Phase Separation Driven by Active Flows

TL;DR

This paper develops a continuum model for active nematic and isotropic fluid mixtures, revealing micro-phase separation driven by active flows and anchoring, with implications for biological processes like cell-sorting.

Contribution

It introduces a two-fluid continuum theory incorporating active flows and demonstrates micro-phase separation due to active anchoring and concentration gradients.

Findings

Micro-phase separation observed in active nematic-isotropic mixtures

Active flows driven by concentration gradients cause phase separation

Model may explain biological phenomena like cell-sorting

Abstract

We extend the continuum theories of active nematohydrodynamics to model a two-fluid mixture with separate velocity fields for each fluid component, coupled through a viscous drag. The model is used to study an active nematic fluid, mixed with an isotropic fluid. We find micro-phase separation, and argue that this results from an interplay between active anchoring and active flows driven by concentration gradients. The results may be relevant to cell-sorting and the formation of lipid rafts in cell membranes.