Formation and morphology of methacrylic polymers and block copolymers tethered on polymer microspheres

We report the use of atom transfer radical polymerization (ATRP) to graft off polymeric microspheres. Residual vinyl groups on nonswellable poly(divinylbenzene-80) microspheres were converted into ATRP initiators by hydroboration/oxidation followed by esterification. Subsequent grafting by ATRP of poly(hydroxylethyl methacrylate) (poly(HEMA)) and poly((dimethylamino)ethyl methacrylate) (poly(DMAEMA)) led to hydrophilically modified microspheres. The surface properties of these microspheres, FT-IR spectra, and potentiometric titration confirm the successful modification. In addition, swellable, lightly cross-linked poly(DVB-co-HEMA) microspheres were modified in a similar manner by grafting, i.e., methyl methacrylate (MMA) and glycidyl methacrylate (GMA), to form graft block copolymers including poly(MMA-b-DMAEMA), poly(MMA-b-trimethylammonium ethylmethacrylate (TMAEMA)), and poly(MMA-b-GMA). Microphase separation of the grafted amphiphilic block copolymers was studied by scanning electron microscopy. The microspheres modified with poly(MMA-b-DMAEMA) and poly(MMA-b-TMAEMA) show polyelectrolyte properties.