Preparation Of Electrophoretic Particle And Its Application In E-Ink

Electronic ink was a panel display technology, which ultilizes electrophoretic movement of particles in the microcapsules to realize display. After the first white-and-black E-Ink display was commercialized successfully, electronic ink display has been focused on the preparation of color electronic ink now. According to color electronic ink technologies such as color filter method, electrophoretic mobilities controling method and subpixels method, the new color electrophoretic particles were needed. In this paper, a series of color electrophoretic particles were prepared. And they were applied in electronic ink and good results were obtained.The electrophoretic particles of phthalocyanine Green G and Hansa yellow 10G which were modified with hyperdispersants were prepared by ball milling. Among these particles, phthalocyanine Green G modified with CH-5/CH-11B, Hansa yellow 10G modified with CH-5/CH-22 and CH-6/CH-22 had good performances. Dispersibility TD% was 99.9%, 99.8% and 99.8% respectively. Electrophoretic mobility was -0.08082 cm2V-1s-1,-0.09954 cm2V-1s-1 and-0.10110 cm2V-1s-1 respectively. Electronic ink microcapsules containing Phthalocyanine Green G and hansa yellow 10G electrophoretic particles modified with hyperdispersants were prepared respectively. Results revealed that they had reversible electric response in the microcapsules in the electric field of E=50V/mm.Pink polymer electrophoretic particles containing a red dye-oil red G, were prepared by dispersion polymerization of styrene, divinylbenzene in ethanol medium with polyvinylpyrrolidone as stabilizer, 2,2'-azobis(2-methylpropionitrile) as initiator. Methylacrylic acid was grafted to the surface of the polymer particle to introduce the electric charge to it. The particle size of polymer electrophoretic particles was in the range from 0.5μm to 1.5μm. The density was 1.07g/cm3 and the electrophoretic mobility was - 0.03942cm2V-1s-1. Electronic Ink microcapsules containing the polymer particles were prepared by coacervation. Results showed that pink polymer particles had reversible electric response in the microcapsules in the electric field of E=75V/mm.The polymer particles with carboxyl group in their surface were prepared by dispersion polymerization of styrene, divinylbenzene and methylacrylic acid. Yellow polymer electrophoretic particles, in which chromophoric group (p-chloro-o-nitroaniline) were attached on the surface of polymer particles, were prepared by functional reaction. The particle size of the yellow polymers was in the range from 1.5μm to 2.0μm. The density was 1.08g/cm3 and the electrophoretic mobility was - 0.05236 cm2V-1s-1 and - 0.05218cm2V-1s-1. Electronic Ink microcapsules containing the yellow polymer particles were prepared by coacervation. Results showed that yellow particles had reversible electric response in the microcapsules in the electric field of E=75V/mm.The hydrophobic SB570-TiO2 particles were prepared by surface-modifying with a silane coupling agent, methacryloylpropyltrimethoxysilicane (SB570). Core-shell composite particles with modified-TiO2 particles as core, the copolymer of styrene and divinylbenzene as shell were prepared by dispersion polymerization. Electronic Ink microcapsules containing the polymer particles were prepared by coacervation. Results showed that the core-shell composite particles had no electric response, which could be used as grounding particles for E-Ink.