An electrochemical study of soluble copolymer of ethyl carbazole with N-methyl pyrrole and 3-methyl thiophene

Copolymers of N-ethyl Carbazole (ECZ) with N-Methyl Pyrrole (N-MPy) and 3-Methyl Thiophene (3-MTh) were synthesized on platinum substrate and electrochemical investigation of polymeric films was performed. The characterization of homopolymer and copolymer films was performed by electrochemical methods (i.e. polarization curves and cyclovoltammetric measurements), solid-state conductivity measurements and spectrophotometric methods comparatively. A possible scheme for the copolymerization has been suggested. Solid state conductivity of PECz can be improved by inclusion of 3MTh and NMPy into chain. The ionization potentials, I_p, electron affinity, E_a, optical band gap, E_g, peak potentials, E_p, and doping degrees, y, of copolymer electrodes were calculated from these measurements. Copolymer electrodes have lower I_p, E _g, E_p values and better switching properties in accordance with homopolymer electrodes. Presence of alkyl group gives solubility to copolymers obtained both chemically and electrochemically.