Modelling the evaporation of thin films of colloidal suspensions using Dynamical Density Functional Theory

TL;DR

This paper develops a dynamical density functional theory model to simulate and analyze the formation of complex nano-structures during the evaporation of thin colloidal suspension films, highlighting the roles of evaporation, diffusion, and phase separation.

Contribution

It introduces a novel dynamical density functional theory model that captures the formation of diverse nano-structures during colloidal film evaporation, linking phase separation to self-organization.

Findings

The model reproduces experimentally observed structures.

Evaporation rate and particle diffusion significantly influence structure formation.

Phase separation conditions affect nano-structure morphology.

Abstract

Recent experiments have shown that various structures may be formed during the evaporative dewetting of thin films of colloidal suspensions. Nano-particle deposits of strongly branched `flower-like', labyrinthine and network structures are observed. They are caused by the different transport processes and the rich phase behaviour of the system. We develop a model for the system, based on a dynamical density functional theory, which reproduces these structures. The model is employed to determine the influences of the solvent evaporation and of the diffusion of the colloidal particles and of the liquid over the surface. Finally, we investigate the conditions needed for `liquid-particle' phase separation to occur and discuss its effect on the self-organised nano-structures.