Spinodal dewetting of thin liquid films at soft interfaces

We study theoretically the behavior of nanoscopic liquid films L (thickness e) intercalated between a solid S and a rubber R (elastic modulus mu). Thickness modulations involve a healing length zetaR, which results from a competition between elastic and disjoining pressure. With van der Waals interactions, zetaR = e(4)/(a(2)h(0)), where a is a molecular size and ho the rubber capillary length (h(0) = gamma LR/mu, gamma LR = L/R interfacial tension). If the Hamaker constant of the intercalated liquid is negative, the film dewets by amplification of peristaltic fluctuations ("spinodal dewetting"). The typical size of the S/R contacts is predicted to scale like zetaR for films of thicknesses e > rooth(0)a. The rise time tau of the fastest mode, predicted to scale like tau approximate to e(9), should be very sensitive to the film thickness.