Composite PS-b-P4VP/Ag and PS-b-P4VP/Au thin films fabricated via a multilevel self-assembly process

Abstract

Thin composite films with paralleled nanowire or planar sheet morphologies doped with Ag or Au species were fabricated at the air/liquid interface. The fabrication process involves a series of steps, including the mass transfer of polystyrene-b-poly(4-vinylpyridine) (PS-b-P4VP) across a liquid/liquid interface between a DMF/CHCl₃ solution and an aqueous solution containing either Ag⁺ or AuCl₄⁻, self-assembly of the PS-b-P4VP and the inorganic species in the mixed DMF and water solution, and adsorption and further self-organization of the formed aggregates at the air/liquid interface. Noble metal ions and nanoparticles that formed during the fabrication process can be incorporated into the polymer matrices directly. The film morphology can be controlled through tuning the existential state and critical packing parameter of the polymer molecules. It was also found that the film morphology of PS-b-P4VP is distinctly different from that of PS-b-P2VP, indicating the great influence of the molecular structure on the self-assembly behavior of block copolymers. In addition, these composite thin films exhibit effective heterogeneous catalytic properties for hydrogenation of nitroaromatics in aqueous solutions.