Statistical copolymerization of a 1:1 molar ratio of 2-hydroxyethyl methacrylate (HEMA) with 4-hydroxybutyl methacrylate (HBMA) has been conducted in water via reversible addition-fragmentation chain transfer (RAFT) polymerization using a poly(glycerol monomethacrylate) (PGMA) stabilizer. Given the water-solubility of both the PGMA macro-CTA and the free radical azo initiator, it is perhaps counter-intuitive that the water-immiscible HBMA is initially consumed significantly faster than the water-miscible HEMA, as judged by 1H NMR studies of this copolymerization. However, both comonomers are almost fully consumed within 3 h at 70oC. A detailed phase diagram has been constructed for this RAFT statistical copolymerization formulation that enables reproducible syntheses of pure copolymer sphere, worm and vesicle morphologies. Remarkably, the thermo-responsive behavior of the PGMA-P(HBMA-stat-HEMA) copolymer worm gels can differ qualitatively from that exhibited by PGMA-PHPMA diblock copolymer worm gels (see A. Blanazs et al. Macromolecules, 2012  , 45, 5099), even though their core-forming blocks are essentially isomeric.

RAFT polymerization of hydroxy-functional methacrylic monomers under heterogeneous conditions: Effect of varying the core-forming block

248th National Meeting (2014)

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