Synthesis and electrochromic properties of triphenylamine containing copolymers: Effect of π-bridge on electrochemical properties

In this study, a series of benzotriazole (BTz) and triphenylamine (TPA)-based random copolymers; poly4-(5-(2-dodecyl-7-methyl-2H-benzo[d][1,2,3]triazol-4-yl)thiophen-2-yl)-N-(4-(5-methylthiophen-2-yl)phenyl)-N-phenylaniline (P1), poly4′-(2-dodecyl-7-methyl-2H-benzo[d][1,2,3]triazol-4-yl)-N-(4′-methyl-[1,1′-biphenyl]-4-yl)-N-phenyl-[1,1′-biphenyl]-4-amine (P2), and poly4-(5′-(2-dodecyl-7-(5-methylthiophen-2-yl)−2H-benzo[d][1,2,3]triazol-4-yl)-[2,2′-bithiophen]-5-yl)-N-(4-(5-methylthiophen-2-yl)phenyl)-N-phenylaniline (P3) were synthesized to investigate the effect of TPA unit and π-bridges on electrochemical and spectroelectrochemical properties of corresponding polymers. The synthesis was carried out via Stille coupling for P1, P3, and Suzuki coupling for P2. Electrochemical and spectral results showed that P1 has an ambipolar character, in other words it is both p-type and n-type dopable, whereas P2 and P3 have only p-doping property. Effect of different π-bridges and TPA unit on the HOMO and LUMO energy levels, switching time, and optical contrast were discussed. All polymers are promising materials for electrochromic devices. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 537–544