Preparation and characterization of Fe3O4/SiO2 particles for dual-particle electrophoretic display

In order to prepare metal-oxide-pigment based electrophoretic particles with good suspension stability in the low dielectric medium for electrophoretic display application, ferroferric oxide/silicon oxide (Fe3O4/SiO2) composite particles were prepared via in situ sol–gel method. The transmission electron microscopy (TEM)/scanning electron microscope (SEM) images present the multi core–shell morphology for the Fe3O4/SiO2 particles and the average particle size is 250–350 nm. It was found that the Fe3O4/SiO2 composite particles own lower density than that of Fe3O4 because of SiO2 encapsulation and can suspend stably in tetrachloroethylene after OLOA treatment. Zeta potential and electrophoretic mobility of the OLOA treated Fe3O4/SiO2 composite particles in tetrachloroethylene were measured to be 24.2 mV and 3.80 × 10−10 m2/V s, respectively. The dual-particles electrophoretic dispersion containing OLOA treated Fe3O4/SiO2 composite particles and TiO2 grafted with polymer can show white/black image under low DC field.