Relaxation of a moving contact line and the Landau-Levich effect

¹ Laboratoire de Physique de la Matière Condensée, Collège de France URA No. 792 du CNRS - 11 place Marcelin-Berthelot, 75231 Paris Cedex 05, France
² Institute for Theoretical Physics, University of California Santa Barbara, CA 93106-4030, USA
³ Institute for Studies in Theoretical Physics and Mathematics P.O. Box 19395-5531, Tehran, Iran

Received: 14 December 2000
Accepted: 7 May 2001

Abstract

The dynamics of the deformations of a moving contact line is formulated. It is shown that an advancing contact line relaxes more quickly as compared to the equilibrium case, while for a receding contact line there is a corresponding slowing down. For a receding contact line on a heterogeneous solid surface, it is found that a roughening transition takes place which formally corresponds to the onset of leaving a Landau-Levich film. We propose a phase diagram for the system in which the phase boundaries corresponding to the roughening transition and the depinning transition meet at a junction point, and suggest that for sufficiently strong disorder a receding contact line will leave a Landau-Levich film immediately after depinning.