Colloid-stabilized emulsions: behaviour as the interfacial tension is reduced

TL;DR

This study investigates particle-stabilized emulsions with tunable interfacial tension near the critical solution temperature, revealing how interface elasticity influences emulsion stability and behavior.

Contribution

It introduces a novel method to create and analyze particle-stabilized emulsions with temperature-dependent interfacial tension, highlighting the role of interface elasticity.

Findings

Interfacial tension decreases as temperature approaches the critical point.

Interface elasticity significantly affects emulsion stability and deformation.

Crumpling and coalescence occur as interfacial tension reduces.

Abstract

We present confocal microscopy studies of novel particle-stabilized emulsions. The novelty arises because the immiscible fluids have an accessible upper critical solution temperature. The emulsions have been created by beginning with particles dispersed in the single-fluid phase. On cooling, regions of the minority phase nucleate. While coarsening these nuclei become coated with particles due to the associated reduction in interfacial energy. The resulting emulsion is arrested, and the particle-coated interfaces have intriguing properties. Having made use of the binary-fluid phase diagram to create the emulsion we then make use of it to study the properties of the interfaces. As the emulsion is re-heated toward the single-fluid phase the interfacial tension falls and the volume of the dispersed phase drops. Crumpling, fracture or coalescence can follow. The results show that the elasticity of the interfaces has a controlling influence over the emulsion behaviour.