Dewetting at the liquid-liquid interface

The dewetting behavior of a liquid film from a liquid substrate has been studied as a function of the substrate viscosity, using two highly viscous polymers as a model system. The dewetting velocity exhibits a minimum as a function of substrate viscosity. This behavior results from the competition of (1) the mass transport in the substrate, and (2) the retarded deformation of the liquid-liquid interface. Atomic force microscopy is used to image both the liquid-air interfaces and the buried liquid-liquid interface. The shape of the latter changes significantly with increasing substrate viscosity.