The monodispersed latex particles were prepared by soap-free emulsion copolymerization of styrene(St) with hydroxyethyl methacrylate(HEMA). The nucleation mechanism and growth process of polymer latex particles were investigated. The effects of HEMA on diameter of the latex particles and monomer conversion were discussed. The elemental analysis and XRD results showed that HEMA was dispersed mainly on the surface of the latex particles, it could stabilize the latex particles and lead the nucleation. The nucleation of particles occurs likely by homogeneous nucleation mechanism. The diameter of the latex particles decreased and the conversion increased, as HEMA′s dosage increased.
