Soap-free emulsion polymerization was extended to reparation of monodisperse poly(methyl methacrylate) (PMMA) particles incorporating rhodarnine 6G (MG) fluorescent molecules. The polymerization was conducted in the presence of an anionic monomer, p-styrenesulfonate (NaSS), which improved dispersion stability of the polymer particles. NaSS concentrations was ranged up to 2 mol/m(3) H2O in the polymerization at 0.5 kmol/m(3) H2O methyl methacrylate (MMA) monomer and 5 mol/m(3) H2O potassium persulfate (KPS) initiator for R6G concentrations from 0.1 to 10 mol/m(3)-polymer. At R6G concentrations lower than 1.0 mol/m(3)-polymer, PMMA particles were highly monodisperse and incorporated most R6G molecules. The average sizes of PMMA particles were in a rage of 160-300 nm, and decreased with the concentration of NaSS. The high monodispersity of the particles enabled the fabrication of colloidal crystals of the particles with a vertical deposition method. (c) 2005 Elsevier Inc. All rights reserved.