Poly(methyl acrylate) and amphiphilic copolymer of butyl acrylate and acrylic acid were prepared in the presence of 1,1-diphenylethene (DPE) by gamma-irradiation-induced polymerization. The influences of polymerization time, amounts of DPE in system on conversion, molecular weight (MW), and its distribution (M-w/M-n) were studied. The results indicate that the polymerization in the presence of DPE and initiated by gamma-irradiation shows the character of controlled radical reaction. The prepared copolymer was used as the polymeric emulsifier in the emulsion polymerizations of butyl acrylate (BA) and styrene (St), respectively, to assess the possibility of making monodisperse latices of relatively high solids content (similar to 35-45%) in an one-step batch process. (C) 2007 Wiley Periodicals, Inc.