Wandering of a contact line at thermal equilibrium

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.