The first amphiphilic graft copolymer bearing a hydrophilic poly(2-hydroxylethyl acrylate) backbone synthesized by successive RAFT and ATRP

Abstract

A series of well-defined amphiphilic graft copolymers consisting of a hydrophilic poly(2-hydroxyethyl acrylate) (PHEA) backbone and hydrophobic polystyrene side chains were synthesized by the combination of reversible addition–fragmentation chain transfer (RAFT) polymerization, atom transfer radical polymerization (ATRP), and the grafting-from strategy. A new acrylate monomer containing an ATRP initiating group, 2-hydroxyethyl 2-[(2-chloropropanoyloxy)methyl]acrylate, was first prepared via a four-step procedure using 2-hydroxyethyl acrylate as a starting material. This monomer was then RAFT homopolymerized to give a PHEA-based homopolymer bearing a Cl-containing ATRP initiating group in every repeating unit with a narrow molecular weight distribution (M_w/M_n = 1.08). This homopolymer directly initiated the ATRP of styrene to afford the desired well-defined poly(2-hydroxyethyl acrylate)-graft-polystyrene graft copolymers (M_w/M_n ≤ 1.30) containing a hydroxyl in every repeating unit of the backbone without polymeric functionality transformation. The self-assembly behavior of the amphiphilic graft copolymers obtained was investigated by dynamic light scattering and transmission electron microscopy.