Synthesis of Michael Acceptor Ionomers of Poly(4-Sulfonated Styrene-co-Poly(ethylene Glycol) Methyl Ether Acrylate)

Ionomers containing sodium 4-styrene sulfonate (4SS) and poly(ethylene glycol) methyl ether acrylate (PEGA) were synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization. The polymerization was mediated by 1-phenylethyl dithiobenzoate chain transfer agent in a dimethylformamide/water solvent system. Well-defined copolymers of pPEGA-co-4SS were produced with molecular weights ranging from 10 to 40 kDa and polydispersity indices of 1.06-1.18 by gel permeation chromatography against monodisperse poly(methyl methacrylate) standards. After polymerization, the dithioester was reduced and trapped in situ with divinyl sulfone to produce a well-defined, semitelechelic pPEGA-co-4SS Michael acceptor polymer. UV-visible, infrared, and H-1 NMR spectroscopy confirmed that the integrity of the polymer backbone was maintained and that the vinyl sulfone was successfully incorporated at the chain end.