Synthesis of 6-(3,6-di(thiophene-2-yl)-9H-carbazole-9-yl)-hexanoic acid, alternating copolymer formation, characterization and impedance evaluations

Abstract

In this paper, 6-(3,6-di(thiophene-2-yl)-9H-carbazole-9-yl)-hexanoic acid (ThCzHa) comonomer was newly synthesized and characterized with Fourier transform infrared spectroscopy (FTIR) and 1H-NMR. The synthesized comonomer was electrochemically deposited onto carbon fiber microelectrode (CFME). An electrochemical impedance study on the prepared electrodes is reported. Poly(ThCzHa)/CFME is characterized by cyclic voltammetry (CV), Fourier transform infrared reflectance-attenuated total reflection spectroscopy (FTIR-ATR), scanning electron microscopy–energy dispersive X-ray analysis (SEM–EDX), and electrochemical impedance spectroscopy. Capacitive behaviors of modified CFMEs were defined via Nyquist, Bode-magnitude, Bode-phase, and Admittance plots. The equivalent circuit model of R(Q(R(C(R(C(RW))))))(CR) was examined for polymer/electrolyte system. The effect of initial monomer concentration (0.5, 1.0 and 1.5 mM) on the formation of alternating copolymer is reported in 0.1 M sodium perchlorate/acetonitrile solution. The copolymer structure was also characterized by FTIR-ATR, SEM–EDX, and CV measurements. The highest low frequency capacitance (C LF = 5.2 mF cm−2), double layer capacitance (C dl=100 F cm−2) and maximum phase angle ∼82o at the frequency of 0.1 Hz were obtained for [ThCzHa]0 = 0.5 mM.