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 1H NMR spectroscopy confirmed that the integrity of the polymer backbone was maintained and that the vinyl sulfone was successfully incorporated at the chain end.