Multiscale dewetting of triblock copolymer thin film induced by solvent vapor

Multiscale dewetting of poly(styrene-b-ethylene/butylenes-b-styrene) (SEBS) triblock copolymer thin films induced by volatile solvent vapor treatment were observed in this study. Film rupture occurred at first and produced macroscopic holes. Near-regular droplets (which represented a compromise between complete disorder and perfect order) could be formed at the last stage. The mechanism of solvent-driven dewetting was discussed by comparing with that of thermal-induced dewetting. Similar to thermal-induced dewetting, the block copolymer thin films initially break up through the nucleation of holes that perforated the films. The rapid growing holes became unstable and formed nonequilibrium fingering patterns. The films exhibit autophobic or autodewetting phenomena. The velocity of the holes growth was nearly a constant (3.3 mu m/min). The stages of the dewetting were quite similar to that found for homopolymer and block copolymer thin films dewetting on solid or liquid substrates under thermal treatment. (c) 2005 Wiley Periodicals, Inc.