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 ∼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 ∼750 and ∼650 ms, respectively, when +1.4 and -1.4V/μm DC field were alternately applied to the front electrode.