Nanopattern formation using a chemically modified PS-P4VP diblock copolymer

A slight betainization of the amphiphilic block copolymer polystyrene-block-poly(4-vinylpyridine) (PS-P4VP) was carried out by the introduction of 1,3-propane sultone into the P4VP block. The micellar film cast from the new copolymer solution exhibited hexagonal packing which is similar to the copolymer film prior to modification. An interesting core-corona inversion was induced in situ with water, a selective solvent for P4VP, due to the increased water sensitivity. The effect of annealing on a PS-P4VP-sultone micellar film was investigated both with and without solvent environment. The latter gives rise to a reduction in the nanodot dimension while the former leads to the formation of a nanostrand morphology. This procedure thus adds a simple yet effective tool for controlling pattern formation.