Eur. Phys. J. B 37, 127-136 (2004)
https://doi.org/10.1140/epjb/e2004-00037-9

Dissipation in the dynamics of a moving contact line: effect of the substrate disorder

Laboratoire de Physique Statistique de l'École Nomale Supérieure, associé au CNRS et aux Universités Paris 6 et Paris 7, 24 rue Lhomond, 75231 Paris Cedex 05, France

Corresponding author: ^a rolley@physique.ens.fr

Received: 13 June 2003
Revised: 6 October 2003
Published online: 19 February 2004

Abstract

We have studied the dynamics of the contact line of a viscous liquid on a solid substrate with macroscopic random defects. We have first characterized the friction force f₀ at microscopic scale for a substrate without defects; f₀ is found to be a strongly nonlinear function of the velocity U of the contact line. In presence of macroscopic defects, we find that the applied force F(U) is simply shifted with respect to  by a constant: we do not observe any critical behavior at the depinning transition. The only observable effect of the substrate disorder is to increase the hysteresis. We have also performed realistic numerical simulation of the motion of the contact line. Using the same values of the parameters as in the experiment, we find that the experimental data is qualitatively well reproduced. In light of experimental and numerical results, we discuss the possibility of measuring a true critical behavior.