Ordered gold nanoparticle arrays obtained with supramolecular block copolymers

Abstract

We demonstrate a simple approach to produce self-assembly of nanocomposites of gold nanoparticles with a supramolecular block copolymer formed by a fan-shaped small molecule L and polystyrene-b-poly(4-vinyl pyridine) (PS-b-P4VP) through hydrogen bonding. Hybrids PS-b-P4VP(L)_n, where n is the molar ratio of L to 4VP, were obtained by blending the polymer PS-b-P4VP, the small molecule L, and gold nanoparticles. With the use of the supramolecular approach, chemical modification of either the nanoparticle or the polymer is unnecessary. The organization of Au nanoparticles with controlled inter-particle distance and ordering was realized by changing the value of n. In addition, a hierarchical structure-within-structure morphology was observed for one of the hybrids, Au/PS-b-P4VP(L)_1.0, in which the Au/P4VP(L)_n domains form a hexagonal packing stabilized by nano-phase separation. The hybrids self-assemble into sphere, lamella, or cylinder structures, which were characterized by small-angle X-ray scattering and transmission electron microscopy. The contents of both L and Au NPs can affect the type and size of the self-assembled structure.