Defect-Mediated Emulsification in Two Dimensions

TL;DR

This paper investigates how topological defects mediate emulsification in two-dimensional liquid dispersions with various symmetries, revealing universal interactions that stabilize emulsions and drive self-assembly.

Contribution

It introduces a universal droplet-droplet pair potential in 2D liquid dispersions with topological defects, explaining emulsion stabilization and self-assembly mechanisms.

Findings

Interaction is attractive at large distances and repulsive at short distances.

Preferred droplet separation and energy barriers to coalescence are quantified.

Thermal fluctuations and film thickness effects are discussed.

Abstract

We consider two dimensional dispersions of droplets of isotropic phase in a liquid with an XY-like order parameter, tilt, nematic, and hexatic symmetries being included. Strong anchoring boundary conditions are assumed. Textures for a single droplet and a pair of droplets are calculated and a universal droplet-droplet pair potential is obtained. The interaction of dispersed droplets via the ordered phase is attractive at large distances and repulsive at short distances, which results in a well defined preferred separation for two droplets and topological stabilization of the emulsion. This interaction also drives self-assembly into chains. Preferred separations and energy barriers to coalescence are calculated, and effects of thermal fluctuations and film thickness are discussed.