Effect of substrate surface on dewetting behavior and chain orientation of semicrystalline block copolymer thin films.

Three symmetrical semicrystalline oxyethylene/oxybutylene block copolymers (E m B n ) were spin-coated on different substrates including silicon, hydrophobically modified silicon, and mica. The effects of surface property on the dewetting behavior of E m B n thin films and the chain orientation of the crystalline block were investigated with atomic force microscopy and grazing incidence X-ray diffraction . The E m B n thin films on silicon exhibit an autophobic dewetting behavior, while ordinary dewetting occurs for the thin films on modified silicon. It was observed that the stems of the E crystals in the first half-polymer layer contacting the mica surface were parallel to the surface, in contrast to the perpendicular chain orientation of the other polymer layers and of the first half-polymer layer on silicon. This is attributed to the strong interaction between the E block and mica, verified by infrared spectra.