Implications of interface conventions for morphometric thermodynamics

TL;DR

This study investigates how interface conventions affect the accuracy of morphometric thermodynamics in modeling interfacial tensions for model fluids near curved walls, revealing its limitations and dependence on interface placement.

Contribution

It provides a detailed analysis of the limitations of morphometric thermodynamics for small densities and emphasizes the importance of interface location choices.

Findings

Morphometric thermodynamics is not exact for the studied systems.

The approximation quality depends on the interface location.

The study compares theoretical predictions with density functional theory results.

Abstract

Several model fluids in contact with planar, spherical, and cylindrical walls are investigated for small number densities within density functional theory. The dependence of the solid-fluid interfacial tension on the curvature of spherical and cylindrical walls is examined and compared with the corresponding expression derived within the framework of morphometric thermodynamics. Particular attention is paid to the implications of the choice of the interface location, which underlies the definition of the interfacial tension. We find that morphometric thermodynamics is never exact for the considered systems and that its quality as an approximation depends sensitively on the choice of the interface location.