Caddisfly silk gets shocked into self-recovery

Article written by Emma Stephen

The tough, extendable, energy-dissipating properties of the casemaker caddisfly’s adhesive silk are down to a self-recovering network of calcium crosslinks, new research shows. US researchers behind the discovery hope to harness these findings to design new synthetic bioadhesives that can adhere to wet tissues.

Images (l and m) of silk holding together glass beads in the same way that silk and stones combine to make the body armour (r)

To read the full article visit Chemistry World.

Self-recovering caddisfly silk: energy dissipating, Ca2+-dependent, double dynamic network fibers
Nicholas N. Ashton and Russell J. Stewart  
Soft Matter, 2015, Advance Article
DOI: 10.1039/C4SM02435D, Paper

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Joint Biomaterials Science and Soft Matter ‘Silk and silk-inspired materials’ Web Collection

Take a look at the ‘Silk and silk-inspired materials’ web collection, a joint venture by Biomaterials Science and Soft Matter.

Are you interested in why spider silk is so strong? Or maybe you’re intrigued to find out how silk can be utilised in cell delivery? Whatever your curiosity be sure to check out the ‘Silk and silk-inspired materials’ web collection and find out why this growing area of research is proving so popular!

The web collection features articles from both Biomaterials Science and Soft Matter by leading authors from around the world. The collection contains a range of article types which cover the properties and rheology of silk-inspired materials as well as investigations into the surface properties of spider silk particles. Please follow the link to read all the articles in this popular area of research.

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Soft Matter Lectureship: Nominations now open

Do you know someone who deserves recognition for their contribution to the soft matter field?

Now is your chance to propose they receive the accolade they deserve.

Soft Matter is pleased to announce that nominations are now being accepted for its Soft Matter Lectureship 2015. This annual lectureship was established in 2009 to honour an early-stage career scientist who has made a significant contribution to the soft matter field.

Previous winners include:

Eric Dufresne                                            Eric Furst                                                 Patrick Doyle


2014 - Eric Dufresne, based at Yale Univeristy, USA

2013 - Eric Furst, from the University of Delaware, USA

2012 - Patrick Doyle, based at MIT, USA

2011 – Michael J. Solomon, from the University of Michigan, USA

2010 – Bartosz Grzybowski, based at Northwestern University, USA

2009 – Emanuela Zaccarelli, from Sapienza University of Rome, Italy

Qualification

To be eligible for the Soft Matter Lectureship, the candidate should be in the earlier stages of their scientific career, typically within 15 years of attaining their doctorate or equivalent degree, and will have made a significant contribution to the field.

Description

The recipient of the award will be asked to present a lecture three times, one of which will be located in the home country of the recipient. The Soft Matter Editorial Office will provide the sum of £1000 to the recipient for travel and accommodation costs.

The award recipient will be presented with the award at one of the three award lectures. They will also be asked to contribute a lead article to the journal and will have their work showcased on the back cover of the issue in which their article is published.

Selection

The recipient of the award will be selected and endorsed by the Soft Matter Editorial Board.

Nominations

Those wishing to make a nomination should send details of the nominee, including a brief C.V. (no longer than 2 pages A4) together with a letter (no longer than 2 pages A4) supporting the nomination, to the Soft Matter Editorial Office by 6th March 2015.  Self-nomination is not permitted.

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Soft Matter Welcomes New Associate Editor Dimitris Vlassopoulos

We are delighted to welcome our newest Soft Matter Associate Editor: Professor Dimitris Vlassopoulos (University of Crete, Greece).

Dimitris is a leading expert in polymer rheology and has published over 160 papers. His research focuses on soft matter physics and engineering problems with specific interests in molecular rheology and rheo-physics in the bulk and at liquid interfaces, architecturally complex polymers, and soft colloids.

Dimitris also brings a wealth of previous editorial experience to the Soft Matter team; we are delighted to have him board.

To find out more about Dimitris’ research, take a look at this recent paper:

Molecular rheology of branched polymers: decoding and exploring the role of architectural dispersity through a synergy of anionic synthesis, interaction chromatography, rheometry and modeling
Evelyn van Ruymbeke, Hyojoon Lee, Taihyun Chang, Anastasia Nikopoulou, Nikos Hadjichristidis, Frank Snijkers, Dimitris Vlassopoulos

And a Soft Matter issue dedicated to the theme of ‘Bridging the gap between soft and hard colloids’ of which Dimtris was a Guest Editor along with Professor Michel Cloitre

As a Soft Matter Associate Editor, Dimitris will be handling submissions to the journal. Why not submit your next paper to his Editorial Office?
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HOT articles for January!

Graphene oxide single sheets as substrates for high resolution cryoTEM
Marcel W. P. van de Put, Joseph P. Patterson, Paul H. H. Bomans, Neil R. Wilson, Heiner Friedrich, Rolf A. T. M. van Benthem, Gijsbertus de With, Rachel K. O’Reilly and Nico A. J. M. Sommerdijk

Graphical abstract: Graphene oxide single sheets as substrates for high resolution cryoTEM

Cell membrane wrapping of a spherical thin elastic shell
Xin Yi and Huajian Gao

Graphical abstract: Cell membrane wrapping of a spherical thin elastic shell

 

These articles will be free until 3rd February 2015


A Master equation for the probability distribution functions of forces in soft particle packings
Kuniyasu Saitoh, Vanessa Magnanimo and Stefan Luding

Graphical abstract: A Master equation for the probability distribution functions of forces in soft particle packings

Structural tailoring of hydrogen-bonded poly(acrylic acid)/poly(ethylene oxide) multilayer thin films for reduced gas permeability
Fangming Xiang, Sarah M. Ward, Tara M. Givens and Jaime C. Grunlan

Graphical abstract: Structural tailoring of hydrogen-bonded poly(acrylic acid)/poly(ethylene oxide) multilayer thin films for reduced gas permeability

These articles will be free until 10th February 2015


Smectic layer instabilities in liquid crystals
Ingo Dierking, Michel Mitov and Mikhail A. Osipov

Graphical abstract: Smectic layer instabilities in liquid crystals

 
Graphical abstract: Coarse-grained simulation of dynamin-mediated fission
 
 
 These articles will be free until 17th February 2015Self-recovering caddisfly silk: energy dissipating, Ca2+-dependent, double dynamic network fibers
Nicholas N. Ashton and Russell J. Stewart   

Graphical abstract: Self-recovering caddisfly silk: energy dissipating, Ca2+-dependent, double dynamic network fibers
Structure and percolation of one-patch spherocylinders
Cheng-yu Zhang, Xing-liang Jian and Wei Lu   

Graphical abstract: Structure and percolation of one-patch spherocylinders

These articles will be free until 24th February 2015


 


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Leading Article by Soft Matter 2014 Lectureship Winner

New article by the Soft Matter 2014 Lectureship winner, Eric Dufresne.

Surface tension and the mechanics of liquid inclusions in compliant solids

Robert W. Style, John S. Wettlaufer, and Eric R. Dufresne

Dufresne et al. graphical abstract

This article proposes a theory of fluid inclusions in soft solids and builds upon experimental findings of a previous paper recently published in Nature Physics – “Stiffening solids with liquid inclusions” doi:10.1038/nphys3181 – which revealed that Eshelby’s foundational theory fails to describe the mechanical response of soft composites. Eshelby’s theory of elastic inclusions is significantly cited and outlines the response of microscopic inclusions within an elastic solid when macroscopically stress is applied. Furthermore, Eshelby’s theory allows the prediction of bulk properties and is fundamental in calculating the stress field in fracture mechanics. It has been widely used in many other areas such as cell biology to predict cell interactions and seismology.

The theoretical study aims to rationalise the experimental results from the previous paper and explain that they were due to the surface tension of the solid-liquid interface, which is completely ignored in established theory.

The work expands previous theories based on strain-dependent surface stresses, relevant to nanoinclusions in stiffer materials, but not for softer materials such as gels.

The group adapted Eshelby’s inclusion theory so that it included surface tension for liquid inclusions in a linear elastic solid, giving both the microscopic behaviour and the macroscopic effects of inclusions in composites. The authors believe that these findings can be applied to a wide variety of soft material systems, especially composites comprising of soft materials such as gels and elastomers.

Full citation information:

Surface tension and the mechanics of liquid inclusions in compliant solids
Robert W. Style, John S. Wettlaufer and Eric R. Dufresne
Soft Matter, 2015, Advance Article
DOI: 10.1039/C4SM02413C

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HOT articles for December!

Pearling and arching instabilities of a granular suspension on a super-absorbing surface
Julien Chopin and Arshad Kudrolli

Graphical abstract: Pearling and arching instabilities of a granular suspension on a super-absorbing surface

Effects of topological constraints on globular polymers
Maxim V. Imakaev, Konstantin M. Tchourine, Sergei K. Nechaev and Leonid A. Mirny

Graphical abstract: Effects of topological constraints on globular polymers

These articles will be free until 7th January 2015


Thermodynamics of the self-assembly of non-ionic chromonic molecules using atomistic simulations. The case of TP6EO2M in aqueous solution
Anna Akinshina, Martin Walker, Mark R. Wilson, Gordon J. T. Tiddy, Andrew J. Masters and Paola Carbone

Graphical abstract: Thermodynamics of the self-assembly of non-ionic chromonic molecules using atomistic simulations. The case of TP6EO2M in aqueous solution

Graphene Oxide Single Sheets as Substrate for High Resolution cryoTEM
Marcel van de Put, Joseph P. Patterson, Paul Bomans, Neil Wilson, Heiner Friedrich, Rolf van Benthem, Gijsbertus de With, Rachel K. O’Reilly and Nico Sommerdijk 

These articles will be free until 14th January 2015


Surface tension and the mechanics of liquid inclusions in compliant solids
Robert W. Style, John S. Wettlaufer and Eric R. Dufresne

Graphical abstract: Surface tension and the mechanics of liquid inclusions in compliant solids

Observation of dynamical heterogeneities and their time-evolution on the surface of an amorphous polymer
Hung Kim Nguyen, Dong Wang, Thomas P Russell and Ken Nakajima

These articles will be free until 20th  January 2015


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Take 1…minute for chemistry in health

Can you explain the importance of chemistry to human health in just 1 minute? If you’re an early-career researcher who is up to the challenge, making a 1 minute video could win you £500.

The chemical sciences will be fundamental in helping us meet the healthcare challenges of the future, and we are committed to ensuring that they contribute to their full potential. As part of our work in this area, we are inviting undergraduate and PhD students, post-docs and those starting out their career in industry to produce an original video that demonstrates the importance of chemistry in health.Take 1... minute for chemistry in health

We are looking for imaginative ways of showcasing how chemistry helps us address healthcare challenges. Your video should be no longer than 1 minute, and you can use any approach you like.

The winner will receive a £500 cash prize, with a £250 prize for second place and £150 prize for third place up for grabs too.

Stuck for inspiration? Last year’s winning video is a good place to start. John Gleeson’s video was selected based on the effective use of language, dynamic style, creativity and its accurate content.

The closing date for entries to be submitted is 30 January 2015. Our judging panel will select the top five videos. We will then publish the shortlisted videos online and open the judging to the public to determine the winner and the runners up.

For more details on how to enter the competition and who is eligible, join us at the Take 1… page.

Good luck!

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A simple route to responsive, particle-stabilized foams using bare silica nanoparticles

Web writer Rob Woodward highlights a hot article from the journal


Defined as bubbles of gas in liquid-film matrix, foams are important precursors in the food and cosmetic industry and for the production of macroporous materials. In this report a simple, effective route to silica nanoparticle stabilised responsive aqueous foams has been demonstrated by the Binks group. Stimuli-responsive surface active particles have generated growing interest in recent years, utilising triggers including pH, temperature and light irradiation to create ‘switchable’ foams, i.e. the ability to “switch-off” the foaming capability of the particles. However, the production of responsive surface active particles usually involves surface coating of mineral particles or the complicated synthesis of functional polymer particles.

In order to address this problem Binks et al. utilise the interaction of N’-dodecyl-N,N-dimethylacetamidinium bicarbonate, a responsive surfactant, with anionic silica nanoparticles in water. By exposure to either CO2 or N2 the responsive surfactant can be switched between a cationic species and a surface-inactive neural form, respectively. On the formation of the cationic species, complexation of the surfactant to anionic silica nanoparticle surfaces gives an in situ increase in the hydrophobicity of the silica, yielding surface-active nanoparticles. Agitation of the resulting complexed system gives foams, however, on exposure to N2 the responsive surfactant returns to its neutral state and desorbs from the surface of the silica particles, resulting in desorption of the particles from the water-air interface.

This simple route to switchable particle-stabilized aqueous foams removes the need for the complicated synthesis of particles as ‘bare’ silica nanoparticles can be used. The synergistic effect of the responsive surfactant and the nanoparticles also allows for the production of foams using a much lower concentration of surfactant than in a responsive-surfactant system alone.

Micrographs of the bubbles in foams produced by shaking 10 cm3 of a dispersion of 0.5 wt% particles in a surfactant solution at different concentrations in bottles (25 cm3) taken immediately after shaking. Surfactant concentrations from A to F are: 0.1, 0.2, 0.3, 0.6, 1.0 and 2.0 mM.

To find out more read the full article:

Responsive aqueous foams stabilised by silica nanoparticles hydrophobised in situ with a switchable surfactant

Yue Zhu, Jianzhong Jiang, Zhenggang Cui and Bernie Binks

Soft Matter, 2014, Accepted Manuscript

DOI: 10.1039/C4SM01970A

This post was written by web writer Rob Woodward. Rob is currently based in Imperial College London working in the Polymer and Composite Engineering (PaCE) group. Rob has a background in both responsive polymeric surfactants and microporous organic polymers for carbon capture and storage.

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On polydispersity and the hard sphere glass transition – an overview of a hot article

On polydispersity and the hard sphere glass transition, Emanuela Zaccarelli, Siobhan M. Liddle and Wilson C. K. Poon, Soft Matter, 2014

DOI: 10.1039/C4SM02321H

The aim of this work was to investigate the dynamics of polydisperse hard spheres at high packing fractions φ. The effects of polydispersity and the detailed shape of the particle size distribution (PSD) were studied.


The glass transition is not fully understood despite many decades of research. The discovery that hard-spheres, sterically-stabilised polymethylmethacrylate (PMMA) colloids, underwent kinetic arrest at a packing fraction of φ = φg ≈ 0.58 led to hard sphere colloids becoming the preferred method to test mode coupling theory (MCT). This is a significant piece of work by Emanuela Zaccarelli, Siobhan M. Liddle and Wilson C. K. Poon who are the first to present simulations of a polydisperse system of hard spheres with a size distribution essentially identical to the experimental data. The findings of the authors are novel and very important, they also put forward a new interpretation of what is going on in glass transition of MCT experiments. Assumptions with regard to PSD are not made and a model as close to the experimental one as possible is designed.

Event-driven Molecular Dynamics (MD) simulations of hard spheres with different PSD were performed. Experimentally obtained PSD from ≈ 2200 PMMA particles were measured by transmission electron microscopy (TEM). N = 2309 particles were simulated with the experimental PSD, measurement noise was included to produce a realistic system representation. N = 2000 particles taken from Gaussian and top hat distributions were considered for comparison.

It was found that a mixed state of ergodic small particles and glassy large particles in a window of concentrations is present and results in a hybrid dynamical state that is fluid for a long time but shows an unusual type of ageing. The breakdown of the MCT-predictions is due to the existence of partial decoupling, which is not accounted for in the monodisperse-version of MCT. However, the results of MCT are recovered once the polydispersity is reduced. There is a non-monotonic dependence of the quality of the glass former on the polydispersity index, s. When s = 0, the system is prone to crystallization and strong glasses are formed when s = <8%. The glass transition is smeared out due to the emergence of the “ageing liquid” for higher values of s as well as for samples drawn from peaked distributions. The precise form of the size distribution is relevant, a peaked distribution that allows a distinction between small and large particles is essential but this is not the case in the top hat particle distribution.

In conclusion, at a fixed relative standard deviation of the PSD the exact shape of the PSD has little influence on the general behaviour of the dynamics, large differences between the dynamics of “small” and “large” particles are found for realistic PSD shapes.

The glass transition is smeared out in polydisperse hard spheres due to decoupling between small and large particles

Please follow the link for the full article.

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