Spinodal Dewetting of Thin Polymer Films

Abstract

Dewetting of polystyrene films on a silicon substrate is investigated as a function of film thickness $h$. We observe the nucleation of holes in the early stage of dewetting for relatively thick films $(h>100\AA{})$, as observed previously, but the breakup of thinner films occurs through the growth of uniformly distributed surface undulations (``spinodal dewetting''). The average amplitude $\ensuremath{\delta}h$ of these undulations increases exponentially up to the film rupture point where $\ensuremath{\delta}h$ becomes comparable to $h$, as predicted by a capillary wave instability model.