Soft Matter more green

Most of our everyday materials are made out of synthetic compounds that are known to have a negative environmental impact and therefore need to be replaced. Soft Matter sciences are ideally placed to address these issues. We aim with this EU-funded FORGREENSOFT project to explore new routes to replace some of these ingredients. The focus is on bio-sourced raw materials obtained through eco-friendly processes. We will achieve this through a multilevel transfer of knowledge and research collaboration between FORTH and European centers of excellence at the University of Vienna in Austria and at the Max-Planck Institute in Germany.


2nd Short Course

19 - 21 MAY 2024
FORTH, Heraklion, GREECE

Visit from FORTH to UNIVIE Thanasis Athanasiou

24 FEBRUARY 2024
UNIVIE, Vienna, Austria

Meeting FORTH and MPG-P

22 FEBRUARY 2024



Residual stresses in colloidal gels*

A combination of experiments and Brownian Dynamics (BD) simulations is utilized to examine internal stresses in colloidal gels brought to rest from steady shear at different shear rates. A model colloidal gel with intermediate volume fraction is chosen where attractions between particles are introduced by adding non-adsorbing linear polymer chains. After flow cessation, the gel releases the stress in two distinct patterns: at high shear rates, where shear forces dominate over attractive forces, the shear-melted gel behaves as a liquid and releases stresses to zero after flow cessation. After low shear rates, though, stresses relax only partially, similar to the response of hard sphere glasses and jammed soft particles. The balance between shear and attractive forces which determines the intensity of structural distortion controls the amplitude of the residual stresses through a universal scaling. Stress decomposition to repulsive and attractive contributions in BD simulations reveals that internal stresses mainly originate from attractive forces. Moreover, analysis of particle dynamics indicates that internal stresses are associated with sub-diffusive particle displacements on average smaller than the attraction range as such short-range displacements are not sufficient to completely erase structural anisotropy caused during the course of shear.


* Publication relevant to FORGREENSOFT, published before the start of the project"