Electrochromism and Nonvolatile Memory Device Derived from Triphenylamine‐Based Polyimides with Pendant Viologen Units

Three novel solution‐processable polyimides containing triphenylamine and pendant viologen moieties are prepared from the newly synthesized diamine and three commercially available dianhydrides. The thermally stable polyimide with strong donor–acceptor charge‐transfer possesses write‐once read‐many‐times memory behavior with excellent operation stability. The obtained multicolored electrochromic polymer films reveal ambipolar electrochemical behavior with high optical transmittance contrast of coloration changed from transmissive neutral state to the cyan/magenta/yellow redox states, implying great potential for application in smart window and displays.