Structural and optical properties of hybrid materials derived from gold nanoparticles in different polystyrene (PS)-b-poly(4-vinylpyridine) (P4VP) matrices

Abstract

We introduce the preparation as well as the structural and optical properties of hybrid materials consisting of diblock copolymer matrices with gold nanoparticles. Anionically synthesized diblock copolymers of the PS-b-P4VP sequence, where PS: polystyrene and P4VP: poly(4-vinylpyridine) with well-defined characteristics were utilized as the polymer matrices. The specific pyridine-containing copolymers were selected due to their susceptibility to post-polymerization chemical modification reactions. Basic tertiary amines can be easily modified due to the presence of the nitrogen atom (N) in the 4-position (-para) of the aromatic ring in the monomeric units of poly(4-vinylpyridine). In this manner, the addition of either atoms or whole compounds as ion pairs is enabled. We report that the role of noble metal atoms in polymer matrices is dual. Firstly, microphase separation in the presence of heteroatoms occurs even in cases of extremely low molecular characteristics due to the increased repulsion between the components and secondly the excitation of plasmon resonance at the polymer/nanoparticle interface is induced. We believe that our work sheds light on the driving forces of self-assembly on the studied modified copolymers. The results strongly suggest that the hybrid materials can adopt well-defined morphologies even in very low molecular weights, a fact that renders them promising candidates for photonic applications.