Electrophoretic response of poly(methyl methacrylate) coated TiO2 nanoparticles

A microcapsule-based electronic ink display technique, which uses the microencapsulation of electrophoretic dispersion, is being developed for direct-view portable displays. Microcapsules of titanium dioxide (TiO2) electrophoretic nanoparticle suspension were prepared using amino precondensates via in-situ polymerization. The amino prepolymers were synthesized from melamine-urea formaldehyde resin at 60 °C. However, since TiO2 has a relatively high density (4.28 g/cm3), the density mismatch causes severe sedimentation problem in the suspended media. In order to lower its density, TiO2 was coated with poly(methyl methacrylate) via a dispersion polymerization method prior to being used for an electronic ink material. In order to improve their mobility, a charge control agent was also added to the suspension of synthesized nanoparticles in the dielectric medium. Electrophoretic mobility of the synthesized particles was investigated via electrophoretic light scattering. The morphology of the synthesized microcapsule was also characterized by optical microscopy, and scanning electron microscopy.