Patterned silica films using microphase separation of a block copolymer

Block copolymers exhibit various nanoscale ordered morphologies induced by microphase separation. Here, we present a method for providing two types of patterned silica films on Si wafer substrates simply by shifting the phase equilibrium of a block copolymer, polystyrene–block–poly(4–vinylpyridine) (PS–P4VP). In this method, siloxane is adsorbed onto poly(4–vinylpyridine) blocks of PS–P4VP whose structure varies with solvent polarity and is calcined to remove the block copolymer. Siloxane is in a dispersed phase with toluene as a solvent resulting in silica nanoparticle arrays, while siloxane is in a continuous phase with N, N-dimethylformamide (DMF) resulting in silica films with ordered mesopores. Since the pore size of silica films prepared in DMF is approximately 20 nm, the film has the ability to serve as a support for enzymes such as laccase.