Design and synthesis of multicolor electrochromic polymers based on oligoaniline and viologen/phenothiazine groups

We report the design and synthesis of novel electroactive polymers bearing oligoaniline and viologen/phenothiazine groups through electrochemistry-assisted hydrolytic crosslinking reaction. The resulting polymers exhibit multicolor electrochromic behavior featuring remarkable switching durability. [Display omitted] •Polymers bearing oligoaniline and viologen/phenothiazine groups are prepared.•The polymers exhibit multicolor electrochromic behavior due to synergistic effect.•Fascinating switching durability is also disclosed in the electrochromism. Multicolor electrochromic polymers have attracted great attention and interest owing to their potential applications in multicolor displays, intelligent electronic devices, and smart visualized sensors. Herein, we prepared new electrochromic polysiloxanes by chemically coupling oligoaniline groups with cathodically colouring viologen and/or anodically colouring phenothiazine groups, respectively. Due to the combined effect and synergistic effect of paired anodically colouring oligoaniline and cathodically colouring viologen, the resulting polysiloxane exhibits multicolor electrochromic behavior switching from purple to transparent grey, to light green, finally to blue. As the oligoaniline units coupled with anodically colouring phenothiazine groups, the resultant polysiloxane also demonstrates multicolor electrochromic behavior changing from transparent grey to light green, to gray-blue, to brown and finally black purple. Furthermore, good switching durability has also been revealed during the electrochromic measurements, because of their robust network molecular structure and covalent bonding to the substrate.