Cationic Surface-Active Monomers as Reactive Surfactants for AGET Emulsion ATRP of n-Butyl Methacrylate

A surface-active monomer 11′-(methacryloyloxy)-undecyl(trimethyl)ammonium bromide (MUTAB) was synthesized and used as a stabilizer and comonomer for activator generated by electron transfer atom transfer radical polymerization (AGET ATRP) of n -butyl methacrylate (BMA) in emulsion. This reactive “surfactant” was applied in a continuous two-step microemulsion to emulsion technique. Stable polymer latexes with size ranging from 40 to 200 nm were obtained by adjusting the amount of reactive surfactant introduced to the system. The surfactant concentration could be decreased to as low as 1.3 wt % in the final emulsion (5.9 wt % vs monomer), while still maintaining good colloidal stability. The cationic reactive surfactants were covalently anchored on the surfaces of the formed particles, as indicated by a positive zeta potential. In addition, a well-controlled polymerization process was achieved by ATRP, as evidenced by the smooth growth in molecular weight of the polymer chains as the polymerization progressed and by the formation of polymers with preserved chain-end functionalities.