Synthesis of poly(ethylene oxide)-based thermoresponsive block copolymers by RAFT radical polymerization and their uses for preparation of gold nanoparticles

• Published in: Colloids and surfaces. A, Physicochemical and engineering aspects Physicochemical and engineering aspects, 2008-03, Vol.317 (1), p.496-503
• Main Authors: Jeon, Hee Jung, Go, Da Hyeon, Choi, Song-yee, Kim, Kyung Min, Lee, Jae Yeol, Choo, Dong Joon, Yoo, Hyun-Oh, Kim, Jong Man, Kim, Jungahn
• Format: Article
• Language: English
• Subjects: Chemistry; Colloidal state and disperse state; Exact sciences and technology; General and physical chemistry; Physical and chemical studies. Granulometry. Electrokinetic phenomena; RAFT polymerization; Ring-opening polymerization; Surface physical chemistry; Thermoresponsive block copolymer; Water-soluble gold nanoparticles; Xanthate-type agent
• ISSN: 0927-7757; 1873-4359
• DOI: 10.1016/j.colsurfa.2007.11.033

The amphiphilic block copolymers were synthesized by reversible addition fragmentation chain transfer (RAFT) radical polymerization of N-isopropylacrylamide (NiPAM) using poly(ethylene oxide) (PEO)-based xanthate-type of RAFT agent and 2,2′-azobisisobutyronitrile (AIBN) in aqueous media at 85 °C for 12 h. The PEO-based RAFT agent could be easily synthesized by the reaction of terminally brominated PEO with o-ethylxantic acid potassium salt. The yield was over 95 mol% on the basis of incipient amount of polymeric alkoxide obtained from a ring opening polymerization of ethylene oxide. The different molecular weights of the poly( N-isopropylacrylamide) (PNiPAM) fragments of poly(ethylene oxide- b- N-isopropylacrylamide) played an important role to exhibit different thermoresponsive behaviors. The resulting block copolymers were successfully used as polymeric stabilizers to prepare water-soluble nano-sized gold particles. All the materials were characterized by the combination of 1H NMR, SEC, TEM, and XRD analyses.