Morphological and impedance studies on electropolymerized 3,4-(2,2-dibenzylpropylenedioxy)thiophene nanostructures on micron sized single carbon fiber

Micron sized single carbon fibers were cyclovoltammetrically coated with poly[3,4-(2,2-dibenzylpropylenedioxy)thiophene] resulting in a nanofiber network at the surface. The method provides conjugated polymer nanostructures covalently and uniformly bound to micron sized substrates. When the electropolymerization is carried out with different electrolytes in acetonitrile the dopant influences the structure of the coating layer what is proved by electrochemical impedance spectroscopy and electron microscopy. Electrodes based on poly[3,4-(2,2-dibenzylpropylenedioxy)thiophene] on single carbon fiber microelectrodes (SCFMEs) prepared in Bu4NPF6/ACN show the best capacitance performance due to their higher surface area. The improvement is attributed to the formed nanofiber network structure which results in a more efficient charge transport and collection.Impedance spectra show the typical form of ZIM vs. ZRE curves for transmission-line at a frequency of 10 Hz, with transition to almost pure capacitive behavior up to 10 MHz. Equivalent circuit modeling was simulated for the electrolyte/polymer film/SCFME system. A good agreement was achieved for the calculated capacitances in comparison with the experimental EIS measurement results.