Dewetting of Thin Viscoelastic Polymer Films on Slippery Substrates

الأصل · EN

Dewetting of thin polystyrene films deposited onto silicone wafers at temperatures close to the glass transition exhibits unusual dynamics and front morphologies. Here, we present a new theoretical approach of these phenomena taking into account both the viscoelastic properties of the film and the non-zero velocity of the film at the interface with the substrate (due to slippage). We then show how these two ingredients lead to: (a) A very asymmetric shape of the rim as the film dewetts, (b) A decrease of the dewetting velocity with time like t-1/2 for times shorter than the reptation time (for larger times, the dewetting velocity reaches a constant value). Very recent experiments by Damman, Baudelet and Reiter [Phys. Rev. Lett. 91, 216101 (2003)] present, however, a much faster decrease of the dewetting velocity. We then show how this striking result can be explained by the presence of residual stresses in the film.