Disjoining Pressure and the Film-Height-Dependent Surface Tension of Thin Liquid Films: New Insight from Capillary Wave Fluctuations

TL;DR

This paper reviews how thermal capillary wave fluctuations can be used to probe disjoining pressure and surface tension in thin liquid films, revealing a film-height dependence not explained by classical models, with implications for interfacial thermodynamics.

Contribution

It introduces a new understanding of film-height-dependent surface tension derived from statistical thermodynamics, challenging classical interfacial models.

Findings

Simulation results show surface tension varies with film height.

The observed dependence can be explained from thermodynamic principles.

Implications for modeling thin film interfaces are discussed.

Abstract

In this paper we review simulation and experimental studies of thermal capillary wave fluctuations as an ideal means for probing the underlying disjoining pressure and surface tensions, and more generally, fine details of the Interfacial Hamiltonian Model. We discuss recent simulation results that reveal a film-height-dependent surface tension not accounted for in the classical Interfacial Hamiltonian Model. We show how this observation may be explained bottom-up from sound principles of statistical thermodynamics and discuss some of its implications.