Supercooled liquids under shear: A mode-coupling theory approach

TL;DR

This paper extends mode-coupling theory to describe supercooled liquids under shear flow, predicting shear thinning and reduced relaxation times, aligning qualitatively with recent simulation results.

Contribution

It develops a generalized mode-coupling theory incorporating shear flow, applicable beyond linear response, for supercooled fluids.

Findings

Shear significantly reduces structural relaxation time.

Viscosity exhibits strong shear thinning behavior.

Results agree qualitatively with recent simulations.

Abstract

We generalize the mode-coupling theory of supercooled fluids to systems under stationary shear flow. Our starting point is the generalized fluctuating hydrodynamic equations with a convection term. The method is applied to a two dimensional colloidal suspension. The shear rate dependence of the intermediate scattering function and shear viscosity is analyzed. The results show a drastic reduction of the structural relaxation time due to shear and strong shear thinning behavior of the viscosity which are in qualitative agreement with recent simulations. The microscopic theory with minimal assumptions can explain the behavior far beyond the linear response regime.