The web's foremost resource on soft condensed matter.Newsletter

• Image Credits: Plastic Love | Chang-Soo Lee, Chungham University

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February | 2013 | #49

4 years of SoftMatterWorld: New website for the New Year

Its all change at SoftMatterWorld for the new year - we have totally redesigned our website for a fresh, modern look. Take a minute to browse the new site – you’ll find all the usual features including links to the month’s articles, past newsletters, conferences, the world map and more.

In addition we will be featuring more articles by our stu-dent interns, updated forms make the registration process much easier and the gallery will be expanded.

This makeover might even be confusing to some of our dedicated readers as it is the first time the site has changed its layout since it was founded in 2008. The new layout is ca-pable of hosting much more information and multimedia while remaining cross-browser and device compatible: the site will function on any size screen from an smartphone to a high definition monitor. Some of the other notable changes are:

• The navigation has been stripped down to focus on the key elements of the site and newsletter.

• There has been an introduction of a "home" page: a vibrant display of each months featured articles and upcoming conferences.

• Along the bottom of the site are 4 key links allow-ing users to always find their way back to the Home Page, Archives, Site Map and Contacts Page.

• In addition to our Facebook page we have also opened a Twitter and Youtube account. The you-tube account will simply be a way for us to link to supplementary videos posted by the authors of our featured articles.

• Integration of new sign-up forms.

In the coming weeks there will be many updates such as RSS feeds and an improved Global Network Page.

In the meantime we hope you enjoy the new look. Should you notice any errors or dead links email the webmaster at:

• webmaster@softmatterworld.org.

Welcome to the 2013 new year’s edition of the newsletter. We have some big changes to announce this month, a to-tally updated website and look for softmatterworld.org and the results of our first calendar competition - congratulations to all of our members who submitted a successful image. Everybody at SoftMatterWorld would like to wish our members around the globe a successful and productive new year.

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2013Calendar Competition

januaryron pandolfi

februarychang-soo lee

marchkeng-hui lin

aprilneda ghofraniha

may

miha ravnikslobodan zumersimon copar

junegiuliano zanchetta

julyyilong han

augustjung-hyun noh

septembersungjune parkalexander böker

octoberrajdeep deb

novemberajay gopinathan

december marco pinna

2013 Calendar Competition Winners Announced We are proud to announce the winners of our first SoftMatterWorld Calendar compe-tition. We received submissions from all round the world and were able to select some amazing images to include in the calendar. We would like to offer any interested fellow soft matter colleagues a full color, minia-ture desk calendar. This offer is not limited to members of our mailing list. Any research-er, student or artist who finds these images as visually intriguing as the science behind them is welcome to email the editor at editor@softmatterworld.org with your mailing address and we will gladly send you a copy.

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Statistics of DNA Capture by a Solid-State NanoporeMirna Mihov i lov i c , Nicho las Hager ty, and Derek Ste in . PRL 110, 028102 (2013)

DNA molecules can be elec-trophoretically captured by solid-state nanopores. Voltage-based nanopores allow measurement of variation in current through a pore. The variation is dependent on the translocating material, allowing the determination of capture location along the strand (the part of the strand that first enters the pore). This information is vital to extract-ing sequence-related information.  Brown University researchers have constructed an 8nm-wide solid-state nanopore in a 20nm-thin silicon nitride membrane. This membrane divided two reservoirs of electrolytic solution, with the pore allowing for diffusion and electrical current. Occupation of the nano-pore by DNA strands caused fluc-tuations in the current, depending on capture location. As Figure 1 demonstrates, mol-ecules with zero folds were desig-nated type 1, strands with a fold producing two segments of un-equal length type 2-1, and strands folded equally in half type 2. Type

1 molecules produced a single dip in current, as did type 2 to a greater extent. Type 2-1 produced an initial drop in current on the magnitude of a type 2 before mimicking a type 1 as the shorter half of the folded strand slipped through the nano-pore. Only molecules with no folds or a single fold were included in the analysis.  The experiment showed a strong bias for capture along the ends of the DNA strands. The research group presented a mathematical model that accounts for this phe-nomenon, arguing that the  mole-cule does not, as previous research suggested, spend time finding an energetically favorable position in relation to the nanopore. They ar-gue instead that the capture loca-tion is dependent on the configu-rational entropy of the strand when it approaches the pore. They also analyzed the relationship between the length of a segment and its translocation speed. Understanding the passage of DNA through nanopores is nec-

essary to be able to interpret se-quence-related data. Such knowl-edge may lead to the realization of cost-effective and reliable nano-pore-based sequencing of DNA, without the need for polymerase chain reaction amplification (PCR) or chemical markers. The full article can be found here.

Michael Lane

Cotton Fabrics with Single-faced Superhydrophobicity Yuyang , L . , X in , J . H. , &; Cho i , C . -H. (2012) . Langmuir, 28(50) , 17426-17434. do i : 10 .1021/ la303714h

Standard cottons can readily acquire stains and contamination from beverages, blood, bacteria, and germs. However, cotton is also soft, breathable, has a low possibility for skin irritation, and the ability to bio-degrade. A research collaboration between groups in New Jersey and Hong Kong have developed cotton with single-faced superhydrophobicity that brings to-gether these properties and the ability to be stain re-sistant through asymmetric wetting.

FIG. 1. (a) A nanopore captures DNA from solu-tion and initiates electrophoretic translocation by forming a hairpin. (Detail) TEM image of the 8-nm-wide nanopore used. (b) Ionic current traces from translocation events of types 1, 2-1, and 2 indicate the capture locations. (c) The ionic current trace of a folded DNA molecule shows t2, ttot, and ECD.

Fig 1

FIG. 2: Pictures demonstrating how the treated cotton reacts to dyed water.

(a) Water droplets are placed on the hydrophobic side creating beads while

the cotton on the hydrophilic side absorbs the water. (b) The upper image

shows the result of wetting and cutting the hydrophilic side of the material.

The lower image shows that when the hydrophilic side of the cotton has ab-

sorbed water, the hydrophobic side maintains the ability to repel water.

Fig 2

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ConferenceListings dates and deadlnes

COMPLOIDS presents: Physics of Complex Colloids � Early Bird Registration - February 19th

COLLOIDS and ENERGY 2013 � Early Bird Registration - February 22nd

Dense Flows of Soft Objects � Registration Opening - February 18th

Advances in Microfluidics & Nanofluidics � Abstract submission - February 21st

IOP: Advanced School in Soft Condensed Matter � Poster Abstract Deadline: February 25th

� Registration Deadline: February 25th

We hope you enjoy broWsing softmatterWorld.org and come back soon

linda s. hirst and adam ossoWski

SoftMatterWorld.org

The research team used a simple foam finishing process to make one side of the cotton superhydro-phobic (water repelling) while keeping the other side of the cotton hydrophilic (water absorbing). Unlike past procedures, this process incorporates air into the aqueous solution. The incorporation of air allows for fewer finishing chemicals to be applied to the cotton and ensures even distribution of the resulting foam. In addition, the permeability of the foam into the fabric can be manipulated by changing the air content. The surface morphology and chemical composi-tion of the treated cotton was tested using a Scanning Electron Microscope (SEM) and Energy-Dispersive X-ray (EDX or EDS) spectrum of both sides of the treated fabric. The SEM images showed no morphological difference between the two sides, but the EDX spec-trum showed a fluorine peak on the hydrophobic sur-face demonstrating the application of foam to only one side. Wettability was observed by evaluating how readily both sides of the treated cotton absorb wa-ter (Figure 1). One side of the material absorbs water while the other side does not creating water droplets on its surface (Figure 1a). Even after the hydrophilic side has absorbed water, the hydrophobic side main-tains the ability to resist moisture (Figure 1b). The foam finishing process allows for more desir-able properties to be added to cotton while retaining the original properties of the fabric. Additional practi-cal applications of this new asymmetric fabric include desalination of seawater, flow management in fuel cells, and water/oil separation. Read the full article at ACS Publications, Langmuir. To watch a video of these experiments in live action you can visit the Soft Matter World you-tube channel.

Amanda Baijnauth

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Call for submissions: Noticeboard & Conference Listings Bulletin for Spring 2013

For the March 2013 News-letter we will be releasing a double feature bulletin for the Noticeboard and Conference Listings. Please send all open-ings or conferences to editor@softmatterworld.org And remember, all postings are advertised free of charge.