Effects of an embedding bulk fluid on phase separation dynamics in a thin liquid film

TL;DR

This study uses dissipative particle dynamics simulations to show how embedding a bulk fluid in a thin liquid film changes phase separation dynamics from 2D to 3D behavior, affecting domain growth and diffusion properties.

Contribution

It demonstrates the impact of a bulk fluid on phase separation dynamics and diffusion behavior in thin films, revealing a transition from 2D to 3D-like domain growth.

Findings

Domain growth exponent shifts from 2D to 3D behavior with bulk fluid addition.

Diffusion coefficient dependence changes from logarithmic to algebraic.

Phase separation proceeds via Brownian coagulation process.

Abstract

Using dissipative particle dynamics simulations, we study the effects of an embedding bulk fluid on the phase separation dynamics in a thin planar liquid film. The domain growth exponent is altered from 2D to 3D behavior upon the addition of a bulk fluid, even though the phase separation occurs in 2D geometry. Correlated diffusion measurements in the film show that the presence of bulk fluid changes the nature of the longitudinal coupling diffusion coefficient from logarithmic to algebraic dependence of 1/s, where s is the distance between the two particles. This result, along with the scaling exponents, suggests that the phase separation takes place through the Brownian coagulation process.