STUDIES ON FIBERLIKE MICELLES OF STAR BLOCK COPOLYMER/GOLD NANOPARTICLES HYBRID MATERIAL

The star-block copolymers poly(styrene)-block-poly(4-vinylpyridine) (PS-b-P4VP)(4) were. synthesized by two-step atom transfer radical polymerization (ATRP) using pentaerythritol tetrakis 2-bromoisobutyrate a, initiator. The structure and molecular weight of polymers was experimentally confirmed by (1)-HNMR spectroscopy,gel permeation chromatography (GPC) and IR, respectively. The star-block copolymers formed fiberlike micelles in toluene with the P4VP core and the PS petal-like shell. The micellar size and morphology were investigate(] by transmission electron microscope (TEM) and -,can electron microscope (SEM, respectively. The results showed the fiberlike micelles were tens microns in length but only fifty nanometers in width. In order to learn the fiberlike micelle formation mechanism, four star-block copolymer,,, with the same length of PS blocks but different lengths of P4VP were self-assembled, and their morphology showed a transition from sphere to fiberlike with increasing the lengths of P4VP. The stretching of the longer PVP was restricted in micellar core, which made the sphere micelles with small radius of curvature transformation into rod micelles with lager radius of curvature. As the template of fiberlike micelles, the one-dimensional nano-materials with ordered arrays of gold nanoparticles were obtained by reducing HAuCl4 center dot 3H(2)O complex with micelles.