Affiliation: | (1) Laboratoire de Chimie des Polymères, UMR 7610 associée au CNRS, Université Pierre et Marie Curie, tour 44, 1er étage, case 185, 4 place Jussieu, 75252 Paris Cedex 05, France;(2) Physicochimie des Polymères et des Milieux Dispersés, UMR7615, ESPCI-CNRS-UPMC, 10 rue Vauquelin, 75231 Paris cedex 05, France |
Abstract: | Well-defined, positively charged, amphiphilic copolymers containing long alkyl side chains were used as stabilizers in the miniemulsion polymerization of styrene. The copolymers were prepared by controlled free-radical copolymerization of styrene and vinyl benzyl chloride using either the reversible addition-fragmentation chain transfer method or TEMPO-mediated polymerization. The benzyl chloride moities were modified by two different long alkyl chain tertiary amines (N,N-dimethyldodecyl amine and N,N-dimethylhexadecyl amine) to yield the amphiphilic copolymers with vinylbenzyl dimethyl alkyl ammonium chloride units. Owing to their high structural quality, only a small amount of these copolymers was required to stabilize the latex particles (0.5–2 wt% vs styrene). Moreover, in the absence of any hydrophobic agent, the amphiphilic comblike copolymer preserved the colloidal stability of both the initial liquid miniemulsion and the final latex. Ill-defined, analogous copolymers were synthesized by conventional free-radical polymerization and in comparison, exhibited poor stabilization properties. |