Electrochemical and Electrochromic Properties of Polymers Based on 2,5-di(2-thienyl)-1H-pyrrole and Different Phenothiazine Units

Three new 2, 5-di(2-thienyl)-1H-pyrrole(DTP) derivatives, 10-[4-(2,5-Di- thiophen-2-yl-pyrrol-1-yl)-phenyl]-10H-pheno-thiazine (TPPT), 10-[4-(2,5-Di- thiophen-2-yl-pyrrol-1-yl)-phenyl]-10H-phenox azine (TPPO) and 10- [4-(2,5 -Di-thiophen-2-yl-pyrrol-1-yl)-phenyl]-10H-acridin-9-one (TPAO), were synthesized and characterized. TPPT and TPPO showed similar absorption and emission feature owing to similar chemical structure, TPAO displayed bathochromic-shift for both absorption and emission feature due to the existence of ketone group. All the monomers could be electropolymerized to form their polymer film on the electrode surface via oxidative coupling reactions of DTP units. PTPPT film showed yellow-green, green and purple red color upon different applied potentials. PTPPO and PTPAO films exhibited green and yellow at the neutral state, respectively, and turned into the similar violet color for the oxidized state. Moreover, the copolymer P(TPPT/EDOT) and P(TPAO/EDOT) not only showed obvious color change(red, yellow, green and blue), but also possessed better electrochemical stability.