Synthesis and electrochromic properties of a symmetric polythiophene derivative: Decanedionic acid bis-(2-thiophene-3-yl-ether)ester and its copolymer with thiophene

Here we describe the electrochemical homopolymerization and copolymerization of decanedionic acid bis-(2-thiophene-3-yl- ether)ester (DATE) in the presence of thiophene. Tetrabutylammonium tetrafluoroborate (TBAFB) was utilized as the supporting electrolyte in acetonitrile (ACN) /borontrifloride ethylether (BFEE) solvent mixture (8:2D, v/v). Electrochemical homopolymerization of DATE and copolymerization with thiophene were studied by cyclic voltammetry (CV). Conducting polymers were characterized by Fourier Transform Infrared (FT-IR) and Thermal Analyses. The morphologies of electrochemically synthesized P(DATE) and P(DATE-co-Th) thin films were analyzed by Scanning Electron Microscopy (SEM). Electrical conductivities were measured by the four-probe technique. Spectroelectrochemical behaviors of P(DATE) and P(DATE-co-Th) films were investigated by UV-Vis Spectrophotometer. Homopolymer revealed color changes between brownish Yellow and blue, whereas copolymer revealed changes between orange and blue in reduced and oxidized states respectively. Switching ability of the polymers was investigated via kinetic study upon measuring the % transmittance (%T) at the maximum contrast point. Results implied that copolymerization is a valuable approach to achieve the desired electrochromic properties.