Base inhibited oxidative polymerization of 3,4-ethylenedioxythiophene with iron(III)tosylate

Very high conductivities (>1000 S/cm) were obtained in poly(3,4-ethylenedioxythiophene) films oxidized with Fe(III)tosylate when the acidity during the polymerization process was controlled using a basic inhibitor. The best results were obtained with pyridine as inhibitor. The films could either be polymerized from a solution of 3,4-ethylenedioxythiophene (EDT), Fe(III)tosylate and pyridine or by vapor phase polymerization (VPP) of EDT on a surface coated with Fe(III)tosylate and pyridine. By incorporating non-conducting adhesive (up to 75% vol.) in the vapor phase polymerized PEDT system, films with activation energy of 1/3 the value of pure PEDT, were obtained. The reason for this phenomenon could not be explained by changes in the PEDT structure investigated with grazing incidence X-ray diffraction.