Multichromic benzimidazole-containing polymers: Comparison of donor and acceptor unit effects

This study reports a comparative study on electrochromic properties of two donoracceptordonor (DAD)-type polymers namely poly(2-heptyl-4,7-di(thiophen-2-yl)-1H-benzo [d]imidazole) (BImTh) and poly(4,7-bis(2,3-dihydrothieno[3,4-b] [1,4]dioxin-5-yl)-2-heptyl-1H-benzo[d]imidazole) (BImEd). DAD-type monomers were polymerized electrochemically on indium tin oxide-coated glass slides to determine the optical properties of the polymers. Electrochemical rho-doping experiments were performed to determine the band gap and absorption band values of the polymer films at different redox states. Polymerization of BImTh and BImEd yields multichromic polymers. Donor and acceptor effects are studied by comparing the PBImEd and PBImTh with corresponding benzotriazole derivatives. (c) 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012