A kind of polymerizable surfactant, methacryloyloxyethylhexadecyldimethylammonium bromide (DNMB) was used to synthesis soap-free cationic emulsion with styrene (St), methyl methacrylate (NMA), and methacryloyloxyethyltrimethylammonium chloride (MATMAC) by emulsion polymerization using 2,2'-azobis(isobutylamidine hydrochloride) (AIBA) as a cationic initiator. The effects of polymerizable surfactant concentration, initiator concentration, and reaction temperature on the conversion of monomer were investigated. The results indicated that the rate of polymerization could be expressed as R-p = k(p)[AIBA](0.42)[DMHB](0.45) and the apparent activation energy (E-a) was 83.42 kJ/mol. The particle size, potential, and apparent charge density of cationic latices were also measured. The average diameter of copolymer particles decreased with increasing DMHB, MATMAC, and AIBA content; the charge properties of the particles were decided by the DMHB, MATMAC, and AIBA content. The polymerization mechanism is discussed. (c) 2005 Wiley Periodicals, Inc.