Thermodynamics predicts a stable microdroplet phase in polymer-gel mixtures undergoing elastic phase separation

TL;DR

This paper demonstrates how elastic interactions in gel-polymer mixtures can stabilize a microdroplet phase during phase separation, with thermodynamics predicting droplet sizes based on material properties.

Contribution

It introduces a mean-field thermodynamic framework to analyze droplet stabilization and size in elastic gel-polymer mixtures, highlighting elastic effects on phase behavior.

Findings

Elastic interactions stabilize multiple droplets.

Droplet size depends on interfacial tension, Flory parameter, and elastic moduli.

Elastic effects influence phase separation in biopolymers.

Abstract

We study the thermodynamics of binary mixtures with the volume fraction of the minority component less than the amount required to form a flat interface and show that the surface tension dominated equilibrium phase of the mixture forms a single macroscopic droplet. Elastic interactions in gel-polymer mixtures stabilize a phase with multiple droplets. Using a mean-field free energy we compute the droplet size as a function of the interfacial tension, Flory parameter, and elastic moduli of the gel. Our results illustrate the role of elastic interactions in dictating the phase behavior of biopolymers undergoing liquid-liquid phase separation.