INTERFACIAL INSTABILITY DRIVEN BY DISPERSIVE FORCES : THE EARLY STAGES OF SPINODAL DEWETTING OF A THIN POLYMER FILM ON A POLYMER SUBSTRATE

The interface between ultrathin deuterated poly(methyl methacrylate) films on polystyrene substrates is subject to a dispersive force driven instability consisting of thermally excited capillary waves. We have studied this example of liquid/liquid spinodal dewetting, using specular and off-specular neutron reflection measurements to characterize the length scale and growth rate of the instability of the buried, polymer interfaces.