Author Archive

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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Take 1…minute for chemistry in health

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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