  We compare the dispersion relations for spinodally dewetting thin liquid
films for increasing magnitude of interfacial slip length in the lubrication
limit. While the shape of the dispersion relation, in particular the position
of the maximum, are equal for no-slip up to moderate slip lengths, the position
of the maximum shifts to much larger wavelengths for large slip lengths. Here,
we discuss the implications of this fact for recently developed methods to
assess the disjoining pressure in spinodally unstable thin films by measuring
the shape of the roughness power spectrum. For PS films on OTS covered Si
wafers (with slip length b approx. 1 mum) we predict a 20% shift of the
position of the maximum of the power spectrum which should be detectable in
experiments.
