PEO-b-PNIPAM copolymers via SARA ATRP and eATRP in aqueous media

Abstract

Supplemental activator and reducing agent atom transfer radical polymerization (SARA ATRP) and electrochemically mediated atom transfer radical polymerization (eATRP) of N-isopropylacrylamide were investigated in aqueous media. The synthesis of poly(ethylene oxide)-block-poly(N-isopropylacrylamide) copolymers via SARA ATRP was carried out, utilizing 500 ppm of CuII species, rather than previously reported ca. 2,500–50,000 ppm of CuI/L used to pre-disproportionate in situ to form Cu0 and CuII/L. The copolymers were also prepared via eATRP under potentiostatic conditions. Various polymerization parameters were examined including the effect of the targeted degree of polymerization (DP) and, in the case of SARA ATRP, the influence of copper surface area on the polymerization. Under optimized reaction conditions, the DP of resulting copolymers increased linearly with monomer conversion. Successful formation of the block copolymers confirmed the living nature of the polymers prepared by SARA ATRP and eATRP of N-isopropylacrylamide in aqueous media.