Curvature corrections to the nonlocal interfacial model for short-ranged forces

TL;DR

This paper rigorously derives curvature corrections to a nonlocal interfacial Hamiltonian model for short-ranged forces, improving understanding of interfacial phenomena near substrates and free interfaces.

Contribution

It provides a rigorous boundary integral derivation of curvature corrections for various interfacial scenarios, refining existing models and proposing an improved diagrammatic formulation.

Findings

Correct form of curvature corrections identified for contact with substrates and free interfaces

Reformulation of interfacial self-interaction as conjectured in prior literature

Enhanced diagrammatic approach for nonlocal binding potential

Abstract

In this paper we revisit the derivation of a nonlocal interfacial Hamiltonian model for systems with short-ranged intermolecular forces. Starting from a microscopic Landau-Ginzburg-Wilson Hamiltonian with a double parabola potential, we reformulate the derivation of the interfacial model using a rigorous boundary integral approach. This is done for three scenarios: a single fluid phase in contact with a nonplanar substrate (i.e., wall); a free interface separating coexisting fluid phases (say, liquid and gas); and finally a liquid-gas interface in contact with a nonplanar confining wall, as is applicable to wetting phenomena. For the first two cases our approaches identifies the correct form of the curvature corrections to the free energy and, for the case of a free interface, it allows us to recast these as an interfacial self-interaction as conjectured previously in the literature. When the interface is in contact with a substrate our approach similarly identifies curvature corrections to the nonlocal binding potential, describing the interaction of the interface and wall, for which we propose a generalized and improved diagrammatic formulation.