Re-entrant ordering of solute in a colloidal suspension during solvent evaporation

TL;DR

This paper investigates the self-assembly and re-entrant ordering behavior of silica micro-spheres during solvent evaporation, revealing how dynamics slow down near a glass transition and how experimental conditions influence ordering.

Contribution

It demonstrates the re-entrant ordering phenomenon in colloidal suspensions during evaporation, supported by experiments, simulations, and phenomenological theory, highlighting the interplay of ordering and compaction.

Findings

Re-entrant order-disorder phase diagram as a function of particle density and drying time.

Experimental conditions can be tuned to minimize competing phenomena.

Theoretical and simulation models explain the observed re-entrant behavior.

Abstract

We study the phenomenon of self-assembly of silica micro-spheres on a glass plate during evaporation of the solvent from a colloidal suspension. Our experiments unveil an interesting competition between ordering and compaction in a strongly driven, out of equilibrium system arising from a slowing down of dynamics due to an impending glass transition. A suitable choice of experimental conditions minimizing the influence of many other competing phenomena that usually complicate probing of this underlying physics is crucial for our study. A re-entrant behavior in the order-disorder phase diagram as a function of particle density and drying time is established and the results are explained with the help of simulations and phenomenological theory.