A Novel Modification of Copper (II) Phthalocyanine Particles towards Electrophoretic Displays

Electrophoretic display (EPD) is a popular display technology in recent years. The core of the EPD is electrophoretic particles, and its Zeta potential has an important impact on EPDs. In this work, a method using pyrrolidine mono ionic liquid was proposed to improve the Zeta potential of electrophoretic particles: Copper (II) phthalocyanine pigment was modified with mono ionic liquid 1-Butyl-1-methylpyrrolidinium bromide. The characterization results show that the mono ionic liquid had been successfully coated on pigment particles. At the same time, the dispersion and stability of particles were improved. The modified Copper (II) phthalocyanine pigment could be stably dispersed in tetrachloroethylene for more than 20 days. The Zeta potential increased from 32.42 mV to 49.91 mV, increasing by 53.95%. Finally, the prepared blue electrophoretic particles were compounded with white titanium dioxide to prepare blue and white dual-color electrophoretic dispersion, and then an EPD cell was designed to test its performance. The results show that the prepared electrophoretic dispersion can realize reversible reciprocating motion. Therefore, because of the unique structure and properties of pyrrolidine mono ionic liquids, the blue nanoparticles prepared with pyrrolidine ionic liquids as charge control agents in this study can be used as excellent candidate materials for EPD.