An efficient way to tune grafting density of well-defined copolymers via an unusual Br-containing acrylate monomer

Abstract

A series of well-defined amphiphilic graft copolymers, containing hydrophilic poly(acrylic acid) backbone and hydrophobic poly(butyl acrylate) side chains, were synthesized by sequential reversible addition fragmentation chain transfer (RAFT) polymerization and atom transfer radical polymerization (ATRP) without any postpolymerization functionality modification followed by selective acidic hydrolysis of poly(tert-butyl acrylate) backbone. tert-Butyl 2-((2-bromopropanoyloxy)methyl)-acrylate was first homopolymerized or copolymerized with tert-butyl acrylate by RAFT in a controlled way to give ATRP-initiation-group-containing homopolymers and copolymers with narrow molecular weight distributions (Mw/Mn < 1.20) and their reactivity ratios were determined by Fineman-Ross and Kelen-Tudos methods, respectively. The density of ATRP initiation group can be regulated by the feed ratio of the comonomers. Next, ATRP of butyl acrylate was directly initiated by these macroinitiators to synthesize well-defined poly(tert-butyl acrylate)-g-poly(butyl acrylate) graft copolymers with controlled grafting densities via the grafting-from strategy. PtBA-based backbone was selectively hydrolyzed in acidic environment without affecting PBA side chains to provide poly(acrylic acid)-g-poly(butyl acrylate) amphiphilic graft copolymers. Fluorescence probe technique was used to determine the critical micelle concentrations in aqueous media and micellar morphologies are found to be spheres visualized by TEM. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2622–2630, 2010