Colored nanoparticles dispersions as electronic inks for electrophoretic display

Phthalocyanine green (CuPcCl) nanoparticles was successfully prepared by anti-solvent recrystallization method and combined with in situ modification to improve the electrophoretic properties and dispersion ability in organic medium. The produced particles were characterized by SEM, FT-IR and ζ-potential test. It was found that the particles exhibited 120 nm with spherical shape and narrow size distribution when the modifier was mixture of CTAB and PVP. Sedimentation ratio of the prepared CuPcCl particles in tetrachloroethylene was nearly down to zero within 30 days and the ζ-potential was 26.8 mV. In addition, stable TiO2/C2Cl4 dispersion was prepared by coated TiO2 surface with trimethoxyoctylsilane. The sedimentation ratio of the modified TiO2 was nearly 7.6% within 30 days, and the ζ-potential value was −28.9 mV. The particle size was about 300 nm with spherical morphology. The results demonstrated that green CuPcCl and white TiO2 dispersions were suitable as electronic ink and showed potential value in the application of electrophoretic display.