Archive for September, 2011

Oppositely Charged Hairy Colloids

Read for free here until 28 October

Oppositely charged colloidal particles exhibit fully reversible assembly under varying salt concentrations in water. Fluorescent polystyrene colloidal particles are charged by a grafted polyelectrolyte brush. Below a certain concentration oppositely charged colloids form clusters and gels with a fractal nature. These particles are a promising step toward a reversible and controlled self-assembling system in water, using colloidal particles as building blocks.

 

Evan Spruijt, Henriëtte E. Bakker, Thomas E. Kodger, Joris Sprakel, Martien A. Cohen Stuart and Jasper van der Gucht, Soft Matter, 2011, 7, 8281-8290.

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Three recently published Hot Articles

Read for free until 24 October…

Hot Review: This review summarizes recent developments in the field of self-assembly of non-linear polymers at the air/water interface, focusing on the influence of molecular architecture. Four classes of non-linear systems (polymer brushes, star-like polymers, dendritic polymers, and linear–dendritic polymers) are highlighted to elaborate their interfacial behaviors originating from different molecular architectures. Lei Zhao and Zhiqun Lin, Soft Matter, 2011, DOI: 10.1039/C1SM05745F.

Hot Paper: Researchers investigate the origin of the so-called magnetostriction effect (the deformation of a soft magnetic elastomer) in response to a uniform magnetic field. In particular the type of structural short-range order in the magnetic microparticle assembly is discussed. Oleg V. Stolbov, Yuriy L. Raikher and Maria Balasoiu, Soft Matter, 2011,  7, 8484-8487.

Hot Highlight: Helical assemblies from chiral block copolymers (BCPs*) have been intensively studied recently due to their unique hierarchical architectures arising from the interplay of various secondary interactions, and are discussed here in this Highlight Article. Yeo-Wan Chiang, Rong-Ming Ho, Christian Burger and Hirokazu Hasegawa, Soft Matter, 2011, DOI: 10.1039/C1SM05921A.

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Soft Matter poster prize winner: FLC 2011

Congratulations to Jason Morvan (Kent State University, USA) for winning the Soft Matter poster prize at the 13th International Conference on Ferroelectric Liquid Crystals.  

Jason Morvan’s winning poster was entitled “Electro-mechanical response of electro-spum polylactic acid fibers dispersed with ferroelectric barium titanate nanoparticles

 Jason Morvan with his winning poster

Jason Morvan with his winning poster

 Nélida Gimeno (Universidad de Zaragoza, Spain) won a Journal of Materials Chemistry poster prize for her poster “Liquid Crystalline Janus-type co-dendrimers based on bent-core units“.

The 13th International Conference on Ferroelectric Liquid Crystals was held 29th August  - 2nd September at Niagara Falls, Canada.

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Aspen Center for Physics 2012 Winter Conference on Biological Pattern Formation

We would like to bring to your attention the Aspen Center for Physics 2012 Winter Conference in Biological Physics, January 2-7, 2012: ”Growth and Form: Pattern Formation in Biology.” We have an exciting program planned, with a list of invited speakers that can be found at  the conference web page.

We encourage all those who are interested to submit an application.
The deadline for applications is October 15, with notifications to start November 1. Post-deadline applications will be considered only as space permits.

Please see the on-line application form . Limited financial support is available for junior participants.

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From hierarchical self-assemblies to biomimetics.

In a recent talk at the Physical Aspects of Polymer Science conference in the UK, Olli Ikkala discussed his work looking at the self-assembly of polymers and biopolymers.

The self-assembly of polymers is a powerful tool for creating or increasing the functionality of a material. Several different functionalities can often be combined in one material, which may also respond to external stimuli. The scale of the pattern required determines the material that should be used. For example surfactants and amphiphiles self-assemble with patterns on the 1-10nm scale, block copolymers on the 10-100nm scale and colloidal platelets or nanofibres form patterns >100nm. Examples of self-assembled functional materials include tuneable optically active materials, electrically conducting materials and porous materials for use as filters or catalysis templates.

But what if we want to do something more fancy and use biological materials to form structures? This is exactly what Ikkala has been doing, using nature as his inspiration. Examples in his talk included the self-assembly of diblock copolypeptides to form ‘woodpile’ like structures with well-defined lamellae spacing’s. Also discussed was the formation and assembly of cellulose nanofibres to form mechanically robust macrofibres. This was done via a wet extrusion process. The resulting materials have excellent mechanical properties. Using these nanocellulose fibres to form aerogels  and coating with titania dioxide results in materials with excellent oil absorbency. This was demonstrated in a nice video. Since the materials float on water and only absorb oil (no water), the materials could potentially be used to clean up oil spills.

Ikkala is also interested in using nanoclays to produce artificial nacre. The replication of nacre in the lab often involves time consuming, complex, energy intensive processes. The use of nanoclays enables lightweight nacre-mimetic films to be created in a roll-to-roll process. These materials have good strength and are very good heat shields. In a video played by Ikkala it was seen that a few mm of the nanoclay nacre was sufficient to protect silk, held on the other side, from damage by a 3000°C (?) heat torch. According to Ikkala: nanoclays are a “good approach to mimicking nacre, but the [material design] is not yet complete”. They do however “know exactly what they need to do” to iron out the problems.

Other work by Olli Ikkala, which may be of interested to Soft Matter readers includes:

Controlled growth of silver nanoparticle arrays guided by a self-assembled polymer-peptide conjugate, Soft Matter (2010).

Long and entangled native cellulose I nanofibres allow flexible aerogels and hierarchically porous templates for functionalities, Soft Matter (2008).

Tailoring of the hierarchical structure within electrospun fibres due to supramolecular comb-coil block copolymers, Soft Matter (2007).

Group photo of delegates at the conference. Olli Ikkala is on the front row, second from the left.

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Congratulations to the poster prize winners at Soft Matter Far From Equilibrium

Congratulations to Leopoldo Gomez (Leiden University, The Netherlands), Shashi Thutupalli (Max Planck Institute for Dynamics and Self-Organization, Germany) and Yusuke Maeda (The Rockefeller University, USA) for winning the Soft Matter poster prizes at the Gordon-Kenan Research Seminar 2011: Soft Matter Far From Equilibrium.

 The three poster prize winners at Soft Matter Far From Equilibrium

Left to right: Leopoldo Gomez, Shashi Thutupalli, Yusuke Maeda

The titles of the winning posters were:

  • Leopoldo Gomez “Shock Waves in Jammed Solids”
  • Shashi Thutupalli “Collective dynamics of swimming emulsions”
  • Yusuke Maeda “The Soret effect from molecular separation to nonequilibrium RNA world”

Soft Matter Far From Equilibrium was held at Colby-Sawyer College in New London, NH, USA, on Aug 13-14, 2011. Alexandra Zidovska, Harvard University, chaired the conference. We wish Leopoldo Gomez, Shashi Thutupalli, Yusuke Maeda and Alexandra Zidovska all the best for the future.

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Christos Likos appointed as new Soft Matter Associate Editor

I am delighted to announce that Professor Christos Likos, University of Vienna, has been appointed as an Associate Editor for Soft Matter.

Christos studied Electrical Engineering at the National Technical University of Athens, from which he graduated with a Diploma in 1988. He then joined the Department of Physics at Cornell, where he obtained his Ph.D. degree in 1993, working under the supervision of Neil Ashcroft on density functional theory of freezing and also collaborating with Chris Henley on problems of geometrical packing. He was Alexander von Humboldt Fellow at the University of Munich (1993-94), European Communities Fellow at the University of Trieste (1995-96), and Research Fellow at the Jülich Research Center (1997- 98), before joining the Department of Physics of the Heinrich Heine University of Düsseldorf, in which he obtained his Habilitation in Theoretical Physics in 2001. From 2002 to 2003 he was a Heisenberg Fellow of the German Research Foundation (DFG) at the University of Cambridge, Department of Theoretical Chemistry, before assuming a Professorship at the Department of Physics at the University of Düsseldorf in August 2003. He has held a visiting professorship at the University of Rome la Sapienza in 2005, as well as visiting scholar positions at Princeton and the University of Pennsylvania in 2006 and 2007. From 2007 to 2008, he was Senior Fellow of the Erwin Schrödinger Institute for Mathematical Physics in Vienna. As of June 2010, he is Professor (Multiscale Computational Physics) at the Faculty Physics of the University of Vienna.

Christos’ research interests revolve around coarse-graining, structure and dynamics of complex fluids, mainly solutions of colloidal particles and macromolecular aggregates. He is Coordinator of the EU-wide ITN “Physics of Complex Colloids: Equilibrium and Driven” (ITN-COMPLOIDS, http://www.itn-comploids.eu), a joint effort of leading laboratories to analyze the properties of complex fluids in- and out-of-equilibrium.

Christos joins our team of Soft Matter Associate Editors, Darrin Pochan and Lei Jiang. Choose to have your next high impact soft matter paper handled by one of our professional team of Editors in our Cambridge office or one of our Associate Editors by submitting online today!

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Physical Aspects of Polymer Science

This week saw the 25th biennial meeting of the UK’s Polymer Physics Group (PPG) take place at the University of Surrey. The PPG is part of the Institute of Physics and has strong ties with the Royal Society of Chemistry. This year celebrates the 25th meeting of the group and is also the 50th anniversary of the UK’s first ever meeting on the physics of polymers, which was held in Bristol in 1961. For those interested the proceedings of that first meeting were published in the British Journal of Applied Physics.

Along with a full oral and poster programme and invited talks from Olli Ikkala, Cait MacPhee, William Koros and Dieter Richter, a number of prizes were awarded at the conference. Prof. Tom McLeish from the University of Durham was awarded the Founders Prize. He is the sixth recipient of this award, which is given to a scientist who has made an outstanding contribution to Polymer Physics in the UK or Ireland.

Katherine Thomas (me!) was awarded the Students Prize for her paper on the non-equilibrium behaviour observed in thin polymer films published in Phys. Rev. E. This work looks at the interplay of the polymer film deposition procedure, the resulting non-equilibrium behaviour and the relaxation towards thermal equilibrium. A follow up paper to this work on the direct measurement of stresses in spin-cast films was recently published in Soft Matter. A previous post on this topic can be found here.

The exchange lecture with the American Physical Society Division of Polymer (DPoly) was given by Bradley Olsen. Proteins and enzymes are interesting materials for photovoltaics, catalysts and CO2 reduction and sequestration. Olsen is interested in incorporating proteins into materials so that they can be used in the above applications. He does this by forming protein-polymer diblock copolymers. These block copolymers can then be self-assembled enabling their structure to be easily controlled. His recent papers in Soft Matter can be found here and here.

The first place poster prize was awarded to Mike Smith at the University of Nottingham. Smith had three posters at the conference on ‘Optical properties of large amyloid spherulites’, ‘ Stretching dense colloidal suspensions: from flow to fracture’ and ‘Cracking in thin films of colloidal particles on elastomeric substrates’.

Congratulations to all the prize winners. The conference was very successful and highly enjoyable. It was one of the best conferences I have been to (and not just because they gave me a prize). I would highly recommend that those interested attend their next meeting in two years time.

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Top Ten most-read Soft Matter articles in July

This month sees the following articles in Soft Matter that are in the top ten most accessed in July:

Soft microorigami: self-folding polymer films
Leonid Ionov
Soft Matter, 2011, 7, 6786-6791
DOI:10.1039/c1sm05476g 

Biopolymers in nanopores: challenges and opportunities 
Hemant Kumar, Yves Lansac, Matthew A. Glaser and Prabal K. Maiti 
Soft Matter, 2011, 7, 5898-5907
DOI:10.1039/c0sm01517b 

Stimulus responsive nanogels for drug delivery 
Liusheng Zha, Brittany Banik and Frank Alexis
Soft Matter, 2011, 7, 5908-5916
DOI:10.1039/c0sm01307b 

Janus particles at an oil–water interface 
Bum Jun Park, Teresa Brugarolas and Daeyeon Lee 
Soft Matter, 2011, 7, 6413-6417 
DOI:10.1039/c1sm05460k 

Biomimetic morphogenesis of micropottery: helical coiling of mesostructured silica nanofibers 
Longping Zhou, Jianfeng Ye, Guosong Hong and Limin Qi 
Soft Matter, 2011, Advance Article 
DOI:10.1039/c1sm05593c 

Fabrication and evaluation of reduction-sensitive supramolecular hydrogel based on cyclodextrin/polymer inclusion for injectable drug-carrier application 
Jiahui Yu, Honglei Fan, Jin Huang and Jinghua Chen 
Soft Matter, 2011, 7, 7386-7394 
DOI:10.1039/c1sm05426k 

Bio-inspired anisotropic micro/nano-surface from a natural stamp: grasshopper wings 
Tong Zhang, Mingzhu Li, Bin Su, Changqing Ye, Kan Li, Weizhi Shen, Li Chen, Zhongxin Xue, Shutao Wang and Lei Jiang 
Soft Matter, 2011, 7, 7973-7975 
DOI:10.1039/c1sm05366c 

Self-assembly of double hydrophilic block copolymers in concentrated aqueous solution 
Adam Blanazs, Nicholas J. Warren, Andrew L. Lewis, Steven P. Armes and Anthony J. Ryan 
Soft Matter, 2011, 7, 6399-6403 
DOI:10.1039/c1sm05771e 

Mechanics of random fiber networks—a review 
R. C. Picu
Soft Matter, 2011, 7, 6768-6785 
DOI:10.1039/c1sm05022b 

Biomimetic microlens array with antireflective “moth-eye” surface 
Doo-Hyun Ko, John R. Tumbleston, Kevin J. Henderson, Larken E. Euliss, Joseph M. DeSimone, Rene Lopez and Edward T. Samulski 
Soft Matter, 2011, 7, 6404-6407 
DOI:10.1039/c1sm05302g 

Why not take a look at the articles today and blog your thoughts and comments below.

Fancy submitting an article to Soft Matter?  Then why not submit to us today or alternatively email us  your suggestions.

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Triblock copolymers—Yield stress fluids—Lipid rafts

Read for free until 30 September>>>

Amphiphilic triblock copolymers: A new study demonstrates that the length of a polyethylene glycol (PEG) spacer has a crucial impact on the association behaviour of temperature sensitive triblock copolymers at elevated temperatures. Findings show that a short PEG length promotes formation of interchain complexes at high temperatures. Atoosa Maleki, Kaizheng Zhu, Ramón Pamies, Ricardo Rodríguez Schmidt, Anna-Lena Kjøniksen, Göran Karlsson, José G. Hernández Cifre, José García de la Torre and Bo Nyström, Soft Matter, 2011, DOI: 10.1039/C1SM05679D

Yield stress fluids: Stress-induced fluidization of a simple yield stress fluid, namely a carbopol microgel, is addressed through extensive rheological measurements coupled to simultaneous temporally and spatially resolved velocimetry. A clear link between the transient regime of the fluidization process and the steady-state rheology is presented for the first time. Thibaut Divoux, Catherine Barentin and Sébastien Manneville, Soft Matter, 2011, DOI: 10.1039/C1SM05607G

Lipid rafts: Ligand-induced transbilayer coupling of rafts is simulated in this Hot Article. Using coarse grained molecular dynamics (CGMD) simulations the authors show that raft registration arises spontaneously in bilayers with a calcium- or ligand-crosslinked ordered phase segregating from a liquid disordered phase. Diego A. Pantano, Preston B. Moore, Michael L. Klein and Dennis E. Discher, Soft Matter, 2011, DOI: 10.1039/C1SM05490B

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