Dewetting at Soft Interfaces

We observe by optical interferometry the removal of a thin liquid film (thickness in the range of 100 nm) intercalated between a soft rubber and a hydrophobic glass plate. The film dewets by nucleation and growth of a single solid/rubber contact. The dry patch is surrounded by a very flat rim that collects the liquid. We find that (i) the shape of the rim squeezed by the rubber is quasistatic, and (ii) the radius $R\left(t\right)$ of the contact increases with time $t$ according to an unusual power law $R\left(t\right)\propto t^{3/4}$. These results can be interpreted in terms of a hydrodynamic model, assuming viscous dissipation in the moving rim while the rubber is purely elastic.