Liquid nanofilms. A mechanical model for the disjoining pressure

TL;DR

This paper introduces a mechanical model for liquid nanofilms that accounts for intermolecular forces, enabling analytical determination of disjoining pressure and aligning well with experimental data.

Contribution

It presents a novel square-gradient functional model incorporating surface liquid density functionals for thin nanofilms near solid walls.

Findings

Analytical expression for disjoining pressure in nanofilms.

Model predictions agree with experimental curves.

Provides insights into nanofilm stability and structure.

Abstract

Liquids in contact with solids are submitted to intermolecular forces making liquids heterogeneous and, in a mechanical model, the stress tensor is not any more spherical as in homogeneous bulks. The aim of this article is to show that a square-gradient functional taking into account the volume liquid free energy corrected with two surface liquid density functionals is a mean field approximation allowing to study structures of very thin liquid nanofilms near plane solid walls. The model determines analytically the concept of disjoining pressure for liquid films of thicknesses of a very few number of nanometers and yields a behavior in good agreement with the shapes of experimental curves carried out by Derjaguin and his successors.