Surface modification of titanium dioxide for electrophoretic particles

Abstract

To prepare stable electrophoretic ink (E Ink) needs color particles to be uniformly dispersed in the organic medium. Thus, t-he modification of inorganic particle surface is required. In this paper, Titanium dioxide modified by alumina has been studied. The surface composition and structures of modified particles have been characterized by X-ray photoelectron spectrometer (XPS), X-ray diffractometer (XRD) and Fourier transform infrared spectrometer (FT-IR). The dispersibility and electrophoretic mobility of these particles in tetrachloroethylene (TCE) have been investigated by laser particle size analyzer, static sedimentation and electrophoretic instrument. Effects of temperature, pH value and stirring rate on the dispersibility and the charge property of samples have been discussed. The results indicate the settle time of modified TiO₂ can last 120 h with the response time of 35 s under the optimized modifying conditions, in which temperature is 85°C–90°C, pH is 8–9 and stirring rate is 800 r · min^-1. The dispersibility and electrophoretic mobility have been significantly improved, which means that the modified TiO₂ is suitable for electrophoretic ink particles.