Stability of thin polar films on non-wettable substrates

Abstract

The linear and non-linear stabilities of thin (<50 nm) apolar and polar films (water, polymers) on non-wettable substrates are correlated to the macroscopic parameters of wetting. The wavelength of instability and the time of film rupture decline as the substrate becomes less wettable by macroscopic drops. The instability of relatively thick (>12 nm) completely polar films (e.g. water films bounded by octane) evolves very slowly, and the substrate may appear to be wettable, notwithstanding a large equilibrium contact angle. In contrast to the apolar films, the non-linear interactions in polar films may remain significant even for the small-amplitude thermal perturbations.