Phase separation around heated colloid in bulk and under confinement

TL;DR

This paper investigates how a temperature gradient influences the non-equilibrium phase separation of a binary liquid around a heated colloid, considering effects of surface properties and confinement on coarsening dynamics.

Contribution

It introduces a detailed analysis of temperature-gradient-induced coarsening near colloids and under confinement, highlighting the impact on morphology and segregation speed.

Findings

Temperature gradients modify coarsening patterns compared to uniform temperature.

Surface adsorption properties significantly influence local phase separation.

Confinement accelerates phase segregation and promotes bridge formation.

Abstract

We study the non-equilibrium coarsening dynamics of a binary liquid solvent around a colloidal particle in a presence of a time-dependent temperature gradient that emerges after temperature quench of a suitably coated colloid surface. The solvent is maintained at its critical concentration and the colloid is fixed in space. The coarsening patterns near the surface are shown to be strongly dependent on the colloid surface adsorption properties and on the temperature evolution. The temperature gradient alters the morphology of a binary solvent near the surface of a colloid as compared to the coarsening proceeding at constant temperature everywhere. We also present results for the evolution of coarsening in thin films with confining surfaces preferring one species of the binary liquid mixture over the other. Confinement leads to a faster phase segregation process and formation of a bridge connecting the colloid and both the confining walls.