The linear-type bifunctional vinyl urethane macromonomer (L-VUM: Mw; 40,453) was synthesized and applied to emulsion polymerization of styrene in DDI water. The structure of L-VUM was confirmed using H-1 NMR and FT-IR. The macromonomer served as a good nonionic surfactant resulted in stable polystyrene nanospheres. Polystyrene particles were prepared with various concentrations of macromonomoer (1-30 wt% refer to monomer), initiator (0.5-2 wt%) and different temperatures (60-80 degrees C). Monodisperse PS nanospheres with 30 wt%, L-VUM have a number-average diameter (D-n) of 200 nm with good uniformity (1.011) and molecular weight (M-w) 231,180 g/mol. The particle morphology, molecular weight and distribution, uniformity and the stability of the nanospheres upon the reaction temperature and concentration of LNUM will be thoroughly discussed. (C) 2007 Published by Elsevier B.V.