Coexistence and Phase Separation in Sheared Complex Fluids

TL;DR

This paper develops a method to construct dynamic phase diagrams for complex fluids under shear, revealing how phase coexistence and separation depend on flow conditions, with a focus on lyotropic nematic liquid crystals.

Contribution

It introduces a general approach to analyze flow-induced phase transitions in complex fluids using a steady interface criterion, applicable beyond the specific model studied.

Findings

Dynamic phase diagrams for sheared complex fluids are constructed.

The method applies to various systems with non-local effects.

Insights into phase coexistence under flow conditions are provided.

Abstract

We demonstrate how to construct dynamic phase diagrams for complex fluids that undergo transitions under flow, in which the conserved composition variable and the broken-symmetry order parameter (nematic, smectic, crystalline, etc.) are coupled to shear rate. Our construction relies on a selection criterion, the existence of a steady interface connecting two stable homogeneous states. We use the (generalized) Doi model of lyotropic nematic liquid crystals as a model system, but the method can be easily applied to other systems, provided non-local effects are included.