Electro-Optic Response Characteristics of a Dual Particle Electrophoretic Display System

Electrophoretic nanoparticles of polystyrene (PS)-encapsulated red pigments were prepared by an emulsifier-free in-situ emulsion polymerization method and the zeta potential of the red nanoparticles was +190 mV. We demonstrated a dual particle electrophoretic display (DPEPD) system with red and white contrast using the positively charged PS-encapsulated red pigment particles and the negatively charged white particles of rutile titanium dioxide. The scattering light intensity ratio of the white and red images was similar to 1.7 but we could clearly observe the reversible color change between red and white when the polarity of the applied electric field was switched. 4 The turn-on and turn-off response times of the device were measured to be similar to 750 and similar to 650 ms, respectively, when +1.4 and -1.4 V/mu m DC field were alternately applied to the front electrode.