Synthesis and Characterization of Novel Triphenylamine-Containing Electrochromic Polyimides with Benzimidazole Substituents

Kuangguo Yan; Haiquan Chen; Chenjie Zhu; Zhao Ke; Dongwu Li; Mengxia Wang; Fengna Dai; Youhai Yu

doi:10.3390/molecules28052029

Synthesis and Characterization of Novel Triphenylamine-Containing Electrochromic Polyimides with Benzimidazole Substituents

Molecules. 2023 Feb 21;28(5):2029. doi: 10.3390/molecules28052029.

Authors

Kuangguo Yan¹, Haiquan Chen¹, Chenjie Zhu¹, Zhao Ke¹, Dongwu Li¹, Mengxia Wang¹, Fengna Dai¹, Youhai Yu¹

Affiliation

¹ Center for Advanced Low-Dimension Materials, State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Material Science and Engineering, Donghua University, Shanghai 201620, China.

Abstract

Two novel electrochromic aromatic polyimides (named as TPA-BIA-PI and TPA-BIB-PI, respectively) with pendent benzimidazole group were synthesized from 1,2-Diphenyl-N,N'-di-4-aminophenyl-5-amino-benzimidazole and 4-Amino-4'-aminophenyl-4″-1-phenyl-benzimidazolyl-phenyl-aniline with 4,4'-(hexafluoroisopropane) phthalic anhydride (6FDA) via two-step polymerization process, respectively. Then, polyimide films were prepared on ITO-conductive glass by electrostatic spraying, and their electrochromic properties were studied. The results showed that due to the π-π* transitions, the maximum UV-Vis absorption bands of TPA-BIA-PI and TPA-BIB-PI films were located at about 314 nm and 346 nm, respectively. A pair of reversible redox peaks of TPA-BIA-PI and TPA-BIB-PI films that were associated with noticeable color changed from original yellow to dark blue and green were observed in the cyclic voltammetry (CV) test. With increasing voltage, new absorption peaks of TPA-BIA-PI and TPA-BIB-PI films emerged at 755 nm and 762 nm, respectively. The switching/bleaching times of TPA-BIA-PI and TPA-BIB-PI films were 13 s/16 s and 13.9 s/9.5 s, respectively, showing that these polyimides can be used as novel electrochromic materials.

Keywords: benzimidazole; electrochromic materials; polyimide films; two-step polymerization.

Grants and funding

The APC was funded by Research Startup program of Donghua University, Grant/Award Number: 285-07-005702; The Key-Area Research and Development Program of Guangdong Province, Grant/Award Number: 2020B010182002.