 13, 3487-3493 (2013).


L. Iglesias, V. Vega, J. García, B. Hernando and V.M. Prida Depto. Física, Univ. de Oviedo, Oviedo (Spain)

[email protected]

D e v e l o p m e n t o f e l e c t r o s t a t i c n a n o c a p a c i t o r s b y a t o m i c

l a y e r d e p o s i t i o n o n n a n o s t r u c t u r e d m a t e r i a l s f o r

e n e r g y s t o r a g e

The outstanding features of nanostructured materials are the key for the next generation of energy harvesting and storage devices. The requirements pursued for the energy storage devices are given in terms of energy stored (W·h.) and maximum power supplied (W). For many applications in which significant energy is needed in pulse form, conventional electrolytic capacitors cannot provide enough power. Instead of that, the development of high energy density capacitors combined with high power supply plays an important role. In this way, one of the most promising applications of nanomaterials for energy storage technologies consists in making progress on Electrostatic Nanocapacitors (ENCs) by taking advantage of the high surface area of nanostructured substrates and novel thin film deposition techniques to achieve high capacitance values [1,2]. When aiming to obtain extremely high capacitance densities, it becomes necessary to combine an increased effective surface area with a high dielectric constant and reduced thickness of dielectric material.

Nanoporous Anodic Alumina Membranes (NAAM) are excellent high free surface-area substrates due to their self-ordered porous structure with well defined lattice parameters and high aspect ratio values that can be adjusted by controlling the anodization conditions. However, the increased surface area requires the ability to deposit thin films with conformal coverage and uniform layer thickness on the walls of a high aspect ratio porous structure. The Atomic Layer Deposition (ALD) technique is among the outstanding methods that can provide a precise manner to control the film thickness deposition at the atomic scale. Therefore, the combination of NAAM templates together with ALD technique allows for the conformal deposition of metal oxide films replicating the 3D morphology of the nanoporous substrate while keeping a high thickness control.

In this work, we report on the fabrication of ENCs by ALD conformal deposition of a conductor-dielectric-conductor (CDC) structure on the surface of NAAM, with pore diameter (Dp) about 65nm and pore length (L) around 10µm. The ENC structure was constituted, as can be seen in the diagram of Figure 1, by alternating layers of Aluminium-doped Zinc Oxide (AZO), as Bottom Electrode (BE) and Top Electrode (TE), with respective thicknesses of 12 and 24nm, together with an intermediate alumina (Al2O3) dielectric layer having a dielectric constant between 7-9 and 10nm in thickness. The deposition rate of the Al2O3 and AZO coating layers have been studied by ellipsometry, while the conformality of CDC structure was confirmed by Transmission Electron Microscopy (TEM) (Figure 1) and Scanning Electron Microscopy (SEM) techniques. Likewise, the crystalline structure of the deposited thin films was determined by TEM and X-Ray Diffraction (XRD).

The electrical characterization of different ENCs prototypes was performed in the frequency range of 40 Hz up to 100 MHz by using a LCR impedance analyzer. It is found that the capacitance decreases strongly with the frequency, but at the low frequency of 40 Hz it reaches about 200µF/cm2 (Figure 2 b)). This result is well correlated with the theoretically calculated capacitance according with the geometric structure of the ENCs surface area. Additionally, the frequency dependence of the impedance module and phase, shown in the Figure 2 a), indicates that ENCs follow frequency behaviour similar to commercial capacitors but enhanced capacitance areal density. Reference

[1] P. Banarjee et al, Nat. Nanotechnol., 4, (2009),

pp. 292. [2] L.C. Haspert, S.B. Lee, G.W. Rubloff, ACS Nano,

6, (2012), pp. 3528.


Figures

Figure 1: Schematic picture of a NAAM with the AZO-Al2O3-AZO trilayer constituting the ENC device. The magnification on the right displays a TEM image of the sample cross section showing the CDC structure deposited by ALD technique

Figure 2: LCR impedance measurements: a) impedance module and phase behavior with the frequency, b) resistance and capacitance dependence on the frequency of the ENCs devices.

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Aires Ferreira1, T. G. Rappoport2, M.

A. Cazalilla1 and A. H. Castro Neto1,3 1Graphene Research Centre and Department of Physics, National University of Singapore, Singapore 2Instituto de Física, Universidade Federal do Rio de Janeiro, Brazil 3Department of Physics, Boston University, USA

[email protected]

E x t r i n s i c s p i n H a l l e f f e c t i n g r a p h e n e

We show that extrinsic spin Hall effect can be engineered in monolayer graphene by decoration with small doses of adatoms, molecules or nano-particles originating local spinorbit perturbations [1]. The analysis of the single impurity scattering problem shows that intrinsic and Rashba spin-orbit local couplings enhance the spin Hall effect via skew scattering of charge carriers in the resonant regime. The solution of the transport equations for a random ensemble of spin-orbit impurities discloses that giant spin Hall currents are within the reach of current state-of-the-art in device fabrication. The extrinsic spin Hall effect is found to be robust with respect to thermal fluctuations and disorder averaging. Our findings suggest that functionalized graphene systems can be used to design spintronic integrated circuits with SHE-based spin-polarized current activation and control.

References

[1] A. Ferreira, T. G. Rappoport, M. A. Cazalilla, and

A. H. Castro Neto, pre-print: http://arxiv.org/abs/ 1304.7511


A. Figueiredo, R. Vicente, J. Lapa; F. Rodrigues, C. Cardoso, T. Silva Civil Engineering Department University of Aveiro, 3810-193 Aveiro, Portugal

[email protected]

T h e r m a l A c t i v a t e C o n c r e t e S l a b s w i t h M i c r o e n c a p s u l a t e d P C M : M e c h a n i c a l a n d T h e r m a l

C h a r a c t e r i z a t i o n

In the framework of an energy storage research project, an experimental campaign on concrete with incorporation of microencapsulated phase change material (PCM) was carried out. The main objective was to study various issues related to the behaviour, including the mixing and incorporation process, with particular emphasis on mechanical and thermal properties. Despite the thermal characteristics provided from the PCM incorporation into the concrete mixture, the mechanical properties are affected. Therefore, an experimental campaign was carried out to evaluate the compression and bending strength of concrete with PCM. The PCM concrete mixture analysed is composed by 3.21% of PCM in weight proportional to all aggregates, binders and other additives.

Following the NP EN 12390-3 [1] and NP EN 12390-5 [2], the concrete with PCM incorporation was characterized in terms of compression and bending strength at ambient and higher temperatures (simulating a thermal activated concrete screed slabs). Eighteen cubic specimens with 15x15x15cm3 dimensions according to NP EN 12390-1 [3], twelve cylindrical specimens with a diameter of 15cm and height with twice the value of diameter and sixteen parallelepiped test specimens were produced.

Thermal tests to evaluate the behaviour of concrete with PCM in terms of energy storage capacity were performed. The test specimens were placed in a climatic chamber, heated up to 45°C to simulate thermal activation. When this temperature was reached the chamber was opened and cooled down until samples attained stable ambient temperature.

Experimented results revealed that PCM incorporated into concrete led to a reduction of the maximum compression strength of about 66% and a reduction of 52% of maximum bending strength (see Figure 1),in comparison with the reference concrete (specimens without PCM). These results are in

accordance with others experiences caused out by other authors [4,5,6]. The same tests were repeated on other samples under the effect of temperature, in order to verify the effect caused by the phase change process of the microencapsulated PCMs.

In respect to the thermal performance of concrete incorporating PCM (see Figure 2) it was found that the use of this mix for a concrete slab screed layer, potentially contributes to reduce the energy consumed in buildings resourcing to active heating systems.

References

[1] NP EN 12390-3, Testing hardened concrete. Part

3: Compressive strength of test specimens, 2011).

[2] NP EN 12390-5, Testing hardened concrete. Part 5: Flexural strength of test specimens, (2009).

[3] NP EN 12390-1, Testing hardened concrete. Part 1: Shape, dimensions and other requirements for specimens and moulds, (2012).

[4] M. Hunger, A. G. Entrop, I. Mandilaras, H. J. H. Brouwers and M. Founti, The behavior of self compacting concrete containing micro-encapsulated phase change materials, Cement and Concrete Composites, Vol 31, no. 10,PP 731-743, (2009).

[5] Z. Zhang, G. Shi, S. Wang, X. Fang and X. Liu, Thermal energy storage cement mortar containing n-octadecane/expanded graphite composite phase change material, Renewable Energy, Vol 51, no. 0,PP 670-675, (2013).

[6] B. Xu and Z. Li, Paraffin/diatomite composite phase change material incorporated cement-based composite for thermal energy storage, Applied Energy, Vol 105, no. 0, PP 229-237, (2013).


Figures

Figure 1: Bending strength vs. displacement.

Figure 2: Temperature profile overtime of test specimens inside chamber.

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Elvira Fortunato, Rita Branquinho, Lídia Santos, Daniela Salgueiro, Luís Pereira, Pedro Barquinha, Rodrigo Martins CENIMAT/I3N, Departamento de Ciência dos Materiais, Faculdade de Ciências e Tecnologia, FCT, Universidade Nova de Lisboa (UNL), and CEMOP/UNINOVA, Portugal

[email protected]

T h i n f i l m t r a n s i s t o r s b a s e d o n m e t a l o x i d e s e m i c o n d u c t o r

t h i n f i l m s a n d n a n o p a r t i c l e s

Metal oxide conductors/semiconductors exhibit an intriguing combination of high optical transparency, high electron mobility, and in some cases amorphous microstructures.

Transparent electronics has arrived and is contributing for generating a free real state electronics that is able to add new electronic functionalities onto surfaces, which currently are not used in this manner and where silicon cannot contribute [1, 2]. The already high performance developed n- and p-type TFTs have been processed by physical vapour deposition (PVD) techniques like rf magnetron sputtering at room temperature which is already compatible with the use of low cost and flexible substrates (polymers, cellulose paper, among others). Besides that a tremendous development is coming through solution-based technologies very exciting for ink-jet printing, where the theoretical limitations are becoming practical evidences. In this presentation we will review some of the most promising new technologies for n- and p-type thin film transistors based on oxide semiconductors either in the form of thin films or nanoparticles.

Acknowledgments This work was funded by the Portuguese Science Foundation (FCT-MEC) through the projects EXCL/CTM-NAN/0201/2012 and PEst-C/CTM/LA0025/2013-14, and the European projects: ERC 2008 Advanced Grant (INVISIBLE contract number 228144), ORAMA CP-IP 246334-2 and POINTS NMP 263042.

References

[1] E. Fortunato, P. Barquinha, and R. Martins,

"Oxide Semiconductor Thin-Film Transistors: A Review of Recent Advances," Advanced Materials, vol. 24, pp. 2945-2986, Jun 2012.

[2] P. Barquinha, R. Martins, L. Pereira and E. Fortunato, Transparent Oxide Electronics: From Materials to Devices. West Sussex: Wiley & Sons (March 2012). ISBN 9780470683736.

Figures

Figure 1: a) GIZO TFT produced by rf sputtering at room temperature b) GZTO TFT produced by combustion synthesis at 250 °C; c) Electrolyte-gated TFT based ZnO nanoparticles annealed at 250 °C.


Angelos Giannakopoulos, C. Christodoulou, M. V. Nardi, G. Ligorio, M. Oehzett, L. Chen, G. Heimel, R. Ovsyannikov, L. Pasquali, M. Timpel, O. Monti, A. Giglia, S. Nannarone, K. Parvez, M. Linares, P. Norman, K. Muellen, D. Beljonne, N. Koch Laboratory for Chemistry of Novel Materials, University of Mons, Belgium

[email protected]

W o r k f u n c t i o n T u n i n g o f G r a p h e n e w i t h O r g a n i c

M o l e c u l e s

Graphene has conquered the field of Cutting Edge Technology as the ultimate next generation material. However, in order to be used widely in applications, one should be able to tune its electronic properties (i.e. work function). This may be achieved by deposition of electron acceptor or donor molecules on the surface of Graphene. In this work, we investigate the interaction between Graphene and an organic molecule, hexaazatriphenyl hexacarbonitrile (HATCN). HATCN is a strongly electron deficient molecule widely used in organic LEDs for hole injection [1,2]. By means of first principle computational techniques, we study the evolution in the work function of Graphene due to the adsorption of HATCN, as a function of the relative orientation and density of the doping molecules. Our modeling work points to a change from a lying-down to a standing-up configuration as the coverage increases, which is also observed in

HATCN layer growth experiment over gold(111) and silver(111) surfaces [3,4]. The preferential standing-up configuration is confirmed by simulated Near Edge X-ray Absorption Fine Structure Spectra (NEXAFS) in excellent agreement with experimental data. References

[1] L. S. Liao et al.; Adv. Mater. 20 (2008) 324–329 [2] L. S. Liao et al.; Applied Physics Letters 92 (2008)

223311 [3] P. Frank et al.; Chemical Physics Letters 473

(2009) 321–325 [4] P. Frank et al.; J. Phys. Chem. C 114 (2010)

6650–6657


Gomes, J.F.1,2, Albuquerque, P.C.3,

Esteves, H.M.4, Carvalho, P.A.5 1ISEL – Instituto Superior de Engenharia de Lisboa, Portugal 2IBB – Instituto de Biotecnologia e Bioengenharia, Portugal 3ESTESL – Escola Superior de Tecnologias de Saúde de Lisboa, Portugal 4INAIR, Portugal 5Departamento de Bioengenharia, Universidade Técnica de Lisboa, Portugal

[email protected]

N o t i c e o n a m e t h o d o l o g y f o r m o n i t o r i n g u l t r a f i n e

p a r t i c l e s / n a n o p a r t i c l e s i n m i c r o e n v i r o n m e n t s

The influence of very ultrafine particulate, lying in the nano range, on human health has already been reported to be of much concern as airborne nanoparticles can result both from nanotechnologies processes as well as from macroscopic common industrial processes such as granulated materials handling and metals processing.

Bearing in mind the potential adverse health effects of ultrafine particles it is of paramount importance to perform effective monitoring of nano sized particles in several microenvironments, which may include ambient air, indoor air and also occupational environments. In fact, effective and accurate monitoring is the first step to obtain a set of data that could be used further on to perform subsequent evaluations such as risk assessment and epidemiologic studies, thus proposing good working practices such as containment measures in order to reduce occupational exposure.

At this time, occupational health risks associated with manufacturing and use of nanoparticles are not yet clearly and fully understood. However, workers may be exposed to nanoparticles through inhalation at levels that can greatly exceed ambient concentrations.

Current workplace exposure limits, that have been established long ago, are based on particle mass criteria. However, this criteria does not seem adequate in what concerns nanoparticles as these materials are, in fact, characterized by very large surface areas, which are, in fact, the distinctive characteristic that could even turn out an inert

substance into another substance, having the same chemical composition, but exhibiting very different interactions with biological fluids and cells, which may become beneficial or not. Therefore, it seems that assessing human exposure based only on the mass concentration of particles, which is widely adopted for particles over 1 µm, could not be adequate for this particular case. As a matter of fact, nanoparticles have far more surface area for its equivalent mass of larger particles, which increases the chance they may react with body tissues. Thus, a growing number of experts have been claiming that surface area should be used instead for nanoparticle exposure and dosing. As a result, assessing workplace conditions and personal exposure based on the measurement of particle surface area is becoming of increasing interest. It is well known that lung deposition is the most efficient way that airborne particles can enter the body and potentially cause adverse health effects. Properties that contribute to the toxic effects of nanoparticles include: solubility, particle morphology, particle size, composition, surface chemistry, surface coatings and surface area. If nanoparticles can deposit in the lung and remain there, have an active surface chemistry and interact with the body, then, there is some potential for exposure and dosing. Oberdörster showed that surface area plays an important role in the toxicity of nanoparticles and this is the measurement metric that best correlates with particle-induced adverse health effects. The potential for adverse health effects seems to be directly proportional to particle surface area.

This paper presents an useful methodology for monitoring ultrafine particles/nanoparticles in


several microenvironments, using on-line analyzers and also sampling systems that allow further characterization on collected nanoparticles. This methodology was validated in some case studies that are presented in the paper which are the monitoring of nano sized particles in outdoor atmosphere and in a welding workshop, and seems to be effective for monitoring ultrafine particles in the above mentioned environments (being indoor or even outdoor) as well in other similar situations. The use of these equipment and experimental procedure provides very useful information for assessment of exposure as well as for risk assessment also. The obtained information can be

easily related with specific process conditions and physical constraints and, therefore, helps in the determination of the real origin of the airborne ultrafine particles, and also to the definition of appropriate containment measures for emitted nanoparticles and good operational practices in order to reduce occupational exposure.

Figure 1 shows obtained TEM images of collected ultrafine particulate during MAG welding using gas mixture Ar+18% CO2 (top) and Ar+8% CO2 (bottom).

Figures

Figure 1: TEM images of collected ultrafine particulate during MAG welding using gas mixture Ar+18% CO2 (top) and Ar+8% CO2 (bottom).


Gonçalves, C.1, Antunes, I. F. 2,

Lalatonne, Y.3, Ferreira, M.F.M.4, Geraldes, C.F.G.C.5, Motte, L.3,Martins, J.A.4, de Vries, E. F. J.2,Gama, F.M.1 1IBB-Institute for Biotechnology and Bioengineering, Portugal 2Dept. of Nuclear Medicine and Molecular Imaging, University of Groningen, The Netherlands 3CSPBAT Laboratory, UMR 7244 CNRS, France 4Chemistry Department, Minho University, Portugal 5Departamento de Ciências da Vida, Universidade de Coimbra, Portugal

[email protected]

N e w d e x t r i n n a n o m a g n e t o g e l s : p r o d u c t i o n , c h a r a c t e r i z a t i o n

a n d i n v i v o p e r f o r m a n c e a s d u a l m o d a l i t y i m a g i n g

b i o p r o b e

Dual modality contrast agents, such as radiolabelled magnetic nanoparticles, are promising candidates for a number of diagnostic applications, since they combine two complementing imaging modalities, namely photon emission computed tomography (SPECT) and magnetic resonance imaging (MRI). The benefit of such combination lies on the ability to interpret more accurately abnormalities in vivo, by integrating the high sensitivity of SPECT with the superb spatial resolution and anatomical information provided by MRI [1]. Superparamagnetic iron oxide nanoparticles (SPION) have been extensively studied as MRI contrast agents [2]. SPIONs need to be coated in order to allow formulation in aqueous solutions and to increase in vivo stability [3].

Dextrin nanomagnetogels consists on superparamagnetic iron oxide nanoparticles (ɣ-Fe2O3) stabilized within hydrophobized-dextrin nanogel (scheme 1). The nanomagnetogel formulation, with about 4 mM of iron and a diameter of 100 nm, presents relevant features such as superparamagnetic behaviour, high stability, narrow size distribution and potential for magnetic guidance to target areas by means of an external magnetic field [4]. The functionalization of the dextrin nanomagnetogel with a DOTA-monoamide ω-thiol metal chelator and radiolabelling with 111In were used to ascertain its in vivo stability and behavior (blood clearance rate and organ distribution) after intravenous administration in mice model. The surface modification of the nanomagnetogel with PEG 5,000 was accomplished in an attempt to escape the phagocytic system. The unloaded radiolabeled dextrin nanogel (around 30 nm) showed lower uptake in the liver, spleen and kidneys than the

nanomagnetogel loaded with SPIONs (around 110 nm). This difference in biodistribution profile can be ascribed to the differences in the particle size.

Nanomagnetogel pegylation resulted in lower liver and spleen accumulation. The blood half-life obtained was approximately 4 hours for all formulations. A good correlation between the amount of polymer (quantified through radioactivity) and the amount of iron (ICP measurement) in the spleen was observed, indicating that leakage of iron from the nanomagnetogels after intravenous administration was negligible. The pilot imaging study demonstrated good performance of dextrin nanomagnetogels as dual modality imaging (MRI and SPECT) bioprobes as expected by the high transverse relaxivity (215-248 mM-1s-1) obtained in vitro, higher than those of commercial available formulations (160-177 mM-1s-1). The production of the nanomagnetogel is simple and easy to scale up, thus offering great technological potential.


References

[1] R. Misri, D. Meier, A. C. Yung, P. Kozlowski, U. O. Hafeli, Nanomedicine, 8 (2012) 1007. [2] X. H. Peng, X. M. Qian, H. Mao, A. Y. Wang, Z. Chen, S. M. Nie, D. M. Shin, International Journal of

Nanomedicine, 3 (2008) 311. [3] W. Yu, E. Chang, C. M. Sayes, R. Drezek, Colvin V.L., Nanotechnology, 17 (2006) 4483. [4] C. Gonçalves, Y. Lalatonne, L. Melro, G. Badino, M. F. M. Ferreira, L. David, C. F. G. C. Geraldes, L. Motte, J.

A. Martins, F. M. Gama, J. Mater. Chem. B, DOI:10.1039/C3TB21063D (2013).

Figures

Scheme 1. Schematic dextrin nanomagnetogel as dual modality imaging bioprobe (MRI and SPECT).


J. Rafaela Guerreiro, Maj Frederiksen, Vladimir Bochenkov, Victor De Freitas,M. Goreti Sales and Duncan S. Sutherland BioMark Sensor Research/ISEP, Rua Benardino de Almeida 4200-072 Porto, Portugal. Centro de Investigação em Química, Faculdade de Ciências, UP, Rua do Campo Alegre, 4169-007 Porto, Portugal Interdisciplinary Nanoscience Center (iNANO), Gustav Wieds Vej 14, 8000 Aarhus Denmark

[email protected]

A s t r i n g e n c y e s t i m a t i o n b y L o c a l i z e d S u r f a c e P l a s m o n

R e s o n a n c e

The popularity of phenolic compounds has increased in the past years due to their antioxidant capacity and association for the prevention of heart diseases 1, chronic inflammation 2 and cancer 3.

Human diet is the main source of polyphenols provided by products derivate from plants such as fruits, vegetables and beverages, and the long term consumption suggests a contribution for potential health benefits. In addition, polyphenols also contribute for the sensorial perception of food products being astringency one of the known sensory characteristics.

Astringency is a mechanism that is still not fully understood. Nevertheless, several studies support the concept that astringency is a tactile sensation rather than a taste. The astringency mechanism is thought to be caused by the polyphenols ability to bind salivary proteins, thus forming complexes that lead to precipitation by promoting the dryness roughening and pucker typical perceived. Furthermore astringency is also an important parameter used to determine the wine quality and it is usually estimated based on sensorial panels which are expensive, time consuming and conferring a certain subjectivity to the process 4.

In order to overcome these disadvantages, a label free sensory system was performed based on localized surface plasmon resonance (LSPR) by detecting the interaction between a salivary protein and the polyphenols, mimicking the natural interaction which occurs in the mouth. The LSPR is a powerful tool because the metallic nanostructures can be excited by incident light, thereby promoting a collective oscillation of the conduction electrons at a

specific wavelength. Structural changes in the local refractive index are induced, when the target molecules bind to the receptor on the surface of a nanoplasmonic, those being tracked by the monitorization of variations at the correspondent wavelength of maximum extinction.

The nanostructures used in this work were gold nanodisks attached to a glass surface fabricated by sparse colloidal lithography. The substrates were prepared according to the following steps : i) cleaning the glass coverslips; ii) spin coating of PMMA, followed by 2 min. in a hot plate; iii) deposition of a triple layer of polyelectrolytes for 30 min each followed by the deposition of polystyrene particles 100 nm size; iv) deposition of 20 nm Ti as a mask; v) removal of particles by tape stripping followed by etching for 10 min vi) deposition of 2 nm Ti and 20 nm Au followed by acetone rising. The resultant nanostructures were gold nanodisks as shown in figure 1. After the fabrication of gold disks, α-amylase was immobilized on the gold surface according to the optimal conditions previously tested, and the subsequent interaction with pentagalloyl glucose (PGG) was measured by LSPR. The interacting between the polyphenol PGG and the immobilized alpha-amylase displayed a red shift in the spectra which kept shifting with the increasing of PGG concentration as can be seen in figure 2. The interaction between the polyphenol and the salivary protein provided a linear behavior for a concentration range from 0.5 to 155 μM of PGG, which can be seen in figure 3. Red wine samples which were previously analyzed by a sensory panel were also measured and classified in terms of astringency. The wine astringency presented the same order of astringency levels when compared


with the sensory panel, indicating the close agreement between both methodologies.

Therefore the proposed sensor offers a simple approach for the estimation astringency based on protein-polyphenol interaction, being the application to real samples successful.

Additionally the LSPR nanostructure enhanced the sensing ability and included a simple fabrication due to the recent advances in nanotechnology. References

[1] R. M. Pollack and J. P. Crandall, American

Journal of Hypertension, 2013, 26, 1260-1268. [2] D. Serra, J. Paixao, C. Nunes, T. C. P. Dinis and L.

M. Almeida, Plos One, 2013, 8. [3] S. Santos, B. M. Ponte, P. Boonme, A. M. Silva

and E. B. Souto, Biotechnology Advances, 2013, 31, 514-523.

[4] V. de Freitas and N. Mateus, Current Organic Chemistry, 2012, 16, 724-746.

Figures

Figure 1: Side view of the fabricated gold nanodiscs.

Figure 2: LSPR peak shift according resulting from the interaction of the salivary protein with the increasing concentrations of PGG (polyphenols).

Figure 3: Linear correlation between immobilized alpha-amylase and PGG (polyphenol) on the surface of gold nanodiks.


Rui Gusmão1,2,4 Vanesa López-Puente3,

Isabel Pastoriza-Santos3, Jorge Perez-Juste3 and Elisa Gonzalez-Romero4 1Centro de Química, Universidade do Minho, Portugal 2Instituto de Polímeros e Compósitos, Universidade do Minho, Portugal 3Departamento de Química Física, Universidad de Vigo, Spain 4Departamento de Química Analítica y Alimentaria, Universidad de Vigo, Spain

[email protected]

A u N a n o p a r t i c l e s b u i l t - i n M e s o p o r o u s T i O 2 C o m p o s i t e f o r V o l t a m m e t r i c D e t e c t i o n

Over the past years, self-organizing electrochemical methods have been greatly refined to prepare highly ordered metal oxide structures with various morphologies such as nanopores [1], nanotubes [2] or nanoshells [3] on metals such as Ti [4]. In view of direct functional applications, anodic TiO2 nanotubes have attracted in the last ten years by far the widest interest due to their facile fabrication process and their potential applications in a wide range of functional. On the one hand, investigations target a further increase in the control over defined tube geometries (tube length, wall thickness, diameter, and order). On the other hand, these directional high surface area structures are of interest in virtually any application where up to now TiO2 nanoparticles are used. Composite materials made of mesoporous Thin Titania Oxide Films (TF) containing metallic nanoparticles are of high interest in equally various fields, including catalysis, biosensing and non-linear optics [6-8].

Recently, V. López-Puente et al. [8] have developed the methodology for the fabrication of such composite materials onto glass slides containing a submonolayer of gold nanoparticles (AuNPs) with mesoporous Pluronic F127 TF and its application as a novel surface-enhanced Raman scattering (SERS) substrate. Comprising a submonolayer of AuNPs covered with a mesoporous thin film, which can act as a molecular sieve by size exclusion and avoid contamination of SERS spectra in biological media. The seeded growth of the nanoparticles through the mesoporous film allowed the formation of sharp tips, which improved the SERS efficiency of the material. The obtained composite materials combine the interesting optical properties of metal

nanoparticles with the filtering ability and chemical stability of mesoporous TF films [8, 9].

We have applied this procedure onto a conductive material such as carbon and the characterization of the surface by SEM was carried out (Figure 1). We also present the study of screen printed carbon electrodes (SPCE) modified with these composite films, comprising AuNP embedded in mesoporous Thin Titania Oxide Films (TF-AuNP) and with each of its different building blocks: TiO2, Pluronic F127 and AuNPs. The specific surface area of TF-AuNPs on SPCE can further enhance the electrochemical reaction of hydroxybenzenes (hydroquinone, catechol, pirogallol) and dopamine, an excitatory chemical neurotransmitter, leading to the increase of voltammetric sensitivity and selectivity (Figure 2). The present work explores an interesting and significant application TF-AuNP composite in electroanalysis and future prospects of its biosensing application.


References

[1] C.R. Martin, Science 266 (1994) 1961. [2] L. Pu, X.Zou, D.Feng, Angew. Chemie Int. Ed. 40

(2001) 1490. [3] D. Koktysh, X. Liang, B.-G. Yun, I. Pastoriza-

Santos, R.L. Matts, M. Giersig, C. Serra-Rodríguez, L.M. Liz-Marzán, N. A. K. Adv. Funct. Mater., 12 (2002) 255.

[4] K. Lee, D. Kim, P. Schmuki, Chem. Commun. 47 (2011) 5789.

[5] J. Yoo, K. Lee, A. Tighineanu, P. Schmuki, Electrochem. Commun. 34 (2013) 177.

[6] K. McKenzie, F. Marken, Langmuir. 19 (2003) 4327.

[7] L. Kavan, J. Rathouský, J. Phys. Chem. B. 104 (2000) 12012–12020.

[8] V. López-Puente, S. Abalde-Cela, P.C. Angelomé, R.A. Alvarez-Puebla, L.M. Liz-Marzán, J. Phys. Chem. Lett. 4 (2013) 2715.

[9] E. Heydari, I. Pastoriza-Santos, J. Phys. Chem. C. 117 (2013) 16577.

Figures

Figure 1: SEM images of SPE carbon working electrode before (A) and after growth reaction (B) for 15 nm AuNP@TF samples and (C) Cyclic voltammograms in PBS 0.1 M (pH 7.4) at a scan rate of 100mV/s of 15 nm AuNP@TF samples before and after growth for electrochemical applications.

Figure 2: Cyclic voltammograms of dopamine 1 mM in PBS 0.1 M (pH 7.4) at the differently modified SPCEs, by cycling between -0.5 V and 0.5 V (three cycles) at a scan rate of 100 mV/s.


Daniel Hagmeyer and Hanno Wachernig Microtrac Europe GmbH, Am Latumer See 11, D-40668 Meerbusch, Germany

[email protected]

T o o l t o q u a n t i f y i o n i c a c t i v i t y o f m a c r o m o l e c u l e s a n d c h a r g e d e n s i t y o n p a r t i c l e i n t e r f a c e s

A new analysis tool is presented for the formulation of ionic macromolecules and charged particle interfaces. Ionic activity of macromolecules can be determined by titrating the ionic interface potential against a polyelectrolyte solution of known elementary charge content (“polyelectrolyte titration”). In figure1 a polyelectrolyte titration is presented as an example. By entering the weight, volume and molecular weight of the sample, a result is obtained in Cmol-1. The ionic loading of particles is measured by the same titration procedure. The result in volume consumption is recalculated as weight specific [Cg-1] or surface specific [Cm-2] charge. The latter is achieved by measuring the sample simultaneously with a DLS dynamic light scattering size probe.

The charge tiration is based on the streaming potential method offering a quickly reacting electrical signal. It is designed for formulation work, where reactions of ionic interfaces to environmental conditions like pH, ionic surfactants, salt or conductivity can be studied very efficiently. All polar media based samples, black and transparent, of low and high conductivity, from sub-nanometer up > 100 µm can be analyzed with this method. An upper concentration limit of 40%v gives room for many studies of undiluted samples.

As the size and concentration range of both methods, in-situ DLS sizing and streaming potential charge titration, almost overlap, the combination of both pairs ideally. From 180° DLS hydrodynamic size analysis, sample concentration and specific surface charge are derived. In many cases it helps to determine the critical coagulation point. A typical example of charge and size measured versus pH is shown in figure 2. It shows at which condition coagulation starts.

The streaming potential method although proven in wet paper process analytics, is less known in other

applications. Nevertheless it is very useful und capable of making new discoveries. In combination with the proven 180° DLS probe it offers even more ways for charge and size mapping of colloid samples.

Figures

Figure 1: A polyelectrolyte titration of a cationic polymer vs an anionic polyelectrolyte solution with known charge content. Depending on the calibration, the scaling of the potential can be in streaming potential – as shown here - or in zeta potential units – as shown in fig.2.

Figure 2: During a pH - charge titration on a 1%w Al2O3 titration, DLS size was measured in-situ. The size result demonstrates coagulation far before the isoelectric point is reached. The titration started at pH = 4.3.


Jae Seok Hwang and Dae Joon Kang BK21Plus Physics Research Division, Department of Energy Science, Institute of Basic Science, SKKU Advanced Institute of Nanotechnology, Sungkyunkwan University, Korea.

[email protected]

S y n t h e s i s o f T r a n s i t i o n M e t a l D i c h a l c o g e n i d e A t o m i c L a y e r

v i a a S u l f u r i z a t i o n R o u t e

Many researchers have tried to explore the unique physical and optical properties of transition metal dichalcogenides (TMDs). Especially, molybdenum disulfide (MoS2) has attracted a great attention as it is considered to be a promising alternative to replace graphene for many viable electronic applications. We designed a novel growth method for obtaining high quality MoS2 atomic layers based on thermodynamics and simple sulfurization method. We successfully synthesized a few-layer of ultra-large area MoS2 thin films a up to a few inch by a sulfurization route. We showed that the number of layer can be easily tuned by controlling the growth temperature and the growth duration.

Moreover, we developed a facile transfer technique for the transfer of as-synthesized MoS2 layers to other substrates including SiO2/Si substrates. We investigated their structural and optical properties by using X-ray diffraction, photoluminescence and Raman spectroscopy. Our results suggested that a simple sulfurization process can be exploited to obtain a few-layer of ultra-large area TDMs thin films. This may open up a great opportunity for the exploration of novel TMDs to many viable applications.

Figures

370 380 390 400 410 420

Inte

nsity(a

.u.)

Raman( cm-1)

490degree 20min


Wlodzimierz Jaskólski, Leonor Chico, Andres Ayuela, and Marta Pelc Institute of Physics, Nicolaus Copernicus University, Grudziadzka 5, Poland Instituto de Ciencias de Materiales de Madrid, CSIC, Madrid, Spain Centro de Física de Materiales, CFM-MPC CSIC-UPV/EHU, Donostia International Physics Center, San Sebastian, Spain

[email protected]

T h e r o l e o f o c t a g o n a l d e f e c t s i n t h e e l e c t r o n i c p r o p e r t i e s o f

g r a p h e n e n a n o r i b b o n s a n d c a r b o n n a n o t u b e s

Graphene grown in the laboratory presents structural defects and grain boundaries, which have been observed with various experimental techniques. Topological defects are also common at junctions between different carbon nanotubes. Defects and grain boundaries focus recently a lot of interest because they can strongly influence the transport and magnetic properties of graphene-based products and devices. Here, we investigate the electronic properties of several graphene structures containing defects built of octagonal rings. These rings are commonly present at grain boundaries and defect lines in graphene [1,2], but they also occur at locally isolated and reconstructed divacancies [3,4]. Octagonal defects may also appear at strongly curved graphene or at diagonal junctions between carbon nanotubes.

We summarize our very recent findings concerning octagonal defects at (a) junctions between zigzag graphene nanoribbons [5], (b) diagonal junctions between zigzag carbon tubes [6], and (c) isolated divacancies in graphene ribbons and carbon nanotubes [7]. We work in the π-electron tight-binding approximation and the electron interaction effects are taken into account by the Hubbard model. The junction between zigzag graphene ribbons (case a) has a form of a defect line built of octagons or octagons accompanied by pentagon pairs. We show that the octagon-localized states, with energies at the Fermi level (see Fig.1), can be univocally derived from the edge states of the zigzag nanoribbons [8]. This is because the octagons in defect lines show up only as the result of the specific shape of the joined edges. Additionally, the results

of Hubbard calculations reveal that junctions built of octagons may show spontaneous magnetization. The isolated octagonal defects (cases b and c) also lead to the appearance of states at the Fermi energy. By disconnecting such octagons from the graphene network we are able to explain the origin of the defect-localized states. We prove that they are directly related to the doubly degenerate zero-energy levels of carbon rings forming the octagonal topological defects (see Fig. 2). In the case of isolated divacancies, the octagons are accompanied by a pair of pentagons. Since the pentagons mix the graphene sublattices, the energies of the defect-localized states are shifted from the Fermi level. In the wide-gap semiconducting graphene ribbons or carbon nanotubes tubes, the defect-localized states may appear in the energy gap and can act as acceptor or donor states (see Fig.3).


References

[1] P.Y. Huang, C.S. Ruiz-Vargas, A.M. van der

Zande, W.S. Whitney, M.P. Levendorf, J.W. Kevek, S. Garg, J.S. Alden, C.J. Hustedt, Y. Zhu, J. Park, P.L. McEuen, D.A. Muller, Science 469 (2011) 389.

[2] J. Lahiri, Y. Lin, P. Bozkurt, I. I. Oleynik, and M. Batzill, Nat. Nanotechnol. 5 (2010) 326.

[3] A. W. Robertson, C. S. Allen, Y. A. Wu, K. He, J. Olivier, J. N., A. I. Kirkland and J. H. Warner, Nature Communications 3 (2012) 1144.

[4] J. Kotakoski, A. V. Krasheninnikov, U. Kaiser, J. C. Meyer, Phys. Rev. Lett. 106 (2011) 105505.

[5] M. Pelc, L. Chico, A. Ayuela, W. Jaskolski, Phys. Rev. B, 87 (2013) 165427.

[6] W. Jaskolski, M. Pelc, L. Chico, A. Ayuela, Sci. World J., 2013 (2013) http://dx.doi.org/10.1155/2013/658292

[7] M. Pelc, W. Jaskolski, A. Ayuela, L. Chico, Acta Phys. Pol. (2013) in press

[8] W. Jaskolski, A. Ayuela, M. Pelc, H. Santos, L. Chico, Phys. Rev. B 83 (2011) 235424.

Figures

Figure 1: (a) Local density of states (LDOS) at the interface between two zigzag graphene half planes; the junction constitutes a defect line built of octagons and pentagon-pairs. (b) LDOS at the interface between two (8,0) nanotubes with an octagon–pentagon-pair junction. Flat band and peaks at EF correspond to the states localized at octagons.

Figure 2: (a) Schematic diagonal junction between zigzag (8,0) and (14,0) nanotubes. The circles mark the positions of the octagonal defects. (b) Local density of states (LDOS) at the nanotube junction. The peak at EF is doubly degenerate and corresponds to the octagon-localized states.

Figure 3: (a) Geometry and (b) local density of states (LDOS) of the armchair nanoribbon with single divacancy reconstructed to the 5-8-5 defect. The nanoribbon extends horizontally. The gap states originate from octagonal ring. The Fermi level is between the gap states.


Frank Koppens ICFO, Spain

[email protected]

G r a p h e n e q u a n t u m n a n o -o p t o e l e c t r o n i c s

Optics and opto-electronics of graphene is one of most vibrant, rapidly developing and exciting areas which has already led to some commercial applications. Rather than being just another new photonic material, it combines a wide palette of unique aspects which promise breakthroughs in several outstanding problems of nanophotonics and optoelectronics, including broadband photodetection and sensing, on-chip manipulation of nanoscale optical fields and lasing.

In this talk, the most recent developments of graphene nano-photonics and photoconversion for near-infrared and infrared frequencies are being reviewed. Strong interactions between graphene and nanoscale light-emitters are controlled and detected by tuning graphene from an absorbing to plasmonic material. Additionally, we discuss the role of electron interactions on the photoconversion processes. Using techniques from solid-state cavity quantum electrodynamics (QED) to strongly couple graphene to optical fields, we discuss new avenues in quantum information processing, imaging, and sensing.

Figures


Galder Kortaberria, Haritz Etxeberria, Arantxa Eceiza

“Materials + Tecnologies” Group, Basque Country University, Plaza Europa 1, 20018 Donostia/San Sebastian, Spain

[email protected]

N a n o c o m p o s i t e s b a s e d o n S B S t r i b l o c k c o p o l y m e r a n d

s e l e c t i v e l y p l a c e d P S - g r a f t e d C d S e n a n o p a r t i c l e s

CdSe nanoparticles synthetized by aqueous method were functionalized with polystyrene (PS) brushes (CdSe-PS) by grafting through method [1, 2].

Then they were used to prepare nanocomposites by adding different amounts (3, 5 and 10 wt%) to a poly (styrene-b-butadiene-b-styrene) (SBS) triblock copolymer [3, 4]. Atomic force microscopy (AFM) and electrostatic force microscopy (EFM) [5] were used for morphological and electrical characterization of SBS/CdSe-PS nanocomposites. AFM images showed a good dispersion of the nanoparticles in the block copolymer, with the placement of the nanoparticles in the PS domains due to the improved affinity obtained by their functionalization with PS brushes.

EFM showed that nanoparticles maintained their conductive properties even after being modified and embebbed in the block copolymer.

Acknowledgements: Financial support from the Basque Country Government (NanoIker IE11-304, Grupos Consolidados IT776-13, Saiotek2012-SPE12UN106) and from the Ministry of Education and Innovation (MAT2012-31675) is gratefully acknowledged.

References

[1] H. Etxeberria, G. Kortaberria, I. Zalakain, A.

Larrañaga, I. Mondragon. Journal of Materials Science, 47 (2012) 7167.

[2] H. Etxeberria, I. Zalakain, A. Tercjak, I. Mondragon, G. Kortaberria. Journal of Nanoscience and Nanotechnology 13 (2013) 643.

[3] H. Etxeberria, I. Zalakain, A. Eceiza, G. Kortaberria. Journal of Colloid and Polymer Science 291 (2013) 1881.

[4] H. Etxeberria, R. Fernandez, I. Zalakain, I. Mondragon, G. Kortaberria. Journal of Colloid and Polymer Science 291 (2013) 633.

[5] H. Etxeberria, I. Zalakain, A. Tercjak, A. Eceiza, G. Kortaberria. Journal of Colloid and Polymer Science (2013) DOI 10.1007/s00396-013-3061-3.

[6] M. Gobbi, et al., Applied Physics Letters 101 (2012) 102404

Figures

Figure 1: Reaction scheme for the modification of CdSe nanoparticles with PS brushes

Figure 2: AFM image (left/right: height/phase) for 10 wt % SBS/PS-CdSe composite

Figure 3: EFMimage (left/center/right height/EFMphase (0 V)/EFMphase (−6 V)) for CdSe-PS


Igor Kuzmenko1, Yshai Avishai1,2

1Department of Physics, Ben-Gurion University of the Negev, Beer-Sheva, Israel 2Department of Physics, Hong Kong University of Science and Technology, Kowloon, Hong Kong

[email protected]

E x o t i c K o n d o E f f e c t i n C a r b o n N a n o t u b e Q u a n t u m D o t

We study the Kondo effect in a CNT(left lead)-CNT(QD)-CNT(right lead) structure. Here CNT is a single-wall metallic carbon nanotube, for which 1) the valence and conduction bands of electrons with zero orbital angular momentum (m=0) coalesce at the two valley points K and K' of the first Brillouin zone and 2) the energy spectrum of electrons with m≠0 has a gap whose size is proportional to |m|. Following adsorption of hydrogen atoms and application of an appropriately designed gate potential, electron energy levels in the CNT(QD) are tunable to have: 1) two-fold spin degeneracy; 2) two-fold isospin (valley) degeneracy; 3) three-fold orbital degeneracy m=0,±1. This exotic Kondo effect is analyzed within poor-man scaling (in the weak coupling regime) and within the mean field slave boson formalism (in the the strong coupling regime). It is shown that the Kondo temperature TK for the SU(12) Kondo effect is much higher than in the standard SU(2) Kondo effect. The pertinent tunnel conductance has the similar temperature dependence as for the usual SU(2) Kondo effect. On the other hand, a peculiar result related to the SU(12) symmetry is that the magnetic susceptibilities for parallel and perpendicular magnetic fields display anisotropy

with a universal ratio that depends only on the g factors. The non-linear tunneling conductance at temperature T and source-drain voltage V in the weak coupling regime T>TK is calculated in perturbation theory with the result,

where and n=12 The zero-bias differential conductance is shown in Figure 1, left

panel. It is seen that the conductance increases when the temperature decreases which is also characteristic of the standard SU(2) Kondo tunneling through a semiconductor quantum dot [1,2]. On the other hand, a peculiar result related to the SU(12) symmetry [and absent in the ordinary SU(2)] Kondo effect is related to magnetic response. Specifically the magnetic susceptibilities for parallel and perpendicular magnetic fields [with respect to the CNT axis] display anisotropy [3] with a “universal” ratio. In more detail, let us write the magnetic susceptibility tensor as, where or is the susceptibility of the junction for the magnetic field parallel or perpendicular to the CNT axis. The magnetic susceptibility as function of temperature (in the weak coupling regime) is shown in Figure 2, right panel. From this we see that the susceptibility for the SU(12) Kondo tunneling is anisotropic, whereas the susceptibility for the standard SU(2) Kondo tunneling is isotropic [2]. Moreover, it is found that the ratio

is independent on temperature, but only on the spin and orbital g factors. This might be a way to experimentally identify the SU(12) Kondo effect. References

[1] A. Kaminski, Yu. V. Nazarov and L.I. Glazman,

Phys. Rev. B 62 (2000) 8154. [2] A.C. Hewson, The Kondo Problem to Heavy

Fermions, (Cambridge University Press, 1993). [3] H. Ajiki and T. Ando, J. Phys. Soc. Jpn. 62 (1993)

1255.


Figures

Figure 1: Figure 1: CNT(left lead) - CNT(QD) - CNT(right lead) junction.

Figure 2: The zero-bias conductance (left panel) and the impurity susceptibility (right panel) as function of temperature in the weak coupling regime [T>TK].


I A Larkin1 and S S Vergeles2

1Department of Physics, Minho University, Braga 4710-057, Portugal 2Landau Institute for Theoretical Physics, Chernogolovka, Russian Federation.

[email protected]

L i g h t T r a n s m i s s i o n a n d R e f l e c t i o n f r o m a T h i n

M e t a l l i c F i l m

We consider the transmission of an electromagnetic wave through a thin (nanometer scale) metallic film. The thickness of the film is assumed to be much smaller than the electromagnetic wavelength and the mean free path of Fermi electrons. To solve this problem we treat the electrons in the metal as a charged degenerate Fermi liquid. Electronic motion inside the metal is governed by Boltzmann’s kinetic equation [1].

(1) where f (r, p, t)= f0 + δf is the perturbed distribution function and f0 is the distribution function at equilibrium. We normalize the distribution function according to

where n(r, t) is the local electronic density. Inside the film the electric field can be defined by a potential distribution: E = −∇Φ. Let us also assume the temperature to be much lower than the Fermi energy ϵF. We introduce a new function χ(r,p,t), which describes the deviation of the distribution function from the equilibrium according to the equation δf(r,p,t) = ϵF •∂ϵ f0 •χ(r,p,t)

The potential inside the film satisfies the equation

(2) Equations (1) and (2) form a self-consistent system that determines the amplitude of the electric field inside the film [2]. Together with boundary conditions it gives the complex Fresnel coefficients for transmission and reflection.

References

[1] A.A. Abrikosov, Fundamentals of the theory of

metals, (North-Holland, 1988) [2] I.A. Larkin and M.I. Stockman, Nano letters, 5,

(2005), 339


Lifeng Liu and Xiao-Qing Bao International Iberian Nanotechnology Laboratory (INL), Av. Mestre Jose Veiga, Braga, Portugal

[email protected]

S i l i c o n B a s e d M a t e r i a l s F o r H y b r i d S o l a r C e l l s a n d

P h o t o e l e c t r o c h e m i c a l C e l l s

Solar energy is thought to be the only renewable energy source to have potential to provide alone the 10 – 20 TW carbon-neutral energy needed in 2050 in order to avoid the likely most serious consequences of global climate change.[1] In the past decades, vast research efforts have been devoted to developing highly efficient and low cost solar energy harvesting devices including solar cells (for solar-electrical energy conversion) and photoelectrochemical cells (PECs, for solar fuel production). Among the various materials investigated so far, silicon (Si) is still one of the most promising semiconducting materials for use in both solar cells and PECs because it is earth-abundant and has a broad-band adsorption. In this talk, two types of energy harvesting devices based on planar Si and Si nanostructures will be presented, namely, 1) Si/PEDOT:PSS hybrid solar cells and 2) ordered Si nanobelt array based PECs for solar hydrogen generation.

Usually, the Si/PEDOT:PSS solar cells only exhibit low power conversion efficiency in case hydrogen-terminated Si (Si:H) is used. We recently found that by intercalating a layer of platinum nanoparticles (Pt NPs) between Si:H and the PEDOT:PSS layer, the cell’s photovoltaic (PV) performance can be markedly improved.[2] In addition to the current-voltage (J-V) characteristics and photocurrent action spectrum (IPCE) characterization, unconventional techniques such as impedance spectroscopy, Mott-Schottky analysis and intensity modulated photocurrent/photovoltage spectroscopy were also used to clarify the underlying mechanism

responsible for the PV performance enhancement. The results show that a Pt NP interlayer intercalated between the Si:H and PEDOT:PSS is able to reduce the series resistance and charge transfer resistance giving rise to an increased short circuit current density, to raise the built-in voltage at the space charge region facilitating charge separation, and to effectively suppress p-n interface recombination, thereby improving the cell’s overall PV performance.

Besides, well-ordered tilted Si nanobelt arrays were fabricated over a large area by cost-effective metal assisted chemical etching of pre-patterned Si substrates.[3] Compared with planar Si of the same type, the tilted Si nanobelt arrays exhibit markedly enhanced photocurrent density for hydrogen evolution and much faster charge transfer kinetics at the electrode/electrolyte interface, which can be attributed to the unique structural feature of the array which allows more incident light to be absorbed and the remarkably increased surface area, respectively. The stability of the Si nanobelt array photocathodes was investigated as well.

References

[1] N.S. Lewis, MRS Bull., 32 (2007) 808. [2] X.Q. Bao, L.F. Liu, submitted [3] X.Q. Bao, R. Ferreira, E. Paz, D.C. Leitao, A. Silva,

S. Cardoso, P.P. Freitas and L.F. Liu, Nanoscale, Accepted

Figure 1: SEM micrograph showing the morphology of the well-orderd Si nanobelt arrays (left) and J-V characteristics of the Si nanobelt array photocathode for solar hydrogen evolution.


Jordi Llop Roig Molecular Imaging Unit, CIC biomaGUNE, San Sebastian, Spain

[email protected]

R a d i o l a b e l l i n g o f n a n o p a r t i c l e s f o r n a n o s a f e t y

e v a l u a t i o n : d i r e c t b e a m a c t i v a t i o n

Due to their small size and high surface area, metal and metal oxide nanoparticles (NPs) have interesting and unique properties that differ from bulk phase materials. Consequently, they are ubiquitously utilized as food or paint additives, in the construction and semi-conductor industries, cosmetic applications, solar cells, and in many other industrial and societal sectors. The increased use of metal and metal oxide NPs has raised many concerns about potential risks for human health. However, the investigation of the potential toxicological effects and biological fate of the NPs after incorporation into biological systems is extremely challenging because they are very difficult to detect in vivo. In addition, many detection methods do not rely on the identification of nanoparticulate materials, but rather on the individual chemical components present in the NPs. As a consequence, natural or background levels of such components may mistakenly be considered as a sign of NP presence.

One possibility to overcome this problem is by labelling the NPs with radionuclides that can lead to their detection in biological systems by means of ultra-sensitive in vivo imaging techniques such as Positron Emission Tomography (PET) or Single Photon Emission Computerized Tomography (SPECT). However, the incorporation or attachment of a radionuclide to the NPs without introducing significant modifications of the physicochemical and morphological properties of the NPs is not trivial.

NPs can be radiolabelled by a variety of methods, including: (i) chemical surface attachment of a radiotracer via a linking and/or chelating molecule; (ii) synthesis of the NPs using radiolabelled precursors; (iii) diffusion of radioisotopes into the NPs; (iv) direct neutron activation; (v) direct ion-beam activation and (vi) recoil implantation of radionuclides. The appropriate method should be selected by considering aspects such as the physicochemical and surface properties of the NPs, NP size, the detection technique to be employed and the duration of the study, among others. In the context of nanosafety and metal or metal oxide NPs, direct beam activation methods are considered valuable strategies because they allow the activation and investigation of the industrial materials themselves without modifying (a priori)

their bulk and surface characteristics, or their state of aggregation or agglomeration. In this presentation, a brief overview of the different methods for radiolabelling NPs using beam activation will be provided. The pros and cons of each strategy will be discussed and specific examples based on published data and personal experience will be presented. Finally, application of radiolabelled NPs for determining their biodistribution pattern in experimental animals using nuclear imaging techniques, as well as different administration routes, will be provided.


Nicolò Maccaferri1, Andreas

Berger1, Stefano Bonetti2, Valentina Bonanni3, Mikko Kataja4, Sebastiaan van Dijken4, Josep Nogués5, 6, Johan Åkerman7, Zhaleh Pirzadeh8, Alexandre Dmitriev8 and Paolo Vavassori1, 9 1CIC nanoGUNE Consolider, Spain 2SIMES, SLAC National Accelerator Laboratory, USA

3University of Florence & INSTM, Italy 4NanoSpin, Finland 5ICN2, Spain 6ICREA, Spain 7KTH Royal Institute of Technology, Sweden and University of Gothenburg, Sweden 8Chalmers University of Technology, Sweden 9IKERBASQUE, Spain

[email protected]

P l a s m o n i c p h a s e t u n i n g o f m a g n e t o - o p t i c s i n

f e r r o m a g n e t i c n a n o s t r u c t u r e s

Electromagnetic scattering from metallic nanometer-scale particles is currently a topic of huge interest. The vast majority of these studies is performed on noble-metal nanostructures and is focused on the effects on the scattered field due to the nano-confinement of electric fields caused by the excitation of localized plasmon resonances in single nanoparticles. In the last years the research efforts moved on magnetoplasmonic nanostructures, viz., nanostructures that combine magnetic and plasmonic functionalities [1]. These systems could be the building block of a new class of magnetically controllable optical nanodevices for future biotechnological and optoelectronic applications.

Very recently it was shown how the concerted action of localized plasmon resonances in single nanoparticles and magnetization can be exploited to actively manipulate the reflected light’s polarization (i.e., to induce and control Kerr rotation/ellipticity reversal) of pure ferromagnetic nanostructures beyond what is offered by intrinsic material properties [2], even if plasma oscillations in ferromagnetic materials typically exhibit a stronger damping than in noble metals [3]. While most of the investigations carried out before were focused on the achievement of substantial enhancement of magneto-optical Kerr effect here we study the polarizability of nanoferromagnets to understand

the role of the phase of localized plasmon resonances on their magneto-optical activity. We demonstrate that these systems can be described as two orthogonal damped oscillators coupled by the spin-orbit interaction, as shown in Fig. 1. We prove that only the spin-orbit induced transverse plasmon plays an active role on the magneto-optical properties by controlling the relative amplitude and phase lag between the two oscillators [4]. A formalism to compute the polarizability, as well as the far-field magneto-optical spectra, of large magnetic ellipsoidal nanoelements, i.e., exceeding the Rayleigh limit (electrostatic regime) is presented [5]. This approach can be applied to real samples of optically non-interacting flat disks with circular and elliptical sections, and size up to a few hundred nanometers. We find a surprisingly excellent quantitative agreement between calculated and experimental magneto-optical spectra both for circular and elliptical nanodisks, as shown in Fig. 2. In spite of its approximations and simplicity, the formalism developed captures the essential physics of the interplay between magneto-optical activity and localized plasmon resonances in ferromagnetic nanostructures.


References

[1] G. Armelles et al., Adv. Optical Mater. 1 (2013), 10. [2] V. Bonanni et al., Nano Lett. 11(12) (2011), 5333. [3] J. Chen et al., Small 7(16) (2011), 2341. [4] N. Maccaferri et al., Phys. Rev. Lett 111(16)

(2013), 167401. [5] N. Maccaferri et al., Optics Express 21(8) (2013), 9875.

Figures

Figure 1: A ferromagnetic disk modeled with two orthogonal damped harmonic oscillators coupled by the spin-orbit (SO) interaction; m represents the mass of the conduction electrons; the spring constants kx and ky originate from the electromagnetic restoring forces due to the displacements of the conduction electrons; βx and βy are the damping constants.

Figure 2: Experimental magneto-optical spectra for Ni disks with diameter of 160 nm (a) and elliptical disks with in-plane dimensions of 180 nm and 100 nm. The thickness is 30 nm in both cases. Calculated spectra for circular (b) and elliptical (d) disks. Insets: Scanning Electron Microscopy images of a portion of the samples.


João F. Mano1,2

13B’s Research Group - Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue 2Engineering and Regenerative Medicine, Portugal ICVS/3B’s - PT Government Associate Laboratory, Braga/Guimarães, Portugal

[email protected]

N a n o s t r u c t u r e d p o l y m e r i c m u l t i l a y e r s f o r b i o m e d i c a l

a p p l i c a t i o n s

Appositely charged polyelectrolytes may be assembled into nanostructured multilayered films using the layer-by-layer technology, where the consecutive layers are well stabilized by electrostatic interactions or other weak forces. Using adequate templates, non-flat coatings can be fabricated with tuned compositions along the build-up assembly. This enables the production of very well controlled multifunctional and structural devices using mild processing conditions that could be useful in biomedicine, including in tissue engineering or in drug delivery. In such applications, where there is a direct interaction between the implant with tissues and cells, the biomaterials must exhibit adequate surface characteristics, both at the chemical and topographic points of view. Such systems should also respond adequately to external variables or cellular stimuli. Examples of nano-stratified surfaces with tuned characteristics are presented, using polysaccharides or synthetic biomimetic macromolecules prepared by recombinant biotechnology routes. In particular, methodologies will be discussed to produce: (i) controlled surfaces with stimuli-responsiveness capability (e.g. to temperature or pH) or exhibiting other specific properties (for example, adhesiveness); (ii) Hierarchical organised multifunctional capsules for the controlled delivery of bioactive agents; and (iii) 3-dimensional devices for cell colonisation (e.g. capsules or scaffolds).


Paula A.A.P. Marques, Gil Gonçalves, Sandra Cruz, Nuno Almeida, Patrícia Silva, Susana Pinto, Mercedes Vila NRD -TEMA, Mechanical Engineering Department, University of Aveiro, 3810-193 Aveiro, Portugal

[email protected]

G r a p h e n e o x i d e : a m u l t i f u n c t i o n a l n a n o p l a t f o r m t o b u i l d i n n o v a t i v e m a t e r i a l s

The chemical exfoliation of graphite through oxidative solution methodologies originate stable aqueous suspensions of graphene oxide (GO), [1-3] that can be used as a precursor on the synthesis of graphene by applying chemical or thermal reducing methods. This intermediary specie has attracted the attention of scientists because its surface chemistry is highly versatile. The presence of the oxygen functional groups allows the use of several functionalization approaches [4-9]. This communication aims to give an overview of the work being developed in the Nanotechnology Research Division at TEMA, University of Aveiro, with GO as a multifunctional platform to create innovative materials for wide range of potential applications. First, we were pioneer showing that the presence of oxygen functionalities at the GO surface provides reactive sites for the nucleation and growth of gold and silver nanoparticles [10, 11]. Metallic nanoparticles are effectively grown at GO surfaces using traditional chemical methods in aqueous medium. The nucleation and growth mechanisms depend on the degree of oxygen functionalization at the GO surface (Figure 1). These graphene/gold or silver nanocomposites are being presently explored as substrates for the specific detection of biomolecules by SERS (surface enhanced Raman scattering) studies. The surface modification of these nanocomposites needs to be explored in order to fine-tune their SERS activity and make them specific to identify certain biomolecules. In this way, we aim to contribute to the development of manageable SERS sensors for the selective detection of biomolecules in targeted research. The organochemistry of the GO was also explored. We have successfully modified the surface of GO with polymethylmethacrylate (PMMA) chains (PD = 1.09) via atom transfer radical polymerization

(ATRP) [7]. This strategy can be further exploited to grow a large range of polymers from the GO surface only by changing the monomer. The surface modification of GO with PMMA chains aimed at increasing the compatibility between nano-sheets and polymer matrices as surface characteristics are determinant to yield nanocomposites with improved properties. The resulting nanocomposites were readily dispersed in organic solvents and used as reinforcement fillers in the preparation of PMMA composite films. When GO modified with PMMA was used, a much more homogeneous distribution of the fillers in the PMMA matrix was achieved, contributing to improved mechanical and thermal properties. The addition of 1% (w/w) of GO modified with PMMA fillers clearly led to a significant improvement of the elongation at break, yielding a much more ductile and, therefore, tougher material. Thermal analysis showed an increase in the thermal stability properties of the films prepared with modified fillers in comparison with non-modified GO fillers. Another promising field of research being explored in our group is the use of nano-GO for tumour hyperthermia [12]. GO, has a strong NIR (700-1100 nm range) optical absorption ability and its low-cost production and unique small 2D shape and aspect ratio are incomparable to any other particle. The use of NIR light for the induction of hyperthermia is particularly attractive, because biological systems mostly lack chromophores that absorb in the NIR region. We have recently published a study of cell internalization kinetics and showed that high concentrations of this material cause a dose-dependent oxidative stress in different cell types and a slight loss of their viability. Moreover we have evaluated the type of cell damage produced by this hyperthermia treatment in order to give light to the process and open the door to future understanding


of the application and versatility of these nanovectors. [13-15] Recently, the knowledge to prepare tri-dimensional (3D) structures of reduced GO opened the possibility to explore this material in the field of heterogeneous catalysis (Figure 2). Advantages such as high surface area and absence of mass transfer limitations for substrates that reach the graphene surface sites make 3D graphene structures promising catalysts. Additional advantages of graphenebased materials as catalysts are sustainability and absence of transition metals in their composition. The large surface area of these foams stimulated our interest, therefore we decided to analyse its catalytic ability to oxidize a thioether (thioanisol) in comparison to its 2D counterpart. The preliminary results of this study show a very high efficiency for the degradation of organosulfur compounds at room temperature, opening the way for interesting applications in the environmental field. Undoubtedly, graphene based nanocomposites hold a great potential for being robust functional materials to address various health or environmental related issues. In spite of the remarkably rapid progress, the potential of GO based materials in these fields has yet to be fully explored.

References

[1] WS Hummers Jr., RE Offeman. J. Am. Chem. Soc., 80

(1958) 1339 [2] DC Marcano, DV Kosynkin, JM Berlin, A Sinitskii, Z Sun,

A Slesarev, LB. Alemany, W Lu and JM Tour. ACS Nano, 4 (2010) 4806

[3] J Chen, B Yao, C Li, G Shi. Carbon, 64 (2013) 225 [4] DR Dreyer, S Park, CW Bielawski, RS Ruoff. Chem. Soc.

Rev. 39 (2010) 228 [5] KP Loh, Q Bao, PK Ang, J Yang. J. Mater. Chem. 20

(2010) 2277. [6] N Karousis, SP Economopoulos, E Sarantopoulou, N.

Tagmatarchis. Carbon 48 (2010) 854. [7] G Goncalves, PAAP Marques, AB Timmons, I. Bdkin, MK

Singh, N Emami, J Gracio. J. Mater. Chem. 20 (2010) 9927.

[8] CH Lu, HH Yang, CL Zhu, X Chen, GN Chen. Angew.Chem.-Int. Edit. 48 (2009) 4785.

[9] K Yang, L Feng, X Shi, Z Liu, Chem. Soc. Rev. 42 (2013) 530

[10] G Gonçalves, PAAP Marques, C Granadeiro, HIS Nogueira, MK Singh, J Grácio. Chemistry of Materials, 21 (2009) 4796

[11] MK Singh, E Titus, R Krishna, Gil Goncalves, PAAP Marques, J Gracio. J. Nanos. Nanotech. 12 (2012) 6731

[12] Gonçalves, M Vila, MT Portolés, M Vallet-Regi, J Gracio, PA. A.P. Marques. Advanced Healthcare Materials, 2 (2013) 1072

[13] M Vila, MC Matesanz, M Concepción, G Gonçalves, MJ Feito, J Linares, PAAP Marques, MT Portoles, M Vallet-Regí.Nanotechnology Article reference: NANO-101129.R1

[14] MC Matesanz, MVila, MJ Feito, J Linares, G Gonçalves, M Vallet-Regi, PAAP Marques, MT Portolés. Biomaterials 34 (2013) 1562

[15] M Vila, MT Portolés, PAAP Marques, MJ Feito,MC Matesanz, C Ramírez-Santillán, G Gonçalves, SMA Cruz, A Nieto-Peña, M Vallet-Regi. Nanotechnology 23 (2012) 465103

Figures

Figure 1: Gold/graphene nanocomposites. A) TEM image illustrating the gold nanoparticles distribution at graphene surface. B) Schematic representation of the gold nanoparticles nucleation at the GO surface.

Figure 2: Graphene foams. A) Graphene foam. B) and C) SEM images of the inner structure of the foams.


Adelio Mendes1, Luisa Andrade1

and Anders Bentien2 1LEPABE – Departamento de Engenharia Química, Faculdade de Engenharia da Universidade do Porto, Portugal 2Department of Engineering & iNano, Hangoevej 2, 8200 Aarhus , Denmark

[email protected]

P h o t o e l e c t r o c h e m i c a l c e l l s : f r o m w a t e r s p l i t t i n g t o e l e c t r o c h e m i c a l e n e r g y

s t o r a g e

Electricity produced from solar and wind energy sources have limited or no dispatchability, making storage of energy a hot research topic. Pumped-storage hydroelectricity has several advantages, namely high capacity, reasonable response time, high cycle efficiency and low costs. However, for countries of limited hydraulic energy resources and for local storage, other approaches should be considered. Redox flow batteries (RFB) store energy in electrolyte solutions upon anodic and cathodic reversible redox reactions, as sketched in Figure 1. Storage capacity and power are independent variables in RFB, which are suitable for stationary applications due to the low storage costs, high cycle efficiency and low energy storage density. The implementation of directive (2010/31/EU) concerning “nearly zero-energy buildings” will require the storage of energy in buildings. Though, RFB can be used with advantages for this objective, it would be great if they can be directly charged

from solar radiation besides other energy sources such as urban wind power or BIPV. Very recent results by the authors show that not only this is possible but thermodynamic energy conversion efficiencies up to 40 % are possible. This work deals about this new development that requires the use of photoelectrochemical cells – Figure 2.

References

[1] Weber, A., Mench, M., Meyers, J., Ross, P.,

Gostick, J., Liu, Q., “Redox flow batteries: a review”, J. Appl. Electrochem., DOI 10.1007/s10800-011-0348-2, 2011.

Figures

Figure 1: Sketch of a redox flow battery (extracted from [1]).º Figure 2: Photoelectrochemical cell “PortoCell”


Jean-Louis Mergny1,2

1Univ. Bordeaux, ARNA laboratory, Bordeaux, France 2INSERM U869, IECB, F-33600 Pessac, France

[email protected]

U n u s u a l N u c l e i c A c i d s f o r D N A - b a s e d n a n o d e v i c e s

Nucleic acids are finding applications in nanotechnology as nanomaterials, mechanical devices, templates, logic gates and biosensors. G-

quadruplex DNA, formed by (-( stacking of guanine (G) quartets (Figure 1), is an attractive alternative to regular B-DNA because of the kinetic and thermodynamic stability of quadruplexes [1]. However, they suffer from a fatal flaw: the rules of recognition, i.e. the formation of a G-quartet in which four identical bases are paired, prevent the controlled assembly between different strands leading to complex mixtures. In this report, I will present different solutions to this recognition problem. The proposed design combines two DNA elements: duplexes and a quadruplex core [2]. Duplexes direct controlled assembly of the quadruplex core, and their strands present convenient points of attachments for potential modifiers or DNA origamis [3]. The exceptional stability of the quadruplex core provides integrity to the entire structure which could be used as a building block for nucleic acid-based nanomaterials. Our findings pave the way to broader utilization of G-quadruplex DNA in structural DNA nanomaterials and nanodevices.

Acknowledgments: This work was supported by INSERM, University of Bordeaux, Agence Nationale de la Recherche (ANR grants G4-Toolbox & QuantADN), and Région Aquitaine grants.

References

[1] P. L. Tran, A. De Cian, J. Gros, R. Moriyama, J. L.

Mergny, Topics in current chemistry 2013, 330, 243-273.

[2] a) L. A. Yatsunyk, O. Pietrement, D. Albrecht, P. L. Tran, D. Renciuk, H. Sugiyama, J. M. Arbona, J. P. Aime, J. L. Mergny, ACS nano 2013, 7, 5701-5710; b) J. Zhou, A. Bourdoncle, F. Rosu, V. Gabelica, J. L. Mergny, Angewandte Chemie 2012, 51, 11002-11005.

[3] A. Rajendran, M. Endo, K. Hidaka, P. Lan Thao Tran, J. L. Mergny, H. Sugiyama, Nucleic acids research 2013, 41, 8738-8747.

Figures

Figure 1: Presentation of a G-quartet with four coplanar guanines.


Javier Molina1,2, Javier Fernández1, Ana

I. del Río1, J. Bonastre1, F. Cases1 1Departamento de Ingeniería Textil y Papelera (DITEXPA), Universitat Politècnica de València, Spain 2Department of Textile Engineering, University of Minho, Portugal

[email protected]

C h e m i c a l d e p o s i t i o n o f r e d u c e d g r a p h e n e o x i d e o n

f a b r i c s

Reduced graphene oxide (RGO) has been deposited on polyester (PES) fabrics to produce conductive textiles [1, 2]. In the first stage, PES is put in contact with the graphene oxide (GO) solution; adsorption of GO sheets takes place on the surface of the fabric. In the second stage GO is reduced to RGO by means of Na2S2O4 chemical reduction. Different number of RGO coatings (1-4) was applied to the fabrics and characterized (PES-1G, PES-2G, PES 3G and PES-4G). Fig. 1 shows the SEM micrographs of PES coated with 1 RGO layer, RGO sheets can be distinguished on the surface of the fibers. The conducting textiles obtained have been characterized electrically by means of electrochemical impedance spectroscopy (EIS). The results have shown a decrease of the resistance of more than six orders of magnitude when GO was converted to RGO (from >1011

to 2.6·104 Ω·cm2) (single coating) (Fig. 2). This decrease can be correlated to the partial restoration of the sp2 graphitic structure when GO is reduced to RGO as X-ray photoelectron spectroscopy (XPS) results have shown. With more RGO layers applied, the resistance decrease reached 9 orders of magnitude for 3 layers (23 Ω·cm2). The phase angle also changed from 90º (insulating behaviour) for PES and PES-GO to 0º for RGO coated samples (conducting behaviour). Electrochemical activity of the coatings was measured by means of cyclic voltammetry (CV) and scanning electrochemical microscopy (SECM). CV of the fabrics has shown that scan rate is a key parameter in the characterization of these materials; only low scan rates allow the proper observation of redox processes. In addition, it is necessary to compensate the ohmic loss of the fabric. Results showed that electroactivity increased with the number of RGO coatings. SECM measurements were performed in the approach mode to test the electroactivity of the fabrics. Two different redox mediators were employed: Ru(NH3)6

3+/2+ and Fe(CN)6

3−/4−, obtaining best results with the second one. The explanation for this is that Fe(CN)6

3−/4− is sensitive to the state of carbon surface. On the other hand Ru(NH3)6

3+/2+ represents the simplest case of an outer-sphere electron transfer with no known chemical interactions with the surface. A clear electroactivity

change was observed when GO was reduced to RGO; the behaviour passed from negative feedback for PES-GO (insulating material) to positive feedback (conducting material) (Fig. 3). In this case, the values of positive feedback also changed with the number of RGO coatings, from 1.1 for one RGO coating to 1.6-1.7 for 2-4 coatings (Fig. 3). It should be taken into account that SECM is a local technique and the sample is not biased, in this case only the degree of coverage plays a role in the electrochemical activity. With 2-4 coatings the sample is completely coated and no differences of electroactivity can be discerned by SECM (in this case the better contact between the different RGO sheets for more RGO coatings does not play a role since sample is not biased). By means of CV and EIS, these differences could be appreciated since a higher number of coatings allowed a better contact between the different RGO sheets and consequently a better conductivity was observed. The results obtained by means of SECM also showed that the fabrics could also act at open circuit potential as an oxidant or a reductant with equal heterogeneous transfer electron charge transfer kinetics in both cases.

Acknowledgements: Authors wish to thank to the Spanish Ministerio de Ciencia e Innovación (contract CTM2011-23583) for the financial support. J. Molina is grateful to the Conselleria d’Educació, Formació i Ocupació (Generalitat Valenciana) for the Programa VALi+D Postdoctoral Fellowship. A.I. del Río is grateful to the Spanish Ministerio de Ciencia y Tecnología for the FPI fellowship. References

[1] J. Molina, J. Fernández, J.C. Inés, A.I. del Río, J.

Bonastre, F. Cases, Electrochimica Acta 93 (2013) 44.

[2] J. Molina, J. Fernández, A.I. del Río, J. Bonastre, F. Cases, Applied Surface Science 279 (2013) 44.

[3] R.L. McCreery, Chemical Reviews 108 (2008) 2646.


Figures

Figure 1: Micrographs of PES-1G samples (polyester coated with one RGO coating).

Figure 2: Bode plots for PES, PES-GO, PES-1G, PES-2G, PES-3G and PES-4G samples. Sample located between two copper electrodes. Frequency range from 105 Hz to 10−2 Hz.

Figure 3: Approaching curves for: a) PES-GO (___) and theoretical negative feedback model (). b) PES-1G, PES-2G, PES-3G and PES-4G samples. Theoretical positive feedback model is also presented for comparison (Δ). Obtained with a 100 μm diameter Pt tip in 0.01 M Fe(CN)6

3- and 0.1 M KCl. The tip potential was 0 mV (vs Ag/AgCl) and the approach rate was 10 μm·s-1.


Simgeon Oh and Dae Joon Kang* BK21Plus Physics Research Division, Department of Energy Science, Institute of Basic Science, SKKU Advanced Institute of Nanotechnology, Sungkyunkwan University, Korea

*[email protected]

N o v e l S y n t h e t i c R o u t e s f o r U l t r a - l o n g Z n O M i c r o w i r e s

w i t h C r o s s - s e c t i o n a l S h a p e M o d u l a t i o n

We have successfully developed a novel synthetic route for growing ultra-long ZnO microwires (MWs) by using thermal chemical vapor deposition method. High quality ZnO MWs having the diameter of 3-10 μm and the length of up to 2 cm were easily obtained at ultrafast growth speed by exploiting the

novel catalytic effects of III-Ⅴ semiconductors. Various unique cross-sectional shapes were also obtained by carefully tuning the growth parameters based on thermodynamics. It is found that III-V semiconductor catalyst plays a critical role in obtaining high quality ZnO MWs with cross-sectional shape modulation. We observed that the cross-sectional shape of MWs can be easily modulated by careful tuning of the ramping time and the growth temperature with a help of III-V semiconductor catalyst, which produces lozenge, triangular, asymmetric hexagonal or symmetric hexagonal shapes. We proposed a growth mechanism and

attempted to understand how the III-V semiconductor catalyst plays a role in the growth of ZnO MWs. Such ultra-long ZnO MWs with different cross-sectional shapes are of importance for both understanding the fundamental material physics and integrating these structures into optoelectronic and power electronic devices such as self-power generators, touchable sensor and high energy blue laser LEDs.

References

[1] Zhiyong Fan, Jia G. Lu, Journal of Nanoscience and Nanotechnology, 5(10) (2005) 1561-1573.

[2] Jun Wang, Jian Sha, Qing Yang, Xiangyang Ma, Hui Zhang, Jun Yu, Deren Yang, Materials Letters, 59(21) (2005) 2710-2714.

Figures

Figure 1: Vertically grown ZnO MWs at 990 ºC on a-cut sapphire substrate.

Figure 2: Cross-sectional shape modulation of ZnO MWs.


Isabel Pastoriza-Santos,a Sergio Gómez-

Graña,a Bart Goris,b Thomas Atlantis,b Cristina Fernández-López,a Enrique Carbó-Argibay,a Andres Guerrero-Martínez,a,c Neyvis Almora-Barrios,d Nuria López,d Jorge Pérez-Juste,a Sara Balsb and Luis M. Liz-Marzána,e,f aDep de Química Física, Universidade de Vigo, Spain bEMAT-University of Antwerp, Belgium cDepartment of Physical Chemistry I, UCM, Spain dInstitute of Chemical Research of Catalonia, Spain eBionanoplasmonics Laboratory, CIC biomaGUNE, Spain f Ikerbasque, Basque Foundation for Science, Spain

[email protected]

H a l i d e s D i r e c t e d g r o w t h o f A u @ A g N a n o p a r t i c l e s

Seed-mediated growth is the most efficient methodology to control the size and shape of colloidal metal nanoparticles. In this process, the final nanocrystal shape is defined by the crystalline structure of the initial seed as well as by the presence of ligands and other additives that help to stabilize certain crystallographic facets. We analyze here the growth mechanism in aqueous solution of silver shells on pre-synthesized gold nanoparticles displaying various well-defined crystalline structures and morphologies (Figure 1) [1]. A thorough three-dimensional electron microscopy characterization of the morphology and internal structure of the resulting core-shell nanocrystals indicates that,

under our reduction conditions, 100 facets are preferred for the outer silver shell, regardless of the morphology and crystallinity of the gold cores (Figure 1). These results are in agreement with theoretical analysis based on the relative surface energies of the exposed facets in the presence of halide ions. References

[1] Sergio Gómez-Graña, et al., Journal, 4 (2013)

2209–2216.

Figures

Figure 1: Representative TEM images of the different gold nanoparticles used as seeds and representative dark field TEM images of the core-shell particles where the preferential deposition of silver can be easily elucidated (right column).


Pedro M. R. Paulo1, Peter Zijlstra2 and

Michel Orrit3 1Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Portugal 2Molecular Biosensors for Medical Diagnostics, Eindhoven University of Technology, The Netherlands 3MoNOS, Huygens Laboratorium, Universiteit Leiden, The Netherlands

[email protected]

T i p - S p e c i f i c F u n c t i o n a l i z a t i o n o f G o l d N a n o r o d s f o r P l a s m o n i c B i o s e n s i n g

Plasmonic biosensors based on functionalized metal nanoparticles are being investigated for the many possibilities opened up by using a nano-object as a label-free sensor.[1] For instance, they give access to miniaturization and multiplexing of devices or to biosensing inside live cells. Also, the nanometric volume probed by a single metal nanoparticle is ideal for detection at single-molecule level.[2,3] The probed volume is defined by the region of enhanced electric field surrounding the plasmonic particle. For metal nanorods, this enhancement is strongly concentrated at the tips (Figure 1A). The adsorption of a biomacromolecule at the tips is transduced into a larger frequency shift of the surface plasmon resonance making easier its optical detection. Tip-specific functionalization gives practically the same sensor response as full-surface functionalization and it avoids undesirable line broadening by chemical interface damping.[4] For single-molecule detection, the better sensitivity from specifically functionalizing the tips makes it possible to detect every single molecule that binds and unbinds to the nanorod.[2] In ensemble conditions, it is also advantageous as it maximizes the plasmon shift by concentrating all the analyte in the region with the highest field.

We have developed a chemical procedure for tip-specific functionalization of gold nanorods. This procedure was used to attach biotin receptors to nanorods with ensemble-average dimensions of 9 nm by 37 nm, and a longitudinal plasmon in water at approximately 760 nm. The functionalized gold nanorods were used as a proof-of-concept for plasmonic biosensing of streptavidin (Figure 1B). The red-shift of the plasmon peak was followed over time to trace the binding kinetics of streptavidin-biotin at the nanorods’ surface (Figure 1C). The response to increasing streptavidin concentrations afforded its binding affinity (Figure 1D). We find dissociation

constants (Kd) in the range of nM that are around five orders of magnitude higher than in solution. Similarly high values of Kd have been reported in the literature with some degree of dependency on the biotin-linker length and its surface density. We have also explored different biotin-linker lengths (13.5, 29 and 56 Angström) and compared assays on nanorods that were fully functionalized with biotin or specifically at the tip. The longer linker in combination with a sparse tip-functionalization yielded the largest plasmon shift, ca. 10 nm, at surface saturation. This result suggests that steric hindrance is most likely interfering with binding affinity of streptavidin-biotin at the surface. The binding kinetics seem to also support this picture by showing strong deviations from first order exponential kinetics, although other effects may also interfere e.g., non-specific adsorption. In this contribution, we will discuss these effects to elucidate the role of surface chemistry in the design and performance of plasmonic biosensors.

References

[1] K. M. Mayer, J. H. Hafner, Localized surface plasmon resonance sensors. Chem. Rev. 111 (2011) 3828–3857.

[2] P. Zijlstra, P. M. R. Paulo, M. Orrit, Optical detection of single non-absorbing molecules using the surface plasmon resonance of a gold nanorod. Nat. Nanotechnol. 7 (2012) 379–382.

[3] I. Ament, J. Prasad, A. Henkel, S. Schmachtel, C. Sönnichsen, Single Unlabeled Protein Detection on Individual Plasmonic Nanoparticles. Nano Lett. 12 (2012) 1092−1095.

[4] P. Zijlstra, P. M. R. Paulo, K. Yu, Q. H. Xu, M. Orrit, Chemical Interface Damping in Single Gold Nanorods and Its Near Elimination by Tip-Specific Functionalization. Angew. Chem. Int. Ed. Engl. 51 (2012) 8352–8355.


Figures

Figure 1: (A) Near field enhancement calculated with discrete dipole approximation for a gold nanorod of size 31 nm × 9 nm at its longitudinal surface plasmon resonance – white bar corresponds to 10 nm and color scale spans squared field amplitudes from 1 (blue) to 3000 (red); (B) Scheme depicting tip-specific functionalization of a gold nanorod with biotin and binding of streptavidin protein; (C) Kinetic traces of tip-functionalized gold nanorods upon adding a solution of streptavidin 100 nM in PBS buffer – biotin-linker lengths of 13.5 Å (red), 29 Å (green) and 56 Å (blue); (D) Dose-response curve of tip-functionalized gold nanorods with a biotin-linker length of 13.5 Å for streptavidin binding in PBS buffer.


Krasimira T. Petrova REQUIMTE, CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Portugal

[email protected]

S y n t h e s i s o f H y d r o p h o b i c P o l y m e r i c S u c r o s e - C o n t a i n i n g

N a n o p a r t i c l e s

Several bifunctional monomers have been synthesized from the key intermediate 1’,2,3,3’,4,4’-hexa-O-benzylsucrose under microwave irradiation, which allowed significant reduction of time and energy for the synthetic procedures. These monomers were co-polymerized with styrene to obtain cross-linked hydrophobic, sucrose-containing co-polymers. Formation of nano-sized hydrophobic particles was achieved by dispersion polymerization in aqueous media. The resulted polymeric nanoparticles have been characterized by the polymers constitution, degree of cross-linking, glass-transition temperature (Tg), measured by Differential Scanning Calorimetry (DSC), and particles form and size by Atomic Force Microscopy (AFM). Acknowledgments: This work has been supported by Fundação para a Ciência e a Tecnologia through Grant No. PEst-C/EQB/LA0006/2013 and PTDC/SAU-BMA/122444/2010. The presenting author is grateful to Prof. J. Caldeira and AFM lab at REQUIMTE, and to the co-authors Prof. M.Teresa Barros and M.Sc. Cláudia Raposo.

References

[1] Barros, M. T.; Petrova, K.; Ramos, A. M. J. Org.

Chem., 69 (2004) 7772. [2] Crucho, C. C.; Petrova, K. T.; Pinto, R. C.; Barros,

M. T. Molecules, 13 (2008) 762. [3] Barros, M. T.; Petrova, K. T. Eur. Polym. J., 45

(2009) 295–301. [4] Barros, M. T.; Petrova, K. T.; Singh, R. P. Eur.

Polym. J., 46 (2010) 1151. [5] Barros, M. T.; Petrova, K. T.; Correia-da-Silva, P.;

Potewar, T. M. Green Chem., 13 (2011) 1897. [6] Peça, I. N.; Petrova, K. T.; Cardoso, M. M.;

Barros, M. T. React. Funct. Polym., 72 (2012) 729.

[7] Barros, M. T.; Petrova, K. T.; Correia-da-Silva, P.; Esteves, A. P. In Carbohydrate Chemistry: Proven Synthetic Methods; van-der-Marel, G., Codee, J., Eds.; CRC Press: Taylor & Francis Group, 2014; Vol. 2, Chapter 14, p 103.

+AIBN

= sucrose moiety styreneSucrose-containingpolymeric nanoparticle

n m


A.P. Piedade1, J.Nunes1, P.V.Morais2,

C.B.Duarte2,3 1CEMUC – Department of Mechanical Engineering, Polo II, University of Coimbra, Coimbra, Portugal 2Department of Life Sciences, University of Coimbra, Coimbra, Portugal 3CNC Center Neurosciences & Cell Biology, University of Coimbra, Portugal

[email protected]

N e u r a l i m p l a n t s n a n o c o m p o s i t e c o a t i n g s w i t h a n t i b a c t e r i a l a c t i o n t o w a r d s

n o s o c o m i a l p a t h o g e n s

The use of biomaterials in the neuroscience field comprises the monitoring of intracranial pressure, matrix for drug release and probes of the neural system. The latest includes devices for the increase or decrease of a specific neurologic function[1]. One of the most described devices is the use of implants to reduce or even cancel the involuntary spontaneous movements that characterize Parkinson's disease[2]. Many of the obstacles in this area of biomedicine is the lack of compatibility of materials with the biological system. In fact, the material usually used in neural implants processing is silicon (inheritance of the microelectronics industry), although other materials emerge as potential candidates [3,4]. The corrosion problems associated with their implantation in a biological environment has been corrected by the modification of the surface with biomolecules [5], conductive polymers [6,7], metal alloy films [4,8] or silicone-based gels [3]. Currently, it is believed that the mechanism of instability and degradation of implanted materials is due to their "encapsulation" by reactive astrocytes that isolate the implant and induce the increase of the distance between adjacent neurons, inhibiting synapsis [9]. Moreover, the decrease in the density of neurons has also been recently associated with an adverse reaction to the implantation of systems based on silicon [10]. In this work we have developed hybrid nanocomposite thin films based on silica (SiO2) in order to improve the biological performance of Si neural implants. The aim also included the ability of the modified surfaces to present antibacterial action against common pathogens associated with nosocomial infections. The use of silica allows a chemical compatibility with the underlying Si substrate thus allowing that substrate and coating

form a continuum instead of the sum of two different materials which can induce stresses at the interface. The nanocomposite was obtained by doping the SiO2 with silver (Ag) and gold (Au) (Figure 1). The introduction of silver is related to is known antibacterial properties and the presence of Au allows serving two purposes: ensuring the electric conductivity of the coating after silver release as well as an enhancer of cells adhesion and spreading as described in the literature[11]. The antimicrobial activity was assessed by determining the growth inhibition on Gram-negative (Acinetobacter lwoffii and Pseudomonas aeruginosa) and Gram-positive (Enterococcus faecalis) bacterial strains. The results highlight that SiO2/Ag/Au nanocomposite thin films present good antibacterial activity against the three studied microorganisms (Figure 2). The preliminary results of in vitro cell tests also indicate that these coatings present better biological performance regarding neural cell proliferation and viability than bare Si substrates (Figure 3). References

[1] Seymour J.P.; Kipke D.R., Biomaterials, 28 (2007) 3594–

3607 [2] Leopold N.A.; Polansky M.; Hurka M.R., Movement

Disorders , 19 (2004) 513-517. [3] Polikov V.S.; Tresco P.A.; Reichert W.M., J Neurosci

Methods, 148 (2005) 1-18. [4] Gimsa J.; Habel B.; Schreiber U.; Rienen U. V.; Strauss

U.; Gimsa U., Journal of Neuroscience Methods, 142 (2005) 251–265.

[5] Azemi E.; Stauffer W.R.; Gostock M.S.; Lagenaur C.F.; Cui X.T., Acta Biomaterialia, 4 (2008) 1208–1217.

[6] Richardson-Burns S- M.; Hendricks J.L.; Foster B.; Povlich L.K.; Kim D.H.; Martin D.C., Biomaterials, 28 (2007)1539–1552.


[7] Green R.A.; Lovell N.H.; Wallace G.G., Biomaterials 29 (2008) 3393–3399.

[8] Harnack D.; Winter C.; Meissner W.; Reum T.; Kupsch A.; Morgenstern R., Journal of Neuroscience Methods 138 (2004) 207–216.

[9] Szarowski D.H.; Andersen M.D.; Retterer S.; Spence A.J.; Isaacson M.; Craighead H.G.; Turner J.N.; Shain W., Brain Res, 983 (2003) 23-35.

[10] Biran R.; Martin D.C.; Tresco P.A., Exp Neurol, 195 (2005)115–126.

[11] Bouafsoun A.; Helali S.; Othmane A.; Kerkeni A.; Prigent A.F.; Jaffrezic-Renault N.; Bessueille F.; Leonard D.; Ponsonnet L., Macromol. Biosci. 7 (2007) 599–610.

Figures

Figure 1: TEM bright field micrograph of a nanocomposite hybrid SiO2/Ag/Au thin film.

Figure 2: Growth inhibition test of nanocomposite hybrid SiO2/Ag/Au thin film with A.lwoffii (a) P. aeruginosa (b) and E. faecalis (c)

Figure 3: SEM micrographs of the surface of control (a), SiO2/Ag/Au thin film (b) and Si (c) after 14 days with cortex rat embryo cells culture.


Vera V. Pintoa, Maria José Ferreiraa,

Joana Gomesa, Virgínia M. Teixeiraa,b, Paula M. V. Fernandesb, Ana C. Nevesb, Flávia M. Teixeirab, Joana S. Mendesb, Carlos M. Pereirab aCTCP, Portugal bCentro de Investigação em Química UP- L4, Portugal

[email protected]

F o o t w e a r I n d u s t r y : U s e o f n a n o p a r t i c l e s i n t h e

d e v e l o p m e n t o f m a t e r i a l s w i t h a n t i m i c r o b i a l p r o p e r t i e s

Footwear industry is recognized by its innovative capability in the development of added value fashion and comfortable leather shoes. Presently, consumers expectations and needs require the development of footwear that integrates fashion, emotional desires and real multifunctional performance. Consumers are becoming more enlightened and demanding, searching for differentiated products which promote their comfort, health and welfare is significantly increasing. To keep competitiveness, the footwear companies need to put their efforts in the development of differentiated and advanced products to meet the needs of the actual market. In this way footwear sector has been investing in the development of new and functional materials namely with antimicrobial properties. The control of bacteria and fungus growth is important to prevent and minimize the generation of malodors and some foot skin problems. The footwear industry has been exploring the benefits of remarkable properties of nanoparticles on the development of new products with high performance. This route was initiated at CTCP in collaboration with FCUP with a more fundamental study to prepare stable Ag NPs with antimicrobial properties. Ag NPs antimicrobial properties were confirmed against E.

coli, S. epidermis and B. subtilis (figure 1). Ag NPS were also used on leather surface modifications to confer antimicrobial properties [1-3]. Cu, CuO and ZnO nanoparticles were also studied as alternatives to Ag NPs. Cu, CuO and ZnO NPs were prepared using different methods allowing to obtain NPs with different shapes, sizes and properties [4-15]. Furthermore the nanoparticles were characterized by TEM/SEM images and UV-Vis and their stability and antimicrobial properties were accessed. The antimicrobial properties were tested

against E. coli and S. epidermis using methods developed by CTCP. Although Cu NPs (figure 2) revealed good antimicrobial properties their low stability render them difficult to be used in industrial applications. By contrast ZnO showed good stability and also displayed antimicrobial properties. Different procedures were used to prepare reproductively spherical ZnO nanoparticles (figure 3) and the following step is scale-up the use of nanoparticles to develop advanced and innovative nanotechnology based solutions for leathers and polymers components for footwear products, aiming a new sustainable and customer-driven production of consumer goods; where the health, environment, high quality of components, fair marketing communication and competitive sales price are combined to promote the competitiveness of the companies. References

[1] V. V. Pinto, M. J. Ferreira, R. Silva, H. A. Santos, C. M. Pereira, Colloids and Surfaces A: Physicochem. Eng. Aspects, 364 (2010) 19.

[2] V.V. Pinto, M.J. Ferreira, R.M. Silva, C.M. Pereira, The nanoscience in footwear technology, UITIC – International Association of Shoe Technicians, 32º Congreso Internacional sobre Tecnologia en la Industria del Calzado: El poder de las ideas en el mercado del calzado, 8-9 October, Léon México (2010).

[3] V.V. Pinto, M.J. Ferreira, C.M. Pereira, “Nanoparticles applied on footwear: silver nanoparticles applied on the leather modification for antimicrobial properties, E2N 2011- National Meeting of Nanotoxicology, Lisbon (2011).


[4] X. Ren, D. Chen, F. Tang, J. Phys. Chem B 109 (2005) 15803.

[5] N.R. Jana, Z.L. Wang, T.K. Sal, T. Pal, Current Science, 79 (2000) 1367.

[6] C. Wu , B.P. Mosher, T. Zheng, J. Nanopart. Res., 8 (2006) 965.

[7] J. Zhu, D. Li, H. Chen, X. Yang, L. Lu, X. Wang, Materials Letters, 58 (2004) 3324.

[8] Wu,S-H. ; Chen, D-H.; Journal of Colloid and Interface Science, 273 (2004) 165.

[9] H. Meruvu, M. Vangalapati, S.C. Chippada, S.R. Bammidi, Rasayan J.Chem., 4 ( 2011) 217.

[10] M. Sudha, M. Rajarajan, IOSR Journal of Applied Chemistry, 3 (2013) 45.

[11] M. Sudha, S. Senthilkumar, R. Hariharan, A. Suganthi, M. Rajarajan, Journal of Sol-Gel Science and Technology, 65 (2013) 301.

[12] B.F. Dejene, H.C. Swart, M.A. Tshabalala, Physica B, 407 (2012) 1668.

[13] D. Jézéquel, J. Guenot, N. Jouini, F. Fiévet J. Mat. Res., 1 (1995) 77.

[14] H. Karami, E. Fakoori, J. Nanomaterial (2011) ID 628203.

[15] Y. Wang, E. Laborda, C. Salter, A. Crossley, R.G. Compton, Analyst, 137 (2012) 4693.

Figures

Figure 1: Results of antimicrobialtest of unmodified leather (a) and leather modified with Ag NPs (b)

Figure 2: TEM image (a) and absorption spectra (b) of Cu NPs prepared with NaBH and CuCl2

Figure 3: Zinc oxide nanoparticles in suspension and in solid (a) and TEM image (b)


Sophie L. Pirard, Dominique Toye, Jean-Paul Pirard Laboratoire de Génie Chimique, B6a, Université de Liège, B-4000 Liège, Belgium

[email protected]

I n f l u e n c e o f h e a t e x c h a n g e s a n d o f t e m p e r a t u r e p r o f i l e f o r

c a r b o n n a n o t u b e s y n t h e s i s i n a c o n t i n u o u s r o t a r y r e a c t o r

The influence of the reaction exothermicity has been taken into account for the modeling of a continuous inclined mobile-bed rotating reactor for carbon nanotube synthesis by the CCVD method using ethylene as carbon source. The modeling of the continuous reactor was performed according to the reaction chemical engineering approach which consists in studying the four factors governing the reactor, i.e. geometric, hydrodynamic, physical and physico-chemical factors [1]. So the reactor equations have been written by applying the co-current plug-flow hypothesis and by taking the true kinetic equation and the sigmoid catalytic deactivation into account [2]. The four reactor equations correspond to the three mass balances and to the heat balance.

The optimal temperature to maximize the productivity and to avoid the formation of soot and tars is equal to 700°C with ethylene [3, 4]. In small scale reactors, the heat exchange between the carbon nanotube growing bed and the atmosphere of the furnace surrounding the reactor is efficient enough to evacuate the heat released by the reaction and to keep the temperature constant along the reactor. However, for higher production capacity reactors, the global heat released by reaction increases, and the heat exchange has to be efficient enough to evacuate the heat released by the reaction. Otherwise, one may observe a runaway phenomenon. So the heat released by reaction influences the temperature profile through the reactor and heat exchanges have to be taken into account to model the axial temperature profile.

The model has been validated with data obtained on two industrial reactors equipped with heating systems belonging several distinct heating zones with the same length providing an adequate control of the temperature in the reactor. To avoid a too high reaction speed, possibly leading to excessive heat release and to hot point responsible of cracking of ethylene and of reactor fouling by tars and soot deposition in the first reactor sections, the feed temperature of the reacting gas has to be fixed at a value lower or equal to 650°C. Indeed, Fig. 1 highlights the temperature profiles for initial temperatures equal to 650°C and 700°C for a

given experimental set. When the initial gas temperature is equal to 700°C, the heat release leads to a significant temperature increase beyond 700°C, leading to a great deposition of soot and tars. Fig. 1 shows the corresponding temperature profile, which is continuously increasing and tends towards an adiabatic profile.

Furthermore, the model shows that the temperature profile along the reactor has to be as close as possible of the temperature profile of an isothermal reactor at 700°C (Fig.2). This temperature profile can be reached with several heating zones (at least four heating zones) and with an initial temperature at the inlet of the reactor smaller than 700°C due to the exothermicity of the reaction. This result is in agreement with experimental data obtained with the two industrial reactors.

Several articles in the literature show that the fluidized-bed reactor works correctly and produce CNT of good quality [5-7]. According to some references, the fluidized-bed reactor is the only one able to produce CNTs continuously in a large-scale and has already been adopted worldwide for the commercial production of CNTs, because compared with moving-bed reactor, the fluidized-bed reactor has excellent heat and mass transfer properties and good mixing behavior. However, the residence time of each catalyst particle is not constant in a fluidized-bed reactor, leading to an inhomogeneous quality of produced CNTs. The present article shows that by imposing an adequate temperature at the inlet of the reactor and by controlling the temperature of the heating zones in order to regulate heat exchanges between the CNT growing bed and the atmosphere of the heating zones through the reactor wall, the temperature profile along an industrial continuous mobile-bed reactor is almost isotherm and this kind of reactor is very well adapted to continuously produce CNTs of homogeneous quality at a large-scale.


References

[1] J. Villermeaux, Génie de la réaction chimique –

Conception et fonctionnement des réacteurs, Lavoisier (1993) Paris.

[2] S.L. Pirard, C. Bossuot, J.P. Pirard, AIChE J. 55 (2009) 675–686.

[3] S.L. Pirard, S. Douven, C. Bossuot, G. Heyen, J.P. Pirard, Carbon 45 (2007) 1167-1175.

[4] S.L. Pirard, S. Douven, J.P. Pirard, Carbon 45 (2007) 3050–3052.

[5] A.M. Thayer, Chem. Eng. News 85 (2007) 29–35. [6] Q. Zhang, J.Q. Huang, M.Q. Zhao, W.Z. Qian, F.

Wei, Chem. Sust. Chem. 4 (2011) 864–889. [7] R. Philippe, P. Serp, P. KalckP, Y. Kihn, S.

Bordère, D. Plee, P. Gaillard, D. Bernard, B. Caussat, AIChE J. 55 (2009) 450–464.

Figures

Figure 1: Modeled temperature profiles in a reactor with four heating zones for a given experimental set: (1) for an initial temperature equal to 650°C; (2) for an initial temperature equal to 700°C).

Figure 2: Modeled profiles for a given experimental set: (a) specific productivity and (b) temperature (1) profiles for an isothermal reactor at 650°C; (2) profiles for an isothermal reactor at 700°C; (3) profiles for an adiabatic reactor and (4) profiles for a reactor with heat exchanges (four heating zones with the same length).


José A. Pomposo1,2,3

1Centro de Física de Materiales (CSIC, UPV/EHU)-Materials Physics Center, Spain 2Departamento de Física de Materiales, Universidad del País Vasco (UPV/EHU), Spain 3IKERBASQUE - Basque Foundation for Science, Spain

[email protected]

S i n g l e - C h a i n S o f t N a n o p a r t i c l e s a s B i o i n s p i r e d

N a n o m a t e r i a l s

Linear polymer chains can be folded / collapsed to individual, single-chain nanoparticles (SCNPs) by means of different intra-chain cross-linking techniques [1] (Figure 1). SCNP formation is reminiscent of protein folding although current synthetic methods lack the perfection of protein folding to functional enzymes [2]. In recent years the structure−funcon paradigm (i.e., amino acid sequence → 3D structure → funcon) has been revisited by taking into account that many non-structured segments of proteins, and even totally disordered proteins, play important roles in protein function [3]. In this Keynote lecture we highlight the significant added value (enzymatic catalysis, drug binding/delivery) that can be endowed to SCNPs by taking inspiration from the functions of both ordered and disordered proteins [4].

References

[1] A. Sanchez-Sanchez, I, Perez-Baena, J. A.

Pomposo, Molecules 18 (2013) 3339. [2] O. Altintas, C. Barner-Kowollik, Macromol.

Rapid Commun. 33 (2012) 958. [3] P. Tompa, K. H. Han, Phys. Today 65 (2012) 64. [4] J. A. Pomposo, Polym. Int. 63 (2014) DOI:

10.1002/pi.4671.

Figures

Figure 1: Illustration of hard (a) and soft (b) synthetic nano-objects. Biomimetic SCNPs can be constructed by taking inspiration from the functions of soft, natural nano-objects (c) and, in particular, from both folded proteins and intrinsically disordered proteins [4].


Sohel Rana, Shama Parveen, Raul Fangueiro, M. C. Paiva University of Minho, Campus de Azurem, 4800-058 Guimaraes, Portugal

[email protected]

A q u e o u s d i s p e r s i o n o f v a r i o u s t y p e s o f c a r b o n n a n o t u b e s a t

h i g h c o n c e n t r a t i o n s u s i n g P l u r o n i c F 1 2 7

Carbon nanotubes (CNTs) are finding widespread applications in various fields including catalyst supports, optical devices, quantum computers, and biomedical field due to their unique electronic, thermal, optical, and mechanical properties [1, 2]. Most of these applications require stable suspensions of high concentration of CNTs. The non-covalent functionalization technique of producing CNT suspensions is better in the sense that it does not alter the inherent electrical, optical or mechanical properties of CNT. In this route, CNTs are commonly dispersed using various surfactants, such as etyltrimethylammonium bromide, Triton X-100, sodium dodecylbenzene sulfonate (SDBS), Pluronic F127, etc. [3], with the help of ultrasonication process, which breaks down or de-bundles the CNT aggregates. The treatment time or energy of the ultrasonication process has strong influence on CNT dispersion and within limits, longer is the treatment time (and higher is the ultrasonication energy), better is the CNT dispersion. However, a longer ultrasonication treatment or higher ultrasonication energy may also reduce the aspect ratio and lead to CNT damage. From this point of view, a short and mild dispersion process is always favourable. On the other hand, among the various surfactants, currently Pluronics are finding a special attention due to its biocompatibility and lower toxicity as compared to other surfactants [4]. However, only limited number of research studies has been carried out till date on the aqueous dispersion of CNT using Pluronic, especially at high concentrations.

The present paper reports the aqueous dispersion behaviour of various types of CNT (single-walled and multi-walled, both pristine and functionalized) using Pluronic F127. Various concentrations (0.1 to 0.3 wt .%) of CNT were dispersed in water using different concentrations of Pluronic, in order to find the optimum Pluronic concentration with respect to

CNT concentrations. A short (only one hour) and mild ultrasonication process was used to prepare the aqueous suspensions. The quality of aqueous suspensions was characterized using optical and scanning electron microscopy (SEM). The concentration of dispersed CNTs was measured using UV-Vis spectroscopy and the adsorption of Pluronic F127 on CNTs was confirmed through ATR spectroscopy. The dispersion behaviour of different types of CNT using Pluronic F127 has been compared with that using Sodium dodecylbenzene sulphonte (SDBS) at previously reported concentrations.

It was observed from the optical microscopy and SEM study that the optimum concentration of Pluronic F127 leads to homogeneous dispersion of various types of CNT (without agglomeration), similar to SDBS. UV-Vis spectroscopy revealed that the used dispersion process using both Pluronic F127 and SDBS leads to stable dispersion of high concentrations of CNT. However, the concentrations which could be dispersed using SDBS were higher than Pluronic F127, although the long term stability of the suspensions was higher in case of Pluronic F127. References

[1] M. F. Islam, E. Rojas, D. M. Bergey, A. T.

Johnson, and A. G. Yodh, Nano Lett., Vol. 3, No. 2 (2003) 269-273.

[2] Michael F. L. De Volder, Sameh H. Tawfick, Ray H. Baughman, and A. John Hart, Science, Vol. 339 (2013) 535-539.

[3] Yang K, Yi Z L, Jing Q F, et al., Chin Sci Bull, 58 (2013) 2082-2090.

[4] Gianni Ciofani,Vittoria Raffa, Virginia Pensabene,Arianna Menciassi, and Paolo Dario, Fullerenes, Nanotubes and Carbon Nanostructures,17 (2009) 11-25.


Figures

Figure 1: Aqueous dispersion (0.1 wt. %) of pristine single-walled nanotubes (a) and multi-walled nanotubes (b) prepared using Pluronic F127

Figure 2: Aqueous dispersion (0.1 wt. %) of pristine single-walled nanotubes (a) and multi-walled nanotubes (b) prepared using SDBS


Eva Rauls, Hazem Aldahhak, Wolf Gero Schmidt Theoretical Physics, University of Paderborn, Germany

[email protected]

S t r u c t u r e F o r m a t i o n o f O r g a n i c M o l e c u l e s o n S a l t

S u r f a c e s

Alkali salt surfaces are a promising alternative to the more common metal substrates for studying molecular self organisation. Potassium chloride (KCl) and sodium chloride (NaCl) are the most simple representatives of these materials and considered as prototype insulators with large band gaps >8 eV. A detailed understanding of the growth mechanisms of organic layers on these insulators is crucial for constructing optimized devices [1]. In particular,the structural ordering of the adsorbed molecules due to self assembling processes affects the physical properties relevant to the performance of the organic device [5].

PTCDA, as an organic semiconducting molecule with its characteristic rectangular shape [3], is of special interest in the engineering of 2D supermolecular nanostructures due to its ability to selfassemble in two dimensions [4]. Understanding the nature and strength of the intermolecular and molecule-substrate interactions that govern the ordering of molecular adsorbates is of great importance for controlling the arrangements of molecules on the surface and the properties of the resulting structures.

Using first principles methods including the necessary extensions for describing the long range dispersion interactions, we have investigated the adsorption and structure formation of PTCDA on both NaCl and KCl surfaces and partly confirm experimental findings [3,4].

For initiating structure formation, however, the presence of step edges of different kinds and with different defects is found to be responsible. We have calculated and compared the adsorption of PTCDA on both plain terraces and at surface step edges, supporting with our findings the observations of experimental set ups [3,4].

References

[1] S.A.Burke,W.Ji,J,M.Mativetsky, J,M.Topple,S.Fostner,H.-J.Gao,and P.Grütter, Phys. Rev. Lett.100,186104 (2008).

[2] M. Mura X.Sun,F.Silly H.T.Jonkman, G,A.D.Briggs M.R.Castell, and L.N.Kantorovich, Phys.Rev B 81,195412 (2010).

[3] M. Möbus, N. Karl, T. Kobayashi, Journal of Crystal Growth116 (1992) 495-504.

[4] Roberto Otero, Jose Maria Gallego, Amadeo L.Vazquez de Parga, Nazario Martin, Rodolfo Miranda, Adv. Mater. (2011) 23, 5148-5176.

[5] H. Aldahhak, W. G. Schmidt, and E. Rauls, Surf. Sci. 617, 242 (2013).

Figures

Figure 1: AFM image and ball-and-stick-model of PTCDA on KCl(100) in the so-called BWstructure

Figure 2: Adsorption positions of PTCDA at different defective sites at step edges


A. Redondo-Cubero1, K. Lorenz1, E.

Wendler2, D. Carvalho3, T. Ben3, F. M. Morales3, V. Fellmann4, B. Daudin4 1Instituto Superior Técnico, Campus Tecnológico e Nuclear, Univ. de Lisboa, Portugal 2Friedrich-Schiller-Universität Jena, Institut für Festkörperphysik, Max-Wien-Platz 1, Germany 3Dpto. de Ciencia de los Materiales e I.M. y Q.I., Facultad de Ciencias, Universidad de Cádiz, Spain 4Dépt. de Recherche Fondamentale sur la Matière Condensée, CEA/CNRS Group, “Nanophysique et Semiconducteurs,” CEA/Grenoble, France

[email protected]

I o n b e a m m i x i n g o f G a N - b a s e d q u a n t u m s t r u c t u r e s a t l o w

t e m p e r a t u r e s

Due to the strong polarization of wurtzite-type semiconductors (GaN and ZnO), ion-beam mixing has been suggested to increase the internal quantum efficiency through the formation of graded superlattices (SLs) [1]; however, the actual mechanism controlling the damage are greatly unknown. This work explores ion-induced intermixing and damage build up in GaN/AlN SLs with different dimensionality: quantum wells (QWs) and quantum dots (QDs) [3]. These systems show reduced intermixing by thermal treatments [2], but this work addresses the successful intermixing by ion implantation at very low temperatures. Sequential 100 keV Ar+ implantations were performed at 15 K and in situ analyzed by Rutherford backscattering spectrometry (RBS) in channelling mode. Further characterization was done by means of X-ray diffraction and transmission electron microscopy (TEM). Results agree with a 3-step damage model with an amorphization threshold of 40 displacements per atom (higher than for bulk GaN). However, the SLs show significant differences in the saturation level of defects at high fluences (>1015 cm-2), this being higher for QDs than for QWs. Compositional depth profiles obtained by TEM were fitted with an interdiffusion model, demonstrating that the higher damage in 0D structures is correlated with a larger diffusion length. Furthermore, the high radiation resistance of SLs as compared to bulk GaN is demonstrated.

References

[1] K.P. O’Donnell et al., Phys. Stat. Sol. RRL 1

(2011) 1 [2] C. Leclere, et al., J. Appl. Phys. 113, 034311 (2013). [3] A. Redondo-Cubero et al., Nanotechnology 24,

in press (2013).


Figures

Figure 1: HAADF-STEM images showing the different intermixing of QDs (a) and QWs (b) implanted to a fluence of 2·1016 cm-2. The inset shows the aspect of as-grown QDs for comparison. Brighter layers correspond to Ga-rich zones.

Figure 2: Depth-resolved information obtained for QDs and QWs implanted to a fluence of 2·1016 cm-2. (a) Ar profiles (symbols) extracted from RBS data compared with the expected ion profile from SRIM (line). (b) Damage distribution extracted from RBS data (symbols) compared with SRIM calculation (line). (c) Diffusion length calculated from HAADF fits following Eq. (3). (d) Intermixing efficiency Q calculated from Eq. (4). Note the semilogarithmic scale.


Nicolas Rispail1, Laura De Matteis2, Raquel

Santos3, Ana S Miguel3, Laura Custardoy4, Pilar Testillano5, María C Risueño5, Alejandro Pérez-de-Luque6, Christopher Maycock3,10, Pedro Fevereiro3,10, Abel Oliva3, Rodrigo Fernández-Pacheco4, Ricardo Ibarra2,4,8, Jesus M de la Fuente2,7, Clara Marquina8,9, Diego Rubiales1, Elena Prats1 1Instituto de Agricultura Sostenible-CSIC, Spain 2Instituto de Nanociencia de Aragon, Spain 3Universidade Nova de Lisboa, Oeiras, Portugal 4Laboratorio de Microscopías Avanzadas, INA, Spain. 5Centro de Investigaciones Biológicas-CSIC, Spain. 6IFAPA, Centro Alameda del Obispo, Spain. 7Fundación ARAID, Spain. 8Departamento de Física de la Materia Condensada, Universidad de Zaragoza, Spain. 9(ICMA)CSIC-Universidad de Zaragoza, Spain. 10Universidade de Lisboa, Portugal.

[email protected]

E v a l u a t i o n o f s e m i c o n d u c t o r n a n o c r y s t a l s a n d

s u p e r p a r a m a g n e t i c n a n o p a r t i c l e s f o r t h e

d e v e l o p m e n t o f n e w d i a g n o s t i c a n d c o n t r o l

m e t h o d s o f p l a n t a n d h u m a n f u n g a l p a t h o g e n

Recent developments in nanotechnology have demonstrated the usefulness of nanoparticles (NPs) for a wide range of application in biological systems [1,2,3]. All these applications make NPs promising tools for the development of novel strategies for the detection and control of plant and human diseases. However, before the design of such strategies, it is crucial to elucidate their interactions with target cells, cellular uptake and/or eventual excretion from cells, and the possible induction of toxic biological responses. Thus, we evaluated the interaction of two types of NPs, semiconductor nanocrystals (QDs) and superparamagnetic NPs (SiO2/MgO-magnetite) with fungal cells, as essential step to achieve the early detection of fungal pathogens and to address the feasibility of new NP-based smart delivery systems for its control. QDs were chosen because of their high sensitivity for detection in optical microscopy while the superparamagnetic NPs are biocompatible magnetic labels for magnetic detection.

NPs were tested with Fusarium oxysporum, an important plant fungal pathogen responsible for economically devastating vascular wilts of most crops [4] and an opportunistic pathogen of immune-compromised patients [5]. No completely efficient

control methods are available so far. Thus, an early diagnostic of the pathogen is crucial for its control.

Our results indicated a differential trend in NP internalization and toxicity depending on the NPs. Imaging of the F. oxysporum-NP interaction by means of confocal microscopy indicated that both types of NP showed high affinity for the pathogen and were quickly attracted by the fungal cells (Fig. 1).However, while the QDs readily penetrated the fungal hyphae, most of the SiO2/MgO-magnetite NPs remained attached to the fungal cell wall surface (Figs. 1).Toxicological assessment by evaluation of fungal germination and growth, production and accumulation of ROS, and cell viability indicated no or mild toxicity of both types of NPs at biological concentration. Altogether, the internalization and toxicity studies showed that the QDs and SiO2/MgO-magnetite NPs might be applied for the rapid and sensitive detection of F.

oxysporum. After adequate functionalization, they may also be useful for the control of this devastating pathogen. In both cases, in combination with a biomolecule able to target a desired formae

specialis, the NPs could act as inner-(in the case of QDs) or -surface (in the case of magnetic NPs) fungal labels. To this purposes, antibodies directed against


a highly specific pathogenicity-related protein of the fungus have been obtained and used to functionalize both types of NPs. The preliminary results on their functionalization and detection of the functionalized forms are also presented.

References

[1] Moros M, Hernaez B, Garet E, Dias JT, Saez B,

Grazu V, Gonzalez-Fernandez A, Alonso C, de la Fuente JM, ACS Nano,6 (2012), 1565-1577.

[2] Pankhurst QA, Thanh NTK, Jones SK, Dobson J, Journal of Physics D: Applied Physics,42 (2009).

[3] Mahmoudi M, Sant S, Wang B, Laurent S, Sen T, Advances Drug Delivery Review,63 (2011), 24-46.

[4] Di Pietro A, Madrid MP, Caracuel Z, Delgado-Jarana J, Roncero MIG, Molecular Plant Pathology,4(2003), 315-325.

[5] Boutati EI, Anaissie EJ, Blood,90(1997), 999-1008.

Figures

Figure 1: Detection of QDs and SiO2/MgO-magnetite NPs in a cell culture of F. oxysporum. Pictures represent visible and confocal micrographs and their corresponding transverse optical sections. Lower case letters indicate the orientation of the images. The green hurdle in the overview images marks the plane of the 3D section. F.

oxysporum was incubated with MPA-QDs (A) or SiO2/MgO-magnetite NPs (B)for16 h at 28ºC.


Baruch Rosenstein National Chiao Tung University (Taiwan)

B a n d g a p o p e n i n g i n g r a p h e n e o x i d e s

Single-layer graphene oxides were reduced to give reduced graphene oxides (rGO) with a broad distribution of oxide coverages in the previous work [1]. Electrical properties of rGO sheets were investigated simultaneously by density of states (DOS) and electron transport measurements. For electron transport measurements, two Ohmic-contacted electrodes were made on rGO and the temperature behavior of resistance and current-voltage (I-V) curves were studied. For the DOS measurement, see Fig., tunneling junction with a thin oxid layer was fabricated on rGO. From the resistivity of rGO sheets, the oxygen coverage of these sheets was estimated to be in the range from 8% to 23%. With an increase of the oxygen coverage on graphene surface, there is an increase of hopping energy and a decrease of localization length as well as the hopping distance from the electron transport measurement. For a high oxygen coverage rGO, the electron transport deviates significantly from the ideal two-dimensional Mott’s hopping conduction.

The measured DOS demonstrates a gap opening at a oxygen coverage of ~15%. Atomic structure of rGO is proposed here to describe the electron transport variation, band gap opening, and band-tail elongation phenomena. The continuous band gap opening in rGO is modeled by a tight binding model that complements band structure calculations at selected coverages. The main feature of the transition, at which two Dirac points coalecs, is the sixfold rotation symmetry breaking by the oxigen atom binding to a « bridge » of two carbon atoms. The gradual transition from graphene to graphene oxides is experimentally determined and theoretically modeled for the first time.

References

[1] S.T. Wang, Y.F. Lin, Y.C. Li, P.C. Yeh, S.J. Tang, B.

Rosenstein, T.H. Hsu, X.F. Zhou, Z.P. Liu, M.T. Lin, W.B. Jian, Apl. Phys. Let. 101, 183110 (2012).

Figures


Sascha Sadewasser1,2

1International Iberian Nanotechnology Laboratory, Av. Mestre José Veiga s/n, Braga, Portugal 2Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner Platz 1, Berlin, Germany

[email protected]

E l e c t r o n i c a n d s t r u c t u r a l g r a i n b o u n d a r y p r o p e r t i e s o f

c h a l c o p y r i t e s o l a r c e l l m a t e r i a l s

Polycrystalline p-type Cu(In,Ga)Se2 semiconductors represent the absorber material in thin film solar cells currently reaching the highest power conversion efficiency. Efficiencies above 20% are surprising considering the high density of grain boundaries in these films. Their role in the solar cell as well as their electronic structure are largely investigated and discussed. Recently, a number of scanning probe microscopy studies has contributed to the understanding of the grain boundary properties. In this talk we will present our contributions to this research field by employing Kelvin probe force microscopy (KPFM) and KPFM in conjunction with other techniques.

Several KPFM investigations of polycrystalline Cu(In,Ga)Se2 thin films have shown potential variations at grain boundaries [1], mainly exhibiting a lower work function around the grain boundary. However, recently also grain boundaries without potential variation and with higher work function have been found. These potential variations are typically assigned to a local band bending due to the presence of charges [2]. A study of polycrystalline samples with a variation in the In-to-Ga ratio is presented [3]. From a combination of KPFM with electron backscatter diffraction (EBSD), we could identify twin grain boundaries as predominantly neutral, whereas higher disorder grain boundaries are predominantly charged [4].

Additional understanding was gained from model samples consisting of large bicrystals on which, in addition to the KPFM characterization, also regular electrical characterization techniques and transmission electron microscopy were applied. These studies reveal a charge neutral barrier to majority transport for twin boundaries [4], while higher disorder (9 grain boundaries are charged and present a thin and high (~500 meV) electronic barrier for hole electrical transport [6], which can be attributed to the lower atomic density in the grain

boundary core by means of comparison to density-functional theory calculations [7]. References

[1] S. Sadewasser, Thin Solid Films 515, 6136

(2007). [2] D. Fuertes Marrón et al., Phys. Rev. B 71,

033306 (2005). [3] R. Baier et al., Sol. Energy Mat. Sol. Cells 103, 86

(2012). [4] R. Baier et al., Appl. Phys. Lett. 99, 172102

(2011). [5] S. Siebentritt et al., Phys. Rev. Lett. 97, 146601

(2006). [6] M. Hafemeister et al., Phys. Rev. Lett. 104,

196602 (2010). [7] S.S. Schmidt et al., Phys. Rev. Lett. 109, 095506

(2012).


Juan Manuel Serrano Núñez Sesderma Laboratories, Polígono Industrial Rafelbuñol C/Massamagrell 3, Rafelbuñol 46138 (Valencia) Spain

[email protected]

L i p o s o m e s : T o p i c a l a n d O r a l B i o a v a i l a b i l i t y

Liposomes are small vesicles composed of one or more lipid bilayers. The size can go from 30nm up to several microns. Liposomes can encapsulate hydrophilic solutes in the aqueous core and lipophilic solutes in the membrane. These vesicles can be classified according to their size and number of bilayers: Multilamellar (100-10.000nm), Small Unilamellar (less than 100nm), Large Unilamellar (100-500nm). Sesderma manufactures very uniform, unilamellar liposome populations of between 50-150nm.

The advantages of liposomes are that, the structure is very similar to biological membranes and thus, are biodegradable and non toxic, they can reach the deepest layers of the skin, they provide a sustained release of the active ingredients, they prevent the oxidation and degradation of the ingredients and they show higher efficiencies at lower concentrations.

We have carried out three different experiments on topical bioavailability: liposome penetration through skin, hair follicles and nails.

In the first one, we compared the permeation capacity through human skin, using a Franz Diffusion Cell, of two different substances encapsulated and not encapsulated in liposomes: fluorescein and sodium ascorbate. Aliquots were taken from the receptor chamber at different times. The concentration of sodium ascorbate was determined by high performance liquid chromatography with ultraviolet detection (HPLC-UV) and that of fluorescein by spectrofluorimetry. The results were as follows:

These results might be due to the nature and size of the active ingredients, and the characteristics of the layers of the skin. The epidermis is a stratified layer

with plenty of cells, this is why liposomes can get through it easier than the ingredients in solution. Fluorescein can diffuse faster through the epidermis than sodium ascorbate because fluorescein is more lipophilic than sodium ascorbate. The dermis has less cells and more fibres, and has a greater aqueous volume, so the preparation that permeates faster is that of sodium ascorbate solution due to its hydrophilic nature and small size. Finally, we can confirm that liposomes help substances pass through the skin.

In the second case, liposome ability to go across the follicular canal was assayed with liposomal fluorescein. The skin samples were extracted from human abdomen and the equipment used was the same as in the prior experiment: Franz Diffusion Cell. Pictures were taken at different times with a fluorescence microscope. We concluded that the follicular canal is an excellent penetration enhancer; a liposome reservoir is formed, facilitating its pass through the hair follicle and into the dermis.

In the third experiment, we assessed the penetration capacity of liposomal fluorescein on one hand and a solution of fluorescein on the other hand, through human nails. The equipment utilized was a Franz Diffusion Cell with a coupling device for nails. Aliquots were taken from the receptor chamber at different times and the concentrations of fluorescein were determined by spectrofluorimetry. The results showed that the maximum quantity of absorption for both formulations was obtained after 2 days in contact with the products. The concentration of fluorescein (2.96 ±1. 0.2 μg/cm²) for the liposomal formulation was 2.5 times higher than the solution (1.22 ± 0.2 μg/cm²). However, the permeability constant is very similar for both preparations: fluorescein solution (0.006 ± 0.002 cm²/s) and liposomal fluorescein (0.008 ± 0.001 cm²/s). We could also observe that there was an increase in the thickness of the nail


treated with liposomal fluorescein whilst there were no changes observed in the nail treated with the solution of fluorescein.

Ascorbic Acid Oral Pharmacokinetics in Rats

Aim: Compare the pharmacokinetics of two sodium ascorbate formulations: - Sodium ascorbate solution (extemporaneously prepared). - Sodium ascorbate encapsulated in liposomes. Method:

The day prior to the administration of the formulations, 12 Wistar rats (280-310 g) were cannulated in the jugular vein to allow blood sampling at preset times. A volume of 2.5 mL of each fresh formulation was administered orally as single dose with intraoesophageal cannula. Six replicates were performed for each formulation. 200 μl blood samples were taken at the following times: 0, 15 , 30, 45 , 60, 90 , 120 minutes and 3, 4 , 5, 6 , 7, 8 , 10, 12 , 23, 26 hours . The samples were centrifuged at 2000g for 5 min to obtain plasma which was immediately deproteinized with icecold MPA 10% (metaphosphoric acid). The samples were filtered through a pore diameter of 0.45μm. The analytical method used to measure vitamin C (sodium ascorbate) was HPLC-UV with UV detection at 254nm. The mobile phase used consisted of a KH2PO4 (0.1M) solution: ACN (95:5) at a pH of 2. As the stationary phase, the column Sherisorb ODS1 5uM 25x0.4mm was used and the selected flow rate was 1 ml / min. The injection volume used was 60 μL. Results:

Plasma concentration versus time after oral administration of 250 mg of sodium ascorbate formulated in an extemporaneous solution (black line) or in liposomes (green line). Mean ± SEM, n = 6.

Conclusions: liposomes enable a better control of the release of the drug in plasma and maintains it for a longer period of time. A liposomal formulation of sodium ascorbate requires a smaller dose to reach the desired plasma concentration and, therefore, the desired therapeutic effect.

References

[1] ELKEEB, R., ALIKHAN, A., ELKEEB, L., HUI, X. &

MAIBACH, H. I. 2010. Transungual drug delivery: current status. Int J Pharm, 384, 1-8.

[2] ISHIDA, A., OTSUKA, C., TANI, H. & KAMIDATE, T. 2005. Fluorescein chemiluminescence method for estimation of membrane permeability of liposomes. Anal Biochem, 342, 338-40.

[3] KARLSEN, A., BLOMHOFF, R. & GUNDERSEN, T. E. 2005. High-throughput analysis of vitamin C in human plasma with the use of HPLC with monolithic column and UV-detection. J Chromatogr B Analyt Technol Biomed Life Sci, 824, 132-8.

[4] KLIGMAN, A. M. & CHRISTOPHERS, E. 1963. Preparation of Isolated Sheets of Human Stratum Corneum. Arch Dermatol, 88, 702-5.

[5] O'GOSHI, K. & SERUP, J. 2006. Safety of sodium fluorescein for in vivo study of skin. Skin Res Technol, 12, 155-61.

[6] SZNITOWSKA, M. & BERNER, B. 1995. Polar pathway for percutaneous absorption. Curr Probl Dermatol, 22, 164-70.

[7] TORRES-MOLINA, F., ARISTORENA, J. C., GARCIA-CARBONELL, C., GRANERO, L., CHESA-JIMENEZ, J., PLA-DELFINA, J. & PERIS-RIBERA, J. E. 1992. Influence of permanent cannulation of the jugular vein on pharmacokinetics of amoxycillin and antipyrine in the rat. Pharm Res, 9, 1587-91.


Carla Silva Centre for Nanotechnology and Smart Materials (CeNTI), Vila Nova de Famalicão, Portugal

[email protected]

N a n o m a t e r i a l s – f r o m s y n t h e s i s t o s o l u t i o n s

The potential of nanotechnologies and nanomaterials has been greatly explored over the past years to obtain new and more sustainable products and processes. The intensive research that has been conducted in Nanosciences and Nanotechnologies (N&N) has led to the development of innovative nanomaterial’s and applications. Nevertheless, there is still a huge gap between scientific production and industrial utilization of nanomaterials and nanotechnologies. Although there are several unsolved issues regarding the safe handling and use of nanomaterials, the main obstacle to the commercial exploitation of these new technologies and materials stands on the knowledge transfer and the upscaling feasibility to the industrial processes. In this communication, several examples will be given on the synthesis and use of nanomaterials and on the application of nanotechnologies to produce innovative products to be used in different industries and substrates (ranging from textile, wood, ceramic, cork and others).


D.S.Sutherland, J. Malmström, S. Kristensen, A.S.Andersen, T Bøggild, G.A. Pedersen, M. Cole and L.N. Nejsum iNANO Center Aarhus University, 14 Gustav Wieds Vej, Aarhus, Denmark

[email protected]

P r o t e i n n a n o p a t t e r n s p r e p a r e d b y c o l l o i d a l

l i t h o g r a p h y t o s t u d y c e l l u l a r a d h e s i o n c o m p l e x e s

Mammalian cells are highly dependent on their surroundings for their fate, function and survival. The microenvironment surrounding a cell provides a rich and instructive set of signals involving both biochemical and mechanical stimuli with both matrix- bound and soluble signals. The extracellular matrix (ECM) provides both a mechanical support and a range of surface bound stimulatory signals. The cell adhesion complexes to both the extracellular matrix and to other cells are important sensing, signalling and communicating structure within a cell. One important form, identified in vitro, is the focal adhesion (FA) complex that regulates the mechanical connection to the ECM. FAs consist of assemblies of integrin receptors, connecting multiprotein intracellular complexes and the actin cytoskeleton to the ECM. Focal adhesions (FAs) also contain a broad set of signalling molecules and believed to have a major role in most of the signalling and sensing interactions occurring between the ECM and the cell. When cells interact with synthetic or natural materials the complex mixture of proteins adsorbing at the surface create a microenvironment for the cell and modulate the cellular function at the material.

Nanometer scale topographic and chemical structures can provide cues and organization signals imposing a pattern on the extracellular matrix molecules adsorbing to nanostructured materials. Here a route to define protein presenting nanostructured interfaces based on colloidal monolayer masks and traditional lithographic steps will be described. Dispersed monolayers resulting from sequential electrostatic binding to oppositely charged surfaces results in short range ordered arrays of particles and can be utilized to generate one nanostructure per particle. The generated patterns have no long range order and are homogeneous over large areas (10’s of cm2) and can be chemically functionalized to enable protein patterning [1]. These

materials are used to pattern specific ECM and cell-cell adhesion molecules for use in understanding and steering development and signaling at adhesive complexes such as integrin based focal adhesions and cadherin based adherence junctions. Previous studies have used different ECM protein patterns (e.g. Fibronectin [2,3], Vitronectin [3], Osteopontin [4]) to study the development of focal adhesions and their connection to the cytoskeleton.

Here colloidal lithography can be used to generate protein nanopatterns with feature sizes from 60nm-3000nm over large areas (10-100cm2). Figure 1 shows SEM images of structured silicon wafers with chemistry based on Au/SiO2. For smaller sizes. Surface chemical functionalization using alkanethiols to give the gold domains on the surface a hydrophobic chemistry and PLL-g-PEG to give the silica background regions a protein rejecting character (in our hands PLL-g-PEG reduces protein binding by >97%). Neutravidin or streptavidin was immobilized into the hydrophobic domains and used to immobilise biotinylated Protein A into nanopatterns. Site specific coupling via protein A allowed immobilisation of Fc tagged E-cadherin and I-CAM1 ectodomains. The role of ligand patch size on adhesion and actin skeleton development has been investigated in MDCK cells and activated THP-1 monocytes respectively. Cellular E-Cadherin (fluorescently labelled) shows nanoscale organization above the protein nanopatches with a control of adhesion complex steered from the surface. A threshold behaviour of cell adhesion is seen where cells only adhere to patch sizes of 200nm and above and shows a size dependent cell spreading and actin organisation. This suggests a lower number of ECadherins for the formation of mechanically stable adhesions of >17 molecules [5]. Nanopatterns of ICAM have been prepared in microfluidic channels and relevant for the study of the adhesion of


activated monocytes mimicking the recruitment process at wound sites invivo.

Patterns of proteins can provide be made by colloidal lithographic patterning and subsequent chemical functionlisation from a broad range of proteins. These protein nanopatterns can contain functional and oriented protein layers mimicking the presentation at ECM or cell surfaces. The size of the patch of adhesive ligands shows size dependent influence on the adhesion of cells, the development of adhesion complexes (both focal adhesions and adherens junctions) and their connection to the cellular cytoskeleton. Colloidal lithography represents an interesting route to generate materials giving an external control of cell adhesion complex formation and development as well as tools to study cellular process. References

[1] H. Agheli, J. Malmstrom, E.M. Larsson, M.

Textor and D.S. Sutherland Nano Letters 6 (2006) 1165-1171

[2] J. Malmström, B. Christensen, H.P. Jakobsen, J. Lovmand, E.S.Sørensen, D.S.Sutherland Nano Letters 10 (2010) 686-694

[3] J. Malmström, J. Lovmand, S Kristensen, M Sundh, M Duch and D.S.Sutherland Nano Letters 11 (2011) 2264-2271

[4] J. Malmström, B. Christensen, J. Lovmand, E.S.Sørensen, M. Duch, D.S.Sutherland Journal of Biomedical Materials Research A 95A(2010) 518-530

[5] S. Kristensen, G. Pedersen, L. N. Nejsum and D.S.Sutherland Nano Letters 12 (2012) 2129-2133

Figures

Figure 1: SEM images of a colloidal lithography produced patterns of gold chemistry (circular domains) / Silica chemistry (background) of diameter 100nm 8lower left), 160nm (upper right) and 200nm (upper left).

Figure 2: Immunofluorescent stained a patterns of I-CAM1 of 800 nm diameter.


Sara Teixeira1, Klaus Kuehn1, Pedro

Martins2, Ana Catarina Lopes2, Maria Gabriela Botelho3, Senentxu Lanceros-Mendez2, and Gianaurelio Cuniberti1 1 Technische Universität Dresden, Germany 2Centro/Departamento de Física, Universidade do Minho, Braga, Portugal 3 Centro/Departamento de Química, Universidade do Minho, Braga, Portugal

[email protected]

P h o t o c a t a l y t i c a l d e g r a d a t i o n o f a n t i b i o t i c s p r e s e n t i n

w a t e r

The presence of antibiotics in water, due to their over- and misuse, has become a matter of considerable concern since they can lead to negative effects on humans and adverse environmental effects. These effects include the development of antibiotic resistance in microorganisms and toxicity to micro flora and -fauna [1-3].

Despite antibiotics entering the sewer network and reaching the wastewater treatment plants, the treatments applied are ineffective for their removal. Therefore, photocatalysis has become an attractive process to promote their degradation since it allows a rapid and efficient removal, transforming the initial compound into harmless substances, as CO2 and water [4].

Because of their physical and chemical stability, no toxicity, and low cost, TiO2 and ZnO are promising photocatalysts [5]. However since they have large band-gap energies (higher than 3 eV) they just absorb radiation of wavelengths inferior than 390 nm (5 - 10 % of the incident solar radiation), corresponding to the ultraviolet region.

The use of an artificial light source is the main source of costs which suggests the use of sunlight as an economically and ecologically source. To overcome this limitation, it is necessary to increase the absorbance of the visible light by the photocatalytic nanoparticles. Doping the photocatalysts has been found to be a fruitful way to narrow the band gap or split it into several sub-gaps. Additionally, some dopants may also prevent the fast recombination of the photogenerated electron-hole pair, responsible for decreasing the photocatalytic activity.

Furthermore, the application of photocatalyst dispersed in water shows some disadvantages, as the difficulty of radiation penetration in the aqueous solution and the difficulty to remove the catalyst at the end of the process. Therefore, there have been studied various forms of attachment of photocatalyst particles onto supports that are easily removable from water.

Hence, this project aims to produce and evaluate the photoactivity of Polyvinylidenefluoride-co-trifluoroethylene (PFDV-TrFE) membranes filled with different photocatalysts: TiO2, doped TiO2 with three dopant concentrations (Erbium 0.5 %, 1 % and 3 %) and ZnO. References

[1] Klauson, D., J. Babkina, et al., Catal Today

Catalysis Today, 151 (2010) 39-45. [2] Homem, V. and L. Santos, Journal of

Environmental Management, 92 (2011) 2304-2347.

[3] Isidori, M., M. Bellotta, et al., Environment International, 35 (2009) 826-829.

[4] Hapeshi, E., A. Achilleos, et al., Water Research, 44 (2010) 1737-1746.

[5] Fujishima, A., et al., Journal of Photochemistry and Photobiology C: Photochemistry Reviews, 1 (2000) 1–21.


A.V. Vasin, A. V. Rusavsky, V.A.Tyortyh,

A.N. Nazarov, V.S. Lysenko Lashkaryov Institute of Semiconductor Physics, NAS of

Ukraine, Kyiv, Ukraine

Institute of Surface Chemistry. NAS of Ukraine, Kyiv,

Ukraine

[email protected]

S t r o n g a n d t u n a b l e w h i t e

p h o t o l u m i n e s c e n c e f r o m

c a r b o n i n c o r p o r a t e d

n a n o s t r u c t u r e d s i l i c a

Carbon incorporated silicon oxide nano-composite

(SiO2:C) is one of new promising light-emitting

materials. Unfortunately, origin of light emitting in

these materials has not yet been identified. The main

“candidates” suggested as light emitting centers were

(1) point defects in SiO2 network (oxygen deficiency

centers), (2) Si-O-C or Si-C isolated bonds, and (3) C or

SiC nano-clusters. We believe that most reasonable

hypothesis is light emission by carbon nanoclusters.

Recently it was demonstrated that carbon nano-

clusters with passivated surface exhibit strong visible

photoluminescence (PL) with emission photon energy

depending on the size of the cluster [reviewed in Ref.1

and Ref.2].

In present report we analyze structure and light

emission properties of two types of SiO2:C materials:

porous SiO2:C layers on Si wafers and SiO2:C powders.

Carbon incorporated porous silicon oxide layers (por-

SiO2:C) were fabricated by successive procedure of

thermal treatment of porous silicon in flow of

acetylene (in temperature range of 850-1150 oC)

followed by oxidation in flow of wet nitrogen or wet

argon in temperature range of 850-1050 oC [3-5]. The

other type of nanostructured SiO2:C composite was

fabricated by successive chemical modification of

nano-silica powder (specific surface area of 300 m2/g,

particle size about 10 nm) by hydrocarbons or

hydrocarbosiloxanes followed by calcinations at

temperature up to 700 oC in inert ambient (pure

nitrogen flow or vacuum). Correlations of fabrication

conditions, local bonding structure and light emission

properties have been studied. The main goal of the

work was to check our hypothesis on carbon cluster

origin of photoluminescence in nanostructured SiO2:C

materials

Porous SiO2:C layers. It has been demonstrated that

broad band light emission of por-SiO2:C is composed

by two bands: (1) broad band centered at about 500-

600 nm and (2) blue shoulder with maximum intensity

at about 440 nm. The 500-600 nm band vanished

completely after annealing in oxygen that was

accompanied by strong reduction of carbon content in

the layer, so that we assign this band to presence of

carbon (carbon related band). Moreover, we have

found spectral shift of carbon related PL band from

orange to green spectral region with decrease of

carbonization temperature (Figure 1). This shift is well

explained by size-dependent PL shift observed in

carbon nano-dots [1-2]. .

SiO2:C powders. General idea of the material

synthesis procedure was to attach hydrocarbon

radicals to surface of fumed silica nano-particles

(SiO2:OH nanopowder) by chemical treatment

(formation of SiO2:CnHm precursor nano-powder) with

subsequent annealing in inert atmosphere (formation

of SiO2:C composite powder). The series of the

materials with predominant Si-O-CnHm and Si-CnHm

bonding configuration between silica nanoparticles

and hydrocarbon radicals as well as the series of

materials SiO2:CnHm with the n in range of 1-9 have

been fabricated and studied.

It was demonstrated that light-emission properties of

SiO2:C are not dependent on type of “bridging” bonds

in the SiO2:CnHm precursor while it was very sensitive

to amount of carbon and annealing

temperature/duration. The less carbon incorporation

in the powder the larger temperature it needs for PL

activation. Vice-versa, the more carbon in the powder

the easier it goes black due to graphitization of

carbon. PL efficiency is suggested to be determined by

two competitive processes: nucleation of light

emitting small carbon clusters and growth of large

graphite-like precipitates that do not emit light. Light

emitting powders were usually of light-gray or light-

brown color.

The other important observation was the red spectral

shift of PL maximum intensity with increase of

annealing temperature (Figure 2) and/or number of

carbon atoms in attached hydrocarbon radicals. Such

spectral shifts of PL band is quite similar to that


observed in porous SiO2:C (Figure 1). This shift cannot

be explained in terms of local defects or isolated

bonds, however, it is in good agreement with the

effect of the size of carbon cluster (the smaller cluster

size the larger gap between HOMO and LUMO

electron states).

PL decay time in SiO2:C (both porous layers and

powders) was measured to be less that 10 ns. Short

decay time is also hardly compatible with point

defects hypothesis. Defect related light emission in

silicon oxide in visible spectral range is associated with

radiative recombination from triplet state to ground

state (T1 → S0) [6]. Such recombination (i.e.

“phosphorescence”) is natively slow process with

characteristic decay time of micro- and milliseconds.

In summary, it is demonstrated that light emission in

SiO2:C is originated most likely from carbon nano-

precipitates. We have not observed carbon clusters

directly in light-emitting material but all experimental

data are shown to be self consistent in frame of the

“carbon cluster hypothesis”.

Size dependent spectral properties of SiO2:C makes

possible “color engineering” of white light. Figure 3

illustrates that PL spectrum of SiO2:C can be almost

ideally tuned to natural day light. Excellent spectral

properties of white light emission along with lack of

expensive heavy metal dopants make SiO2:C material

extremely attractive as luminophor for artificial

lighting applications.

References

[1] Baker Sh. N., Baker G. A. Angew. Chem. Int. Ed.

49 (2010) 6726-6744.

[2] Kang H. Li. Zh., Liu Y., Lee Sh.-T. J. Mater. Chem.

22 (2012) 24230–24253.

[3] Vasin A. V., Ishikawa Y., Shibata N., Salonen J.,

and Lehto V. P., Jpn. J. Appl. Phys. 19 (2007)

L465–467.

[4] Ishikawa Y., Vasin A.V., Salonen J., Muto S.,

Lysenko V.S., Nazarov A.N., Shibata N., Lehto V.-

P., J. Appl. Phys. 104 (2008) 083522-1–083522-

6.

[5] Vasin A., Rusavsky A., Nazarov A., Lysenko V.,

Rudko G., Piryatinski Yu., Blonsky I., Salonen J.,

Makila E., Starik S. Phys. Status Solidi (a) 209

(2012) 1015–1021.

[6] Skuja L. Journal of Non-Crystalline Solids 239

(1998) 16-48

Figures

400 500 600 700 800

3

2

PL intensity, arb.un.

Wavelength, nm

carbonization

1 - 850 oC

1 - 950 oC

1 - 1050 oC

1

Figure 1: Time resolved PL spectra of por-SiO2:C layers synthesized

using carbonization temperature 850 oC (spectrum 1), 950

oC

(spectrum 2) and 1050 oC (spectrum 3). Excitation by 337 nm.

400 450 500 550 600 650 700

4 3 2

Norm

alized PL intensity, arb.un.

Wvelength, nm

1 - 500 0C

2 - 540 0C

3 - 580 0C

4 - 600 0C

446 nm 523 nm

1

Figure 2: PL spectra of SiO2:C powder synthesized using annealing

temperature 500 oC (spectrum 1), 540

oC (spectrum 2), 580

oC

(spectrum 3), and 600 oC (spectrum 4). Excitation by 370 nm.

400 450 500 550 600 650 700

SiO2:C powder

Emission intensity, arb.un.

Wavelength, nm

Black body, 6000 K

Figure 3: Spectral distribution of light emission of black body at

6000 K (roughly corresponds to spectral distribution of Sun

radiation) and representative SiO2:C powder ( 360 nm excitation).


Hua Chun Zeng

Department of Chemical and Biomolecular

Engineering, Faculty of Engineering,

National University of Singapore

[email protected]

D e v e l o p m e n t o f I n t e g r a t e d

N a n o c a t a l y s t s

Despite decades of research, the prevailing catalyst

technology for heterogeneous catalysis remains

largely as an art than as a science. Rapid

development of nanotechnology and materials

chemistry in recent decades however provides us

new capacity to reexamine the existing catalyst

design and processing methods. An important

advancement from the above research is that the

catalytic materials can now be prepared in a greater

precision. With newly gained controllability over

particle composition, structure, shape and

dimension, researchers in this field will be able to

enter next phase of catalyst development for

general heterogeneous catalysis if they find new

bridging ways between the old and new

technologies. One possible way seems to be

integrating active nanostructured catalysts onto

design-built catalyst supports which are “not-so-

nano” in dimension but with accessible hierarchical

pore and cavity spaces. Note that such catalyst

devices still remain the essence of traditional

catalysts (i.e., “catalyst-plus-support”), but they

involve different design and integration processes in

construction and they show good advantages in

performing catalysis.

In this presentation, we will report some of our

recent progress in this technologically important

area – development of state-of-the-art catalytic

nanomaterials [1-6]. In particular we will first

address the current issues of nanocatalysts research,

and then introduce various possible forms of design

and types of integration for catalyst fabrication with

increasing compositional and structural complexity,

including tunable smart features and functionalities.

It is further proposed to anchor sub-nanometer

metal-clusters, organometallic complexes,

organocatalysts and enzymes onto surfaces of

device-walls and shell-pores of this type of catalysts.

At the same time, we will also address the important

roles of surface analytical techniques in the

development of these new-generation

heterogeneous catalysts.

References

[1] H. C. Zeng, Nanostructured Catalytic Materials:

Design and Synthesis, in the Dekker

Encyclopaedia of Nanoscience and

Nanotechnology; Marcel Dekker: New York

(2004) 2539-2550.

[2] H. C. Zeng, Integrated Nanocatalysts, Acc.

Chem. Res. 46 (2013) 226-235.

[3] Z. Li and H. C. Zeng, Surface and Bulk

Integrations of Single-Layered Au or Ag

Nanoparticles onto Designated Crystal Planes

110 or 100 of ZIF-8, Chem. Mater. 25 (2013)

1761-1768.

[4] C. C. Li and H. C. Zeng, Coordination Chemistry

and Antisolvent Strategy to Rare-Earth Solid-

Solution Colloidal Spheres, J. Am. Chem. Soc.

134 (2012) 19084-19091.

[5] J. Dou and H. C. Zeng, Targeted Synthesis of

Silicomolybdic Acid (Keggin Acid) inside

Mesoporous Silica Hollow Spheres for Friedel-

Crafts Alkylation, J. Am. Chem. Soc. 134 (2012)

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[6] M. L. Pang, A. J. Cairns, Y. L. Liu, Y.

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Highly Monodisperse MIII-Based soc-MOFs (M =

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13176-13179.

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Cover image: SEM micrograph showing the morphology of the well-orderd Si nanobelt arrays

Credit: Lifeng Liu (International Iberian Nanotechnology Laboratory -INL, Portugal)

Edited by

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