Fabrication of charged particles for electrophoretic display

Preparation conditions of nano-size cationically charged particles (TiO2) were studied for application to electrophoretic display. It was found that highly charged TiO2 particles could be prepared by milling 1.0 g of TiO2 particles, 0.5 g of silane additive as a charge controlling agent and 0.5 g of dispersant in 100 mL of cyclohexanone as a suspension fluid for 8-10 h using pot mill, followed by treatment with 0.4 g of acetic acid. The zeta potential and mobility of white (TiO2) charged particles were measured to be 63.76 mV and 3.11 × 10−5 cm2/V s, respectively. The e-paper display panel fabricated with charged TiO2 particles exhibited low threshold voltage (10 V) and 5.32/1 contrast ratio at 30 V.