In situ synthesis of the Ag/poly(4-vinylpyridine)-block-polystyrene composited nanoparticles by dispersion RAFT polymerization
Metal/block-copolymer composited nanoparticles are interesting and they are usually prepared by incorporating metal nanoparticles or metal ions into pre-prepared block copolymer nanoparticles. Herein, a new method of one-pot synthesis of the colloid-like metal/block-copolymer nanocomposites of poly(4-vinylpyridine)-block-polystyrene (P4VP-b-PS) and Ag nanoparticles by dispersion RAFT polymerization is proposed. This method employs the chelate polymer of poly(4-vinylpyridine) trithiocarbonate (P4VP-TTC) as both macro-RAFT agent for dispersion RAFT polymerization and stabilizer for Ag nanoparticles, and it affords the convenient synthesis of the Ag/P4VP-b-PS composited nanoparticles. In these Ag/P4VP-b-PS composited nanoparticles, Ag nanoparticles are uniformly embedded in the P4VP-b-PS nanoparticles. It is found that the size of the Ag/P4VP-b-PS composited nanoparticles increases either with the degree of polymerization of the polystyrene block or with the Ag fraction in the nanocomposites. This dispersion RAFT polymerization in the presence of macro-RAFT agent stabilized metal nanoparticles is believed to be an efficient method to synthesize concentrated metal/block-copolymer nanocomposites.