Preparation of high efficiency hollow TiO2 nanospheres for electrophoretic displays

In this paper, we reported an effective approach for fabrication of hollow TiO2 as electrophoretic particles. In this approach, the copolymer was first synthesized via emulsifier-free emulsion polymerization using the cationic initiator. Subsequently, the core-shell structure was successfully formed by deposited titanium dioxide and calcination resulted in spherical shells composed of a dense arrangement. The whole process didn't require any surfactant or surface modification. The result showed that high efficiency hollow TiO2 nanospheres were obtained with the average diameter of approximately 230 nm. Furthermore, we investigated freeze drying process of core-shell structure: this kind of process could effectively reduce the fragmentation and break during the calcination. To the best of our knowledge, using freeze drying process to prevent breaking the hollow spheres was seldom mentioned in related paper. Without extra surface modification, low density hollow TiO2 nanoparticles were dispersed into medium then filled into micro-cup device. The obtained high efficiency hollow TiO2 nanospheres were fit for electronic paper display at low voltage. (C) 2011 Elsevier B.V. All rights reserved.