Preparation of a multicolored reflective electrochromic display based on monodisperse polymeric microspheres with N-substituted viologen pendants

This article describes the preparation of multicolored reflective electrochromic displays (R-ECDs) through the control of the substituents on viologen molecules. Cyanophenyl, salicylic, and alkyl groups were introduced onto 4,4'-bipyridine. The synthesized viologen moieties were reacted with methyl chloride functional groups on polymeric microspheres, which were prepared by seeded polymerization. Then, R-ECD cells were fabricated by the placement of a mixture of the viologen-modified polymeric microspheres and an electrolyte between sandwiched indium tin oxide glasses. The R-ECDs showed an inherent white background without potential because the micrometer-range particles scattered the light, and the viologen was in a bleached state. From spectrophotometric results and visual appearances, it was confirmed that the devices showed red, green, and blue colors with respect to cyanophenyl-, salicylic-, and alkyl-substituted viologen pendants when 2.7 V was applied to the device. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008