SynopsisMonodisperse stable latices with reactive methyl chloride surface functionalities were prepared in the presence of mixed surfactants using vinylbenzyl chloride in various ways: as a homopolymer, crosslinked with divinylbenzene, copolymerized with styrene, and overpolymerized onto uniform polystyrene latices. In homopolymerization of vinylbenzyl chloride, the effect of monomer content and concentration and type of surfactant are reported. Nucleophilic displacement of the surface chloride by sulfite ions was accomplished by reaction with aqueous sodium sulfite, without change in latex particle size. Also discussed are ways to control the amount of water-soluble polyelectrolyte produced as a result of the sulfonation reaction.