Redox Conversions of Poly(3,4-ethylenedioxythiophene) and Its Copolymer with Bithiophene in Aprotic Media of Different Donor Capability

Electrochemical oxidation and reduction of poly(3,4-ethylenedioxythiophene) in solvents of different donor capabilities is studied by cyclic voltammetry. The reversibility of the anodic process is dependent on the solvent viscosity. The polymer's anodic oxidation is presumably limited by the rate of removal of solvent molecules released during the desolvation of anions-dopants of the polymer matrix. The reversibility of the polymer's cathodic reduction improves with increasing donor capability of the solvent. A residual charge of both signs discovered in the polymer points to its chemical heterogeneity. An in-principle feasibility of copolymerization of 3,4-ethylenedioxythiophene and bithiophene is shown.