  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, the most
striking feature of all, that is a decrease of the rim width with time, have
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. In addition, we show how the introduction
of a non-linear friction can also simply explain the rapid decrease of the
dewetting velocity with time observed experimentally.
