Black inorganic pigment modified with poly(styrene-co-acrylonitrile) was fabricated via dispersion polymerization, and then the synthesized hybrid nanoparticles were examined by SEM to confirm their morphology, while their density and size were studied using a gas pycnometer and electrophoretic light scattering apparatus, respectively. We also confirmed their chemical structure and coated state via FT-IR and TGA. Electrophoretic characteristics including the zeta potential were examined via an electrophoretic light scattering apparatus, while the movement of particles was directly observed by an optical microscopy under an electric field applied. The hybrid nanoparticles were confirmed to possess an electrophoretic property as a potential candidate for the microcapsule-type electrophoretic display.

To prepare electrophoretic black particles with good suspension stability in the low dielectric medium for the electrophoretic display application, black pigment (B444) as a core material and polystyrene (PS) as a shell material were prepared via dispersion polymerization of styrene, and then the fabricated B444/PS composite particles were positively charged with 2-(methacryloyloxy) ethyl trimethylammonium chloride. Morphology of the B444/PS core-shell particles was observed by scanning electron microscopy, while their chemical structure was confirmed via an FT-IR. Maximum values of the electrophoretic mobility and zeta potential observed by dynamic light scattering reach 4.46 x 10(-6) m2/Vs and 30.23 mV in a low dielectric medium, respectively. The resulting B444/PS particles also showed good electrophoretic movement in the B444/PS particle embedded microcapsules. Therefore, it can be applied in the dual-particle electrophoretic dispersion together with negative charged TiO2, showing black and white images.