Preparation of colored electrophoretic nanoparticles by emusifier-free emulsion polymerization and reactive dyeing

Colored, electrophoretic polymer nanoparticles of poly (styrene-co- divinylbenzene-co-vinyl acetate) [poly(St-co-DVB-co-VAc)] were prepared by emulsifier-free emulsion copolymerization and reactive dyeing. The emulsifier-free emulsion polymerization of styrene, divinyl benzene and vinyl acetate was carried out at 70 °C for 20 hrs to obtain monodisperse polymer nanoparticles of poly (St- co- DVB- co-VAc) with an average diameter of 180-200 nm. These nanoparticles were transformed into poly(styrene-co-divinylbenzene-co- vinyl alcohol) [poly (St-co-DVB-co-VA)] nanoparticles through the saponification reaction. The poly(St-co-DVB-co-VA) nanoparticles were treated with reactive dyes to obtain the colored, monodisperse electrophoretic nanoparticles, and their morphology and surface charge were characterized by scanning electron microscopy, differential scanning calorimetry, UV/Vis absorbance and zeta-potentiometry.