Thin block copolymers films: film formation and corrugation under an AFM tip

The tip of an atomic force microscope was used to induce nanoscale ordering in thin films of polystyrene-poly(4-vinyl pyridine) block copolymers under low force. The AEM tip produces rims on a mesoscopic scale oriented perpen dicularly to the scanning direction. A wide range of molecular weights of b oth blocks was investigated and it was found that after two scans and at co nstant polymer length there is a linear relationship between the fraction o f polystyrene in the polymer and the average separation between two success ive rims. Scanning the area in between two rims showed that there is no pol ymer left on the surface. This is an indication that the mobility of the po ly( 4-vinylpyridine) anchor blocks is high during sliding of the tip. Diffe rent methods for the preparation of the thin polymer films went investigate d. A scaling model for diblock copolymer adsorption was used to interpret t he results. (C) 2000 Elsevier Science S.A. All rights reserved.