Circuit Model Evaluation of Poly(methyl pyrrole-co-2-(9H-carbazole-9-yl)ethyl methacrylate) on Carbon Fiber

Abstract

Methyl pyrrole (N-MPy) and 2-(9H-carbazole-9-yl) ethyl methacrylate (CzEMA) monomers were electrocopolymerized on carbon fiber microelectrode (CFME) as an active electrode material. The electropolymerization of monomers was studied in 0.1 M sodium perchlorate (NaClO4)/acetonitrile (ACN) solution. The detailed characterization of the resulting electrocoated poly(N-MPy-co-CzEMA)/CFME thin films was studied by various techniques, i.e., cyclic voltammetry (CV), Scanning electron microscopy – Energy Dispersive X-ray analysis (SEM-EDX), and Electrochemical impedance spectroscopy (EIS). The effects of monomer mole fractions (mole fraction, XCzEMA = nCzEMA/nMPy + nCzEMA) (0.5, 0.66, 0.75, 0.83 and 0.91) during the preparation of modified electrodes were examined by EIS. Capacitive behaviors of modified CFMEs were defined via Nyquist, Bode-magnitude, Bode-phase and Capacitance plots. Circuit model of R(Q(R(C(R(C(RW))))))(CR) was suggested to fit the theoretical and experimental values. The lowest low frequency capacitance value and total charge (Q = 112.9 mC) during electrodeposition of polymer thin film by CV method in the mole fraction of XCzEMA = 0.75 (CLF = ∼27.2 mF cm−2). However, the highest double layer capacitance of polymer/electrolyte system (C1 = 25.4 mF cm−2; C2 = 159.1 mF cm−2; C3 = 4.54 mF cm−2) was obtained in the same mole fraction.