STATIC AND DYNAMIC WETTING PROPERTIES OF THIN RUBBER FILMS

We model the statics and dynamics of wetting of liquids on thin rubber films. We show that at equilibrium the capillary forces deform soft s ubstrates, leading to undulations of the rubber film surface originati ng at the triple Line. Such deformations propagate when a liquid sprea ds on the rubber film. This induces the dissipation that may control t he spreading dynamics. We derive a general expression for this dissipa tion as a function of the viscoelastic properties of the substrate. We calculate the spreading velocities for various mechanical relaxation models. Using available mechanical relaxation data, we find that our m odel may well account for the experimental observations of Carre and S hanahan, who demonstrated the importance of viscoelastic braking effec ts.