Width distribution of contact lines on a disordered substrate

TL;DR

This study measures the width distribution of a liquid contact line on a disordered substrate, revealing that the Joanny-de Gennes model does not fully capture the depinning dynamics, aligning with recent roughness exponent findings.

Contribution

It extends the analysis of contact line roughness to open boundary conditions and compares experimental data with theoretical predictions, challenging existing models.

Findings

Measured width distribution matches extended theoretical calculations.

Joanny-de Gennes model is insufficient for depinning dynamics.

Results agree with recent roughness exponent measurements.

Abstract

We have studied the roughness of a contact line of a liquid meniscus on a disordered substrate by measuring its width distribution. The comparison between the measured width distribution and the width distribution calculated in previous works, extended here to the case of open boundary conditions, confirms that the Joanny-de Gennes model is not sufficient to describe the dynamics of contact lines at the depinning threshold. This conclusion is in agreement with recent measurements which determine the roughness exponent by extrapolation to large system sizes.