Electropolymerization of 3,4-Ethylenedithiathiophene in the Green Binary Solvent System of Water and Ethanol

The electrosynthesis of poly(3,4-ethylenedithiathiophene) (PEDTT), which is the sulfur analogue of the well-known poly(3,4-ethylenedioxythiophene) (PEDOT), is investigated in green binary solvent system of deionized water and anhydrous ethanol (1:1 by volume) contained poly(sodium-p- styrenesulfonate) (PSSNa) as the surfactant and LiClO4.3H2O as supporting electrolyte . The polymer obtained from this medium showed good electrochemical behavior, stability, electrochromic properties and could be partly dissolved in dimethylsulfoxide, tetrahydrofuran, chloroform, etc. Electrochemical impedance studies were performed on Pt/PEDTT/electrolyte system. From the Nyquist plots of the PEDTT film, the electroactivity of the polymer starts to increase from 1.0 V. FT-IR and UV-vis-NIR spectra indicated that the polymerization of monomer occurred mainly at 2,5 position. Cyclic voltammetry and spectroelectrochemistry studies demonstrated that PEDTT can be reversibly oxidized and reduced accompanied by obvious color changes from grass green to golden brown, these properties indicate that the polymer showed favorable electrochromic performance. Fluorescent spectral studies indicated that the polymer was a green-light emitter. TG and DTG analyses showed that the as-formed PEDTT films had good thermal stability.