Stress-induced solidification in colloidal suspensions

Abstract

I review recent work on the idea that jamming of colloidal suspensions under shear can be viewed as a stress-induced glass transition. A schematic model, incorporating ideas from mode coupling theory but entirely neglecting hydrodynamic interactions, admits in certain parameter ranges an extreme shear-thickening material that is flowable at low stresses but which seizes up above a certain threshold of order the Brownian stress scale. The jammed material can be brittle in the sense that it will fracture, not shear-melt, at still higher stresses. This scenario can be used to explain some bizarre experimental findings concerning the process of 'granulation', whereby a small volume of colloidal suspension can bistably exist in one of two states, a solid granule and a flowable droplet.