Recently, Nagasaki et al. [Macromol. Rapid Commun. 1997, 18, 827-835] reported that certain heteroatom methacrylate monomers such as 2-(diethylamino)ethyl methacrylate (DEAEMA) can be polymerized at room temperature using oxyanionic initiators such as potassium ethoxide. Furthermore, functional initiators such as potassium 4-vinylbenzyl alcoholate produced styrene-functionalized macromonomers. We have utilized this chemistry to synthesize a range of novel, well-defined water-soluble macromonomers based on 2-(dimethylamino)ethyl methacrylate (DMAEMA) and other tertiary amine methacrylates. These macromonomers were typically contaminated with small amounts of residual initiator, but this could be easily removed by precipitation into n-hexane. NMR and GPC studies confirmed that each poly(DMAEMA) chain had a polymerizable styrene end group. Selected macromonomers were used to prepare submicrometer-sized and micrometer-sized polystyrene latexes via aqueous emulsion and nonaqueous dispersion polymerization, respectively. The terminal functional group participates in the styrene polymerization, leading to chemical grafting of the macromonomer onto the outside of the latex particles. The presence of the stabilizer in the latexes was confirmed by FTIR spectroscopy and nitrogen microanalyses. The adsorbed amount of macromonomer varied between 0.5 and 4.6 mg m(-2) The first examples of well-defined, sulfobetaine-based macromonomers were obtained by derivatizing selected DMAEMA macromonomers with 1,3-propane sultone. One of these macromonomers proved to be an effective steric stabilizer for the synthesis of polystyrene latexes at high electrolyte concentration (1.0 M NaCl).