Nissan Motor Company Limited

Takao Kase

Yasuhiko Ohsawa

Takeshi Miyamoto

Mikio Kawai

Shigenori Kazama

Masazumi Ishikawa

Teruko Yoshimoto

Mikio Ura

Yoshiko Maeda

The disclosure relates to a novel polymer which is made up of repeating units of N,N,N'N'-tetrapheny-p-phenylenediamine. This polymer is thermoplastic and is soluble in industrially usable organic solvents. The polymer acquires high conductivity by doping with an electron acceptor. The polymer becomes insoluble in organic solvents when it is once doped with an electron acceptor and then dedoped, so that the polymer can be used as an active electrode material in electrolytic devices using an organic solvent. The polymer has electrochromic properties and undergoes two-stage oxidation and two-stage reduction to assume three differently stable states. The polymer exhibits pale yellow color in its reduced state, green color in the first-stage oxidized state and dark blue color in the second-stage oxidized state.

Electrochromic polymer comprising

An electrochromic device having two electrochromic layers respectively formed on oppositely arranged two electrodes and containing an electrolyte such as a solution of an alkali metal salt in an organic solvent which fills up the gap between the two electrodes. The electrochromic layers are formed of an electrochromic material which can alternately and stably exist in three different oxidation states and assumes three different colors in its respective oxidation states such that there is a clear contrast between the color of this material in its normal or intermediate oxidation state and a composite color given by superposition of the color in the highest oxidation state on the color in the lowest oxidation state. Prussian blue is a preferred example of such an electrochromic material, on condition that an adequate amount of water be present in the electrolyte solution or, alternatively, that the Prussian blue layers be pretreated to substitute alkali metal cation for Fe.sup.3+ interstitially existing in the crystal lattice of Prussian blue.

Electrochromic device

Growing community of inventors

Yokosuka, Japan

Takao Kase