Non-additivity of van der Waals forces on liquid surfaces

TL;DR

This paper models nanoscale wetting and dewetting by computing non-additive van der Waals forces, revealing significant differences from traditional additive approximations in predicting liquid surface shapes and wetting transitions.

Contribution

It introduces a method to account for non-additivity of vdW forces in modeling liquid surfaces, improving accuracy over traditional additive approaches.

Findings

Non-additivity significantly affects liquid surface profiles.

Traditional additive models can mispredict wetting transitions.

The approach improves understanding of nanoscale wetting phenomena.

Abstract

We present an approach for modeling nanoscale wetting and dewetting of liquid surfaces that exploits recently developed, sophisticated techniques for computing van der Waals (vdW) or (more generally) Casimir forces in arbitrary geometries. We solve the variational formulation of the Young--Laplace equation to predict the equilibrium shapes of fluid--vacuum interfaces near solid gratings and show that the non-additivity of vdW interactions can have a significant impact on the shape and wetting properties of the liquid surface, leading to very different surface profiles and wetting transitions compared to predictions based on commonly employed additive approximations, such as Hamaker or Derjaguin approximations.