Effect of criticality on wetting layers: A Monte-Carlo simulation study

TL;DR

This study uses Monte-Carlo simulations to investigate how critical fluctuations influence the thickness of wetting layers near the critical end point in binary fluid mixtures, revealing effects that could be observed experimentally.

Contribution

It demonstrates the impact of critical Casimir forces on wetting layer thickness near the critical end point through simulation, highlighting a novel interaction mechanism.

Findings

Critical fluctuations affect wetting layer thickness.

Monte-Carlo simulations reveal long-range Casimir forces.

Results suggest experimental detectability of these effects.

Abstract

A solid substrate, when exposed to a vapour, can interact with it in such a way that sufficiently close to liquid-vapour coexistence a macroscopically thick liquid wetting layer is formed on the substrate surface. If such a wetting transition occurs for a binary fluid mixture in the vicinity of the critical end point of demixing transitions, critical fluctuations lead to additional long-ranged interactions (Casimir forces) within the wetting layer, changing its equilibrium thickness. We demonstrate this effect by Monte-Carlo simulations of wetting layers of a symmetrical Lennard-Jones binary fluid mixture near its critical end point. The results suggest that the effect should also be detectable in corresponding wetting experiments.