Macromolecules 2008, 41, 8429-8435
8429
Aqueous RAFT Synthesis of pH-Responsive Triblock Copolymer mPEO-PAPMA-PDPAEMA and Formation of Shell Cross-Linked Micelles† Xuewei Xu,‡ Adam E. Smith,‡ Stacey E. Kirkland,‡ and Charles L. McCormick*,‡,§ Department of Polymer Science and Department of Chemistry and Biochemistry, The UniVersity of Southern Mississippi, Hattiesburg, Mississippi 39406 ReceiVed July 29, 2008; ReVised Manuscript ReceiVed September 8, 2008
ABSTRACT: Herein we report the synthesis and characterization of polymeric cross-linking agents and novel shell cross-linked (SCL) micelles utilizing reversible addition-fragmentation chain transfer (RAFT) polymerization. A series of pH-responsive ABC triblock copolymers consisting of R-methoxypoly(ethylene oxide)-b-poly[N-(3aminopropyl)methacrylamide]-b-poly[2-(diisopropylamino)ethyl methacrylate] (mPEO-PAPMA-PDPAEMA) have been synthesized via RAFT polymerization in aqueous media at 70 °C employing a PEO-based macrochain transfer agent (macro-CTA). These triblock copolymers molecularly dissolve in aqueous solution at low pH (