Phase Separation of Rigid-Rod Suspensions in Shear Flow

TL;DR

This paper investigates the phase behavior of rigid-rod suspensions under shear flow, using a modified Doi model to analyze phase coexistence, flow states, and shear banding phenomena.

Contribution

It introduces a modified Doi model to analyze phase separation and coexistence in rigid-rod suspensions under shear flow conditions.

Findings

Identification of phase coexistence diagrams for different flow states

Calculation of effective constitutive relations during phase separation

Discovery of a wide range of phase behaviors including shear banding

Abstract

We analyze the behavior of a suspension of rigid rod-like particles in shear flow using a modified version of the Doi model, and construct diagrams for phase coexistence under conditions of constant imposed stress and constant imposed strain rate, among paranematic, flow-aligning nematic, and log-rolling nematic states. We calculate the effective constitutive relations that would be measured through the regime of phase separation into shear bands. We calculate phase coexistence by examining the stability of interfacial steady states and find a wide range of possible ``phase'' behaviors.