Electrochemical impedance spectroscopic study of electrocoated polythiophene and poly(2-methyl thiophene) on carbon fiber microelectrode for microcapacitor

Abstract

In this study, N-thiophene (T), and N-2 methylthiophene (MT) homopolymers were electrocoated on carbon fiber microelectrodes (diameter ~7 ?m) by cyclic voltammetry within a potential range from 0.0 to 2.0 V with well - defined parameters. All the initial monomer concentrations (from 0.1 M to 1 M) were electrodeposited in 0.1 M sodium perchlorate (NaClO4) / acetonitrile (ACN) solution and characterized by cyclic voltammetry (CV), ex-situ FTIR attenuated total reflectance spectroscopy (FTIR - ATR), and scanning electron microscopy (SEM). The electrochemical impedance spectroscopic measurements of polythiophene (PT) and poly (2-methyl thiophene) (PMT) were given comparatively. The existence of a capacitance behavior is shown by Nyquist, Bode magnitude, Bodephase, Admittance plots relationship. The T-deposited electrode in the initial monomer concentration of 0.5 M exhibits high specific capacitance of 1.13 F g-1, in comparison with a value of 6.35 mF g-1 for MT modified electrode in the initial monomer concentration of 0.2 M. © 2009 by ESG.