High‐quality freestanding flexible poly(5‐(2, 3‐dihydrothieno[3, 4‐b][1, 4]dioxin‐5‐yl)‐1H‐indole) film: Electrosyntheses, characterization, and optical properties. Issue 2 (22nd August 2018) - Wang, R.
ABSTRACT: The electron‐donating substituted indole is generally difficult to be polymerized into high‐quality film. The electrochemical polymerization of the electron‐donating 3, 4‐ethylenedioxythiophene (EDOT)‐monosubstituted indole may be a challenge. Herein, we designed and synthesized a novel fluorescent comonomer based on the combination of indole and EDOT groups, namely, 5‐(2, 3‐dihydrothieno[3, 4‐ b ][1, 4]dioxin‐5‐yl)‐1 H ‐indole (EDTI), and subsequently electrodeposited into flawless freestanding flexible poly(5‐(2, 3‐dihydrothieno[3, 4‐ b ][1, 4]dioxin‐5‐yl)‐1 H ‐indole) (PEDTI) film with a resistance of 60 MΩ/cm in CH2 Cl2 containing 0.1 M Bu4 NBF4 . Electrochemical results showed that the oxidation onset potential of EDTI was at 0.8 V vs Ag/AgCl, which was lower than those of indole (0.96 V vs Ag/AgCl) and EDOT (1.35 V vs Ag/AgCl). FTIR spectra indicated that the polymerization of EDTI occurred at the 5‐position on thiophene ring and 2, 3‐positions on indole ring, forming the crosslinking polymer film. The colors of as‐prepared PEDTI could switch reversibly from purple to brown under applied potentials of 1.3 and −1.3 V, which were distinctly different from those of polyindole, poly(3, 4‐ethylenedioxythiophene) (PEDOT), and poly(EDOT‐bis‐substituted indole) (PETI). Fluorescence spectral studies revealed that the comonomer and corresponding polymer were good blue‐green light emitters. These results implied that PEDTI had potential applications for photoelectric devices such as electrochromic devices, light‐emitting diodes, and fluorescence sensors. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2019, 136, 47016. Abstract :