A soluble conducting polymer of 4-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)benzenamine and its multichromic copolymer with EDOT

Here we report the synthesis of a monomer, 4-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)benzenamine (SNS-NH2) produced by the reaction of 1,4-di(2-thienyl)-1,4-butanedione and benzene-1,4-diamine. This monomer was electrochemically polymerized in the presence of LiClO4, NaClO4 (1:1) as the supporting electrolyte in acetonitrile. Copolymerization in the presence of 3,4-ethylenedioxythiophene (EDOT) was achieved in acetonitrile NaClO4/LiClO4 (0.1 M:0.1 M) solvent-electrolyte couple. Resulting homopolyrner and copolymer were characterized by means of cyclic voltammetry, Fourier transform infrared spectroscopy, nuclear magnetic resonance, scanning electron microscopy and ultraviolet-visible spectroscopy. Spectroelectrochemistry analysis of homopolymer, P(SNS-NH2), reflected electronic transitions at 376 and 650 nm indicating pi-pi* transition and polaron band formation, respectively. The polymer has an electronic bandgap of 2.12 eV with a yellow color in the fully reduced form and a blue color in the fully oxidized form. Switching ability of the homopolymer was evaluated by kinetic studies upon measuring the %T as 20.7% at the maximum contrast point. Copolymer revealed multichromic property with five different colors at different applied potentials. Colorimetry studies for P(SNS-NH2-co-EDOT) proved that it is possible to provide fine tuning of these colors by varying applied potential during synthesis. Dual-type complementary colored electrochromic devices (ECD) using P(SNS-NH2-co-EDOT)/poly(3,4-ethylenedioxythiophene) (PEDOT) in sandwich configuration were constructed. Spectroelectrochemistry, switching ability and optical memory of the electrochromic devices were investigated. (c) 2067 Elsevier B.V. All rights reserved.