BURSTING OF A LIQUID-FILM ON A LIQUID SUBSTRATE

We study metastable PolyDimethylSiloxane (PDMS) films deposited on a substrate of fluorinated PDMS: after nucleation, a hole grows at constant velocity V. V is inversely proportional to the substrate viscosity and is proportional to -S, where S(< 0) is the spreading parameter. The velocity is a decreasing function of the film thickness e; the detailed V(e) law can be interpreted by a balance between capillary forces and viscous forces acting on an almost flat rim.