Controlling the ordered transition of PS-b-P4VP block copolymer ultrathin films by solvent annealing

A change in morphology of ultrathin films of polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) diblock copolymer was induced by annealing under chloroform and toluene vapor and was investigated by atomic force microscopy (AFM). The microphase separation morphology with spherical structures were formed when PS-bP-4VP was dissolved in toluene, which is a selective solvent for polystyrene (PS) segments. After chloroform annealing, a series of surface morphologies of PS-b-P4VP were observed, including spherical and network structures such as gyroid structures. During the continuous annealing treatment for the films with network structures by toluene, a reversible structure conversion from network to sea-island was observed. In addition, we have demonstrated that Au-NPs can be easily adhered to the PS-b-P4VP films with network structure on surface.