Improvement of the conductivity, electroactivity, and redoxability of polythiophene by electropolymerization of thiophene in the presence of catalytic amount of 1-(2-pyrrolyl)-2-(2-thienyl) ethylene (PTE)

The electropolymerization of thiophene in the presence of 1-(2-pyrrolyl)-2-(2-thienyl) ethylene (PTE) was investigated. PTE was synthesized via Wittig reaction and by the addition of catalytic amount of PTE during the electropolymerization of thiophene, the conditions of electropolymerization of thiophene were modified. The cyclic votammograms of polythiophenes (PThs) in different conditions were obtained. The analysis of cyclic votammograms of PThs shows a considerable increase in the electroactivity and redoxability when the electropolymerization of thiophene in the presence of catalytic amount of PTE was performed. The presence of PTE during electropolymerization of thiophene leads to an increase in the rate of polymerization too. The cyclic voltammetry (CV) measurement of electron transfer ferro/ferricyanide redox system on different modified glassy carbon (GC) electrode has shown that the rate of charge transfer for PTh in the presence of PTE increased in comparison to pure PTh. The conductivity of obtained polymers was determined by electrochemical impedance spectroscopy (EIS) technique in 3.5% (w/v) NaCl solutions. The Zview(II) software was applied to the EIS to estimate the parameters of the proposed equivalent circuit, based on a physical model for the electrochemical behavior of coatings on GC. The R, value obtained for PTh is 7667 Omega cm(2). This value decreases in the presence of PTE to 4437 Omega cm(2). Thus, the new film has more conductivity. (c) 2008 Wiley Periodicals, Inc.