Soft Matter Blog

Inspired by the fluid-like motion of flocks of birds, researchers in the US have used techniques from soft matter physics to study the way that fire ants move.

At high density collective ant flow can be described by the physics of glass-forming soft materials © Shutterstock

Collective motion is ubiquitous in nature. Fire ants in particular provide a fascinating case study due to the confinement enforced by the foraging tunnels in which they move. A key factor in the motion of fire ants, and other eusocial insects, is the requirement to stop and communicate with each other, leading to traffic jams and blockages along the 50m long underground superhighways in which they travel.

To read the full article visit Chemistry World.

Glass-like dynamics in confined and congested ant traffic
Nick Gravish, Gregory Gold, Andrew Zangwill, Michael A.D. Goodisman and Daniel I Goldman  
Soft Matter, 2015, Accepted Manuscript
DOI: 10.1039/C5SM00693G, Paper

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

Researchers in Spain are taking steps towards ‘allergy-free’ food, by treating allergy-inducing proteins with a pulsed light treatment that makes them easier to digest.

 The scientists at the University of Granada and the AZTI-Tecnalia Food Research Institute studied the protein β-lactoglobulin, which acts as an excellent emulsifier in milk and other food products but has a compact structure that defies easy digestion. This lack of digestibility is linked to allergenicity, explains team member Julia Maldonado-Valderrama: ‘If the protein is not completely digested, the body reacts as if it is an allergen, which can trigger an allergic reaction.’ Pre-treatment could break down the protein structure before eating; however, it’s a balancing act. ‘If you break the protein down too much in order to facilitate digestion, they lose their functionality and can’t be used to make foams and emulsions in food products,’ says Maldonado-Valderrama.

To read the full article please visit Chemistry World.

Improved digestibility of β-lactoglobulin by pulsed light processing: dilatational and shear study
Teresa del Castillo-Santaella, Esther Sanmartín-Sierra, Miguel Cabrerizo-Vílchez, J Arboleya and Julia Maldonado-Valderrama 
Soft Matter, 2014
DOI: 10.1039/C4SM01667J, Paper

Researchers have devised a new method to transport micro cargo – by attaching it to chains of colloidal particles that wiggle their way through liquid crystals.

The research team, led by Hiroshi Orihara from Hokkaido University, Japan, and Christian Bahr from the Max Planck Institute for Dynamics and Self-Organization, Germany, created colloidal ‘caterpillars’ from surface-modified silica particles which self-assemble into chains when placed in a liquid crystal medium. To make them move, the team exploit an effect called electrohydrodynamic convection (EHC), where the application of an electric field creates a convective pattern of parallel rolls within the medium. The caterpillars travel in an undulating motion across successive rolls, driven by a combination of hydrodynamic flow and electric field effects. Excitingly, the caterpillars can be attached to and used to transport larger particles and liquid droplets, which are in themselves too big to be moved by the EHC rolls.

To read the full article visit Chemistry World.

Already used in everything from paints to optical materials, colloids have found an entirely new application: as computing elements capable of high density information storage.

US collaborators Sharon Glotzer from University of Michigan and David Pine from New York University have designed a system of reconfigurable colloidal clusters which show potential for performing computational functions in unconventional environments. The team’s ‘digital colloids’ are based on specially designed dimpled particles, which, through entropic interactions, can be made to assemble onto a central sphere and explore various configurations on the sphere’s surface.

To read the full article please visit Chemistry World.

Measurements highlighting the different mechanical properties of healthy and diseased tear film could provide fresh understanding of the underlying causes of dry eye syndrome, and point to new treatments to ease the discomfort of millions of sufferers.

With risk factors including contact lens wear and extended periods in front of a computer screen, the discomfort and visual disturbance associated with dry eye syndrome (DES) is a growing public health concern.

To read the full article please visit Chemistry World.

The secret to soft skin is not necessarily increasing its water content but retaining molecular fluidity © Shutterstock

Scientists in Sweden have probed the outermost layer of skin to gain molecular insights into how naturally occurring molecules in this layer protect it from drying out.

Healthy skin with a normal degree of hydration is soft and pliable. This is not the case for dry skin, which is brittle and easily cracks. To treat dry skin it is common to apply a cosmetic containing a humectant  ̶  a type of “moisturiser” – like glycerol or urea. These substances are also components of natural moisturising factor (NMF), a group of molecules naturally present in the skin barrier. The beneficial function of these compounds if often claimed to be their capacity for increasing skin hydration, although the underlying mechanisms are generally described with a rather weak molecular basis.

We encounter gels on a daily basis in food, cosmetics and pharmaceuticals. Some gels are very responsive – something can happen to them and they will break down. Some gels are very robust and can survive a lot of stress. Often when a responsive gel responds to a stimulus it breaks down so it is no longer a gel you can do anything with. ‘That’s useful in itself, but you don’t always want that,’ says David Smith whose team at the University of York have developed the new responsive and robust gel. 

One gel network can be assembled and responsively disassembled while the other polymer retains the material’s integrity

Interested to know more? Read the full news article by Jennifer Newton in Chemistry World here…

Read the article by  D J Cornwell, B O Okesola and D K Smith in Soft Matter: