Abstract: Black pigment nanoparticles were modified with a series of monomers with different polarities by radical grafting polymerization, and the effects of these polymer coating layers on the dispersion stability of copper chromite nanoparticles used in electrophoretic medium were examined by transmittance method. The results show that the stabilization time of particles in nonaqueous medium at least has increased 5 times after polymer modification, and the longer the side chain of monomer, the stabler the particles. When the monomer with an alkyl chain containing more than 4 carbon atoms, the corresponding polymer layers will impart good dispersibility to particles. The final black/white electrophoretic display has a response time of less than 1 s and contrast of (4~5):1 under a bias voltage of 5 V. The present results will provide a guideline for polymer modification of electrophoretic particle and theoretical foundation for improving electrophoretic medium stability and lifetime of electrophoretic display.

Key words: electrophoretic display, dispersion stability, non-aqueous medium, polymer modification, UV transmittance

摘要： 采用自由基接枝聚合法，将不同极性的单体修饰在黑色无机颜料颗粒表面，以紫外透光率法为主要表征手段，考察了聚合物包覆层的组成结构对颗粒在电泳体系中分散稳定性的影响. 结果表明，聚合物修饰后颗粒稳定时间至少提高5倍，且随所用包覆单体侧链长度增大而增大. 当单体支链的碳原子数大于4时，颗粒能很好地长时间分散在非水体系中. 所制黑白电泳显示器在5 V电压下，响应时间小于1 s，对比度达(4~5):1. 本结果为提高缺乏理论研究的电泳显示体系的分散稳定性和电泳显示效果及使用寿命提供了研究基础.

关键词: 电泳显示器, 分散稳定性, 非水体系, 聚合物修饰, 紫外透光率