Wandering of a contact line at thermal equilibrium

TL;DR

This paper analytically investigates the fluctuations of a contact line at thermal equilibrium on a disordered substrate, incorporating gravity effects for accurate comparison with experiments on liquid helium wetting caesium.

Contribution

It introduces an analytic replica variational approach to study contact line fluctuations, extending beyond scaling arguments and including gravity effects for better experimental alignment.

Findings

Theoretical predictions match experimental data for helium wetting on caesium.

Gravity effects are essential for accurate modeling of contact line fluctuations.

Analytic computation provides new insights into the collective pinning regime.

Abstract

We reconsider the problem of the solid-liquid-vapour contact-line on a disordered substrate, in the collective pinning regime. We go beyond scaling arguments and perform an analytic computation, through the replica variational method, of the fluctuations of the line. We show how gravity effects must be included for a proper quantitative comparison with available experimental data of the wetting of liquid helium on a caesium substrate. The theoretical result is in good agreement with experimental findings for this case.