Transient stress evolution in repulsion and attraction dominated glasses

TL;DR

This paper uses microscopic mode coupling theory to analyze how stress evolves in colloidal glasses under shear, focusing on the effects of packing and attractions, and compares predictions with experimental data.

Contribution

It extends mode coupling theory to include shear in colloidal dispersions, providing insights into stress evolution near glass transitions with and without attractions.

Findings

Stress-strain behavior modeled successfully

Effects of attractions on stress response analyzed

Theoretical results align with experimental observations

Abstract

We present results from microscopic mode coupling theory generalized to colloidal dispersions under shear in an integration-through-transients formalism. Stress-strain curves in start-up shear, flow curves, and normal stresses are calculated with the equilibrium static structure factor as only input. Hard spheres close to their glass transition are considered, as are hard spheres with a short-ranged square-well attraction at their attraction dominated glass transition. The consequences of steric packing and physical bond formation on the linear elastic response, the stress release during yielding, and the steady plastic flow are discussed and compared to experimental data from concentrated model dispersions.