Hierarchical composite microstructures fabricated at the air/liquid interface through multilevel self-assembly of block copolymers

Hierarchical composite microstructures of block copolymers, polystyrene-b-poly(2-vinylpyridine) (PS-b-P2VP)/Ag have been fabricated successfully at the air/liquid interface through a self-assembly and adsorption process. The films with various morphologies including foam, nanorod and nanowire array, hollow sphere, and nanosphere were obtained. These morphologies are closely related to the aggregates formed in the aqueous phase, such as microcapsules, cylindrical micelles, vesicles and spherical micelles, which can be controlled by tuning the critical packing parameters of the amphiphilic block copolymer molecules through changing the concentration of Ag+ ions in the aqueous solution. The length of the P2VP blocks in the PS-b-P2VPs exerts great influences on the self-assembly behavior of the polymers and the final microstructures, which provides a deep insight into the formation mechanism of the microstructures. Additionally, these hybrid films doped with silver nanoparticles provide potential application in surface enhanced Raman scattering (SERS) and catalysis. (C) 2016 Elsevier B.V. All rights reserved.