Titanium dioxide (TiO2) with appropriate characteristics of high refractivity and excellent whiteness, was modified via a coating process with poly(methyl methacrylate) in order to reduce density mismatch between TiO2 and dielectric medium, to obtain good dispersion stability. Microcapsule, which contains suspended TiO2 nanoparticles in a dielectric medium, was then synthesized for the electrophoretic display application. In a coating process, the TiO2 nanoparticles were treated with dodecylbenzensulfonic acid to modify their surface characteristics hydrophobic. The shell materials of microcapsules were composed of amino precondensates through in situ polymerization. Anionic polymeric surfactant, poly(ammonium styrenesulfonic acid), was used to keep the emulsion stable. We examined both shape and size of the microcapsules via optical microscope and surface morphology of the modified TiO2 nanoparticles with PMMA using scanning electron microscope (SEM). Electrophoretic mobility of the composed nanoparticles dispersion in a low dielectric medium was also investigated via an electrophoretic light scattering analyzer. (c) 2005 Elsevier B.V. All rights reserved.