Amphiphilic Star-Block Copolymers By Iodide-Mediated Radical Polymerization

Amphiphilic star-block copolymers composed of polystyrene and poly( acrylic acid) were synthesized by iodide-mediated radical polymerization. Firstly, free radical polymerization of styrene was carried out with AIBN as initiator and 1,1,1-trimethyolpropane tri(2-iodoisobutyrate) as chain transfer agent, giving iodine atom ended star-shaped polystyrene with three arm chains, R( polystyrene)(3). Secondly, tert-butyl acrylate was polymerization using polystyrene obtained as macro-chain transfer agent, and star-block copolymer, R( polystyrene-b-poly(tert-butyl acrylate))(3) with controlled molecular weight was obtained. Finally, amphiphilic star-block copolymer, R(polystyrene-b-poly( acrylic acid))(3) was obtained by hydrolysis of R(polystyrene-b-poly(tert-butyl acrylate))(3) under acidic condition.