Soft Matter Blog

The elastic response of active biopolymer networks is determined not only by molecular motors but also by the density and stiffness of crosslinking proteins say US Scientists.

Peng Chen and Vivek B. Shenoy from Brown University, USA, studied the elastic response of actin networks with both compliant and rigid crosslinks by modeling molecular motors as force dipoles.

Fancy knowing more? Read the full article for free here: Peng Chen and Vivek B. Shenoy, Soft Matter, 2011, DOI:10.1039/C0SM00908C

A robust micro-porous 3D polymeric film has been constructed using a sacrificial template by Chinese scientists. This simple and cheap method has a variety of promising applications including biosensors, liquid chromatography and micro-reactors the team say.

The team led by Lei Li at Xiamen University and Zhi Ma at Shanghai Institute of Organic Chemistry demonstrated that commercially available triblock polymers can perfectly contour nonplanar substrates with hierarchical micro-structures, despite the sharp corners and shapes. This robust strategy is ascribed to the fluid-like property of the rubber matrix of the polymers. In the sequent vulcanization, the resultant 3D structures are effectively cross-linked and become self-supported with improved thermal stability and solvent resistance.

Why not read the full article for free here:

Lei Li, Yawen Zhong, Jianliang Gong, Jian Li, Caikang Chen, Birong Zeng and Zhi Ma, Soft Matter, 2011, DOI: 10.1039/C0SM00809E

Nanobubbles: what do we know and how can we understand their surprising stability and morphology?

In this Tutorial Review Vincent Craig discusses the nanobubble puzzle. Nanobubbles are thought to play a role in the rupture of thin films during froth flotation, hydrodynamic slip over surfaces, interaction forces between hydrophobic surfaces and influence the electroplating and electrolysis processes. Craig covers what is known of nanobubbles and discuss the challenges in understanding nanobubble morphology and stability.

Read the full the full article for free here: Vincent Stuart James Craig, Soft Matter, 2011, DOI:10.1039/C0SM00558D

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In the tightly packed molecular world of the cell DNA is protected and wrapped up into small packages called chromatins. The complex plays a crucial role in living organisms because its dynamic organization is a key factor for controlling the regulation of gene expression.

To investigate the unwrapping process Qianqian Cao and coworkers at Jilin University, China, used coarse-grained molecular dynamics simulations to study the unwinding of a DNA-nanosphere complex when a force exerted on the DNA chain.

The team found that the wrapping degree and the folding state of DNA around the sphere is significantly dependent on the surface charge density and the salt concentration. When an external force is applied to two ends of DNA chain, different stages are observed in the stretching process as the complex is unwrapped. The team say that this behaviour also has been observed in experiments and other simulations on the stretching of chromatin.

Read Cao’s full article for free in Soft Matter here:  Qianqian Cao, Chuncheng Zuo, Yanhong Ma, Lujuan Li and Zhou Zhang, Soft Matter, 2011, DOI:10.1039/C0SM00512F

Have you ever wondered what’s going on in a foam when it flows? In her latest Soft Matter paper, Isabelle Cantat at the Université Rennes, France, simulates the dissipation of bubbles in foam. Cantat used 2D numerical simulations involving 500 bubbles under simple shear, in a non-quasi static regime to study the dissipation of bubbles.

Cantat shows that small tension dynamical inhomogeneities induce foam structure modifications responsible for the largest part of the stress increase. The stress increase with increasing shear rate is mainly due to increasing bubble elongation that can be interpreted as an increase of the plastic threshold.

Interested to know more? Read Cantat’s Soft Matter paper here: