This is the first study of the effect of structure of the surfmer on the stability, morphology, and kinetics of the emulsion polymerization of butyl acrylate (BuA) and methyl methacrylate (MMA). Poly(ethylene glycol) behenyl ether methacrylate (PEGBEMA) was used as surfmer in the emulsion polymerization [GRAPHICS] of BuA and MMA and compared with the same type surfmer with different backbone structure (with four bulky phenyl groups in the backbone of the surfmer) poly(ethylene glycol) 2,4,6-tris (1-phenylethyl) phenyl ether methacrylate. [GRAPHICS] It was found that the straight chain surfmer produces less stability, lower order reaction less particles size (D-max) greater number of polymer particles N-t, worse morphology D-w/D-n, than the bulky surfmer. The order of polymerization reaction of BuA with respect to PEGBEMA was 0.8 compared with 2.6 in case of using PEGTPMA. The surface charge density was dramatically changed when using PEGBEMA from 39.8 to 204 mu C in case of PEGTPMA at the same conditions of surfmer concentration, temperature, and other parameters. The D-v was found to be 897 nm for particles prepared in the presence of PEGTPMA surfmer while it was 159 nm for particles prepared in the presence of PEGBEMA at the same surfmer concentrations and other experimental conditions. (c) 2008 Wiley Periodicals, Inc.