Anistropic hole formation in thin polymer films confined by walls

We report dewetting behavior of thermally annealed thin polymer strips of p oly (styrene-b-butadiene-b-styrene) and polystyrene films that are laterall y confined by polydimethylsiloxane walls on silicon substrate. Regularly sp aced holes are initially nucleated on the polymer surface and then grow wit h the aid of the confining walls, resulting in the formation of distinctly observable, regularly spaced blocks of the strip. It is observed that the d ependence of hole density on the film thickness severely deviates from the conventional capillary wave model. This anomaly may be related to the visco leastic properties of the polymer film. (C) 2001 American Institute of Phys ics.