Dewetting of thin viscoelastic polymer films on slippery substrates

Laboratoire de Physique de la Matière Condensée, FRE 2844 du CNRS Collège de France - 11 Place Marcelin Berthelot, 75231 Paris Cedex 05, France

Received: 19 May 2005
Accepted: 6 October 2005

Abstract

Dewetting of thin polystyrene films deposited onto silicon wafers exhibits unusual dynamics and rim 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 (i.e. slippage). We show how these two ingredients lead to: a) a very asymmetric shape of the rim as the film dewets; b) a decrease of the dewetting velocity with time like for times shorter than the reptation time (for larger times, the dewetting velocity reaches a constant value). Recent experiments by Damman, Baudelet and Reiter (Phys. Rev. Lett., 91 (2003) 216101) present, however, a much faster decrease of the dewetting velocity. We then show how this striking result may be explained by the presence of residual stresses in the film.