Facile Synthesis of Methacrylic ABC Triblock Copolymer Vesicles by RAFT Aqueous Dispersion Polymerization

Abstract

Poly(glycerol monomethacrylate-block-2-hydroxypropyl methacrylate) [PGMA–PHPMA] diblock copolymer vesicles are prepared by RAFT aqueous dispersion polymerization at 70 °C and then used as precursors for chain extension experiments with a third comonomer. For self-blocking experiments conducted with water-soluble HPMA, good living character is obtained, as judged by the relatively low final polydispersity (Mw/Mn < 1.30). This suggests that the RAFT chain-end fidelity is high, at least over time scales of a few hours. Using water-immiscible monomers such as methyl methacrylate (MMA) or benzyl methacrylate (BzMA) also leads to efficient chain extension under “seeded” emulsion polymerization conditions. High conversions are obtained within a few hours at 70 °C, but polydispersities are somewhat higher for the resulting ABC triblock copolymer chains. TEM studies indicate that introduction of a second hydrophobic block within the vesicle membrane produces remarkable changes in morphology. A distinctive framboid...