Wetting transitions at soft, sliding interfaces.
We observe (by optical interferometry) the contact of a rubber cap squeezing a nonwetting liquid against a plate moving at velocity U. At low velocities, the contact is dry. It becomes partially wet above a threshold velocity V(c1), with two symmetrical dry patches on the rear part. Above a second velocity V(c2), the contact is totally wet. This regime U>V(c2) corresponds to the hydroplaning of a car (decelerating on a wet road). We interpret the transitions at V(c1), V(c2) in terms of a competition between (a) liquid invasion induced by shear (b) spontaneous dewetting of the liquid (between nonwettable surfaces).
Martin
A
A
Institut Curie, Section de Physique et Chimie, Laboratoire de Physico-Chimie des Surfaces et Interface, 11 rue Pierre et Marie Curie, 75231 Paris Cedex 05, France.
Clain
J
J
Buguin
A
A
Brochard-Wyart
F
F