The role of nonlinear friction in the dewetting of thin polymer films

¹ Laboratoire de Physico-Chimie Théorique, UMR CNRS 7083, ESPCI 10 rue Vauquelin, F-75231 Paris Cedex 05, France
² Laboratoire de Physicochimie des Polymères, Université de Mons Hainaut 20 Place du Parc, B-7000 Mons, Belgium
³ MateriaNova Research Center - Mons, Belgium
⁴ Institut de Chimie des Surfaces et Interfaces, CNRS-UHA 15 rue Jean Starcky, B.P. 2488, F-68057 Mulhouse cedex, France
⁵ Laboratoire de Chimie Analytique, Matériaux, Surfaces et Interfaces Département de Chimie, Faculté des Sciences I, Université Libanaise Hadeth, Beyrouth, Lebanon

Received: 24 October 2005
Accepted: 24 January 2006

Abstract

The study of the dewetting of very thin polymer films has recently revealed many unexpected features (e.g. unusual rim morphologies and front velocities) which have been the focus of several theoretical models. Surprisingly, one of the most striking features, that is the decrease of the rim width with time, has not yet been explained. In the present letter, we show how the combined effects of a non-linear friction between the film and the substrate, and the presence of residual stresses within the film, result in the presence of a maximum in the time evolution of the rim width. Our model allows a quantitative evaluation of the residual stresses and a characterization of the friction between the polymer film and the substrate. In addition, we show how the introduction of a non-linear friction simply explains the experimentally observed rapid decrease of the dewetting velocity with time.