Estimating Fluid-solid Interfacial Free Energies for Wettabilities: A Review of Molecular Simulation Methods

TL;DR

This review comprehensively evaluates molecular simulation methods for estimating fluid-solid interfacial free energies, highlighting their principles, applications, and potential to improve understanding of wetting behaviors in diverse systems.

Contribution

It provides a detailed summary and critical analysis of various molecular simulation techniques for fluid-solid IFE, emphasizing their development, implementation, and applications.

Findings

Multiple simulation methods can compute fluid-solid IFE and related properties.

Simulation approaches based on Navascues and Berry's theory are equivalent.

Adoption of these methods can enhance understanding of wetting phenomena.

Abstract

Fluid-solid interfacial free energy (IFE) is a fundamental parameter influencing wetting behaviors, which play a crucial role across a broad range of industrial applications. Obtaining reliable data for fluid-solid IFE remains challenging with experimental and semi-empirical methods, and the applicability of first-principle theoretical methods is constrained by a lack of accessible computational tools. In recent years, a variety of molecular simulation methods have been developed for determining the fluid-solid IFE. This review provides a comprehensive summary and critical evaluation of these techniques. The developments, fundamental principles, and implementations of various simulation methods are presented from mechanical routes, such as the contact angle approach, the technique using Bakker's equation, and the Wilhelmy simulation method, as well as thermodynamic routes, including the cleaving wall method, the Frenkel-Ladd technique, and the test-volume/area methods. These approaches can be applied to compute various fluid-solid interfacial properties, including IFE, relative IFE, surface stress, and superficial tension, although these properties are often used without differentiation in the literature. Additionally, selected applications of these methods are reviewed to provide insight into the behavior of fluid-solid interfacial energies in diverse systems. We also illustrate two interpretations of the fluid-solid IFE based on the theory of Navascues and Berry and Bakker's equation. It is shown that the simulation methods developed from these two interpretations are identical. This review advocates for the broader adoption of molecular simulation methods in estimating fluid-solid IFE, which is essential for advancing our understanding of wetting behaviors in various chemical systems.