Copolymer formation of 4-vinylbenzyl-9H-carbazole-9-carbodithioate and ethylenedioxythiophene and capacitive behavior

Abstract

In this study, first, a new monomer of 4-vinylbenzyl 9 H-carbazole-9-carbodithioate (VBzCzCT) was chemically synthesized and characterized using Fourier transform infrared (FTIR) reflectance, proton nuclear magnetic resonance (1H NMR), and carbon nuclear magnetic resonance (13C NMR) spectroscopies. Second, VBzCzCT and 3,4-ethylenedioxythiophene (EDOT) monomers were electrocopolymerized (VBzCzCT- co-EDOT) in 0.1 M sodium perchlorate (NaClO4)/acetonitrile (CH3CN) on glassy carbon electrode (GCE) using cyclic voltammetry (CV). Third, the best deposition conditions on the electroactivity of the modified homopolymers and copolymer were studied and characterized using different techniques such as CV, FTIR-attenuated total reflectance, scanning electron microscopy–energy dispersion x-ray analysis, and electrochemical impedance spectroscopy (EIS) analysis. The specific capacitance ( Csp) of poly(VBzCzCT) (P(VBzCzCT)) was obtained as 20.5 mF cm−2. However, the Csp of P(VBzCzCT- co-EDOT)/GCE was obtained as 45.5 mF cm−2. There is an important improvement in the capacitance value of copolymer formation. The Csp value increases more than twice from P(VBzCzCT) to copolymer. The highest double layer capacitance ( Cdl = approximately 27.5 mF cm−2) was obtained for P(VBzCzCT- co-EDOT) and P(EDOT) compared with P(VBzCzCT) ( Cdl = approximately 8.28 mF cm−2. Finally, simulation graphs of Nyquist, Bode-magnitude, and Bode-phase plots were given for homopolymers and copolymer for the electrical equivalent circuit model of Rs( Q1( R1( C1( R2( C2( R3· W))))))( C3 R4). The EIS results of P(VBzCzCT), P(EDOT), and P(VBzCzCT- co-EDOT) might be studied as promising active electrode materials for (super)capacitor evaluations.