Monodisperse, controlled micron-size dye-labeled polystyrene particles by two-stage dispersion polymerization

Monodisperse controlled micron-sized colored polystyrene particles have been prepared by two-stage dispersion copolymerization with polymerizable dyes. These polymerizable dyes have a methacrylate moiety for copolymerization with styrene and suitable spacers between the dye nucleus and the methacrylate function to promote the solubility of the dye. In the past, various research groups have found that when they added a dye-comonomer to a traditional dispersion polymerization recipe, they obtained poor results. The final particle size changed significantly; and the size distribution became broader. In the two-stage method, we defer the addition of the dye-comonomer until the nucleation stage is complete. These dyes become incorporated into the particles without disturbing the final particle size and size distribution.