Preparation and electrochromic properties of polyamides based on 3,4-dimethylthieno[2,3-b]thiophene

Based on the performance of improving the stabilities and coloring efficiencies of triphenylamine polymers, this paper separately synthesized different diamines and 3,4-dimethylthieno[2,3-b]thiophene-2,5-dicarboxylic acid, and the electrochromic functions of the polymer films were studied on indium-tin oxide glass (ITO) glass. The polymers had a thiophene group, which was rich in pi-electrons and conducive to molecular stability, and showed good stabilities. Ultraviolet spectrum showed that all the six polymers had a wide absorption band in the neutral range of 200-700 nm. Electrochromic analysis showed that the six kinds of polymer films all showed reasonable optical contrast, short response time and low band gap in the infrared spectrum range of 200-1000 nm. Among them, the film formed by PAD2 on ITO glass had better electrochromic properties, longer bleaching response time (t(c) = 1.3 s, t(b) = 4.1 s), PAD3 had better coloration efficiency (214 cm(2) C-1).