Characterization of Nanocomposite Based on Carbon Nanotubes and Conducting Polymers with Different Dopants for Obtaining of Modified Electrodes

Abstract

Nanocomposite films of functionalized single-walled carbon nanotubes (SWCNTs), 3,4-ethylene dioxythiophene (PEDOT) and different dopants (sodium dodecyl sulphate-SDS, tiron, 3-methylthiophene) were grown electrochemically from aqueous solutions such that constituents were deposited simultaneously onto substrate electrodes. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR) revealed that the composite films consisted of nanoporous networks of SWCNTs coated with polymeric film. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) demonstrated that these composite films had similar electrochemical response rates to pure polymeric films but a lower resistance and much improved mechanical integrity. The negatively charged carbon nanotubes (CNTs) served as anionic dopant during the electropolymerization to synthesize polymer/CNTs composite films. The specific electrochemical capacitance of the composite films is a significantly greater value than that for pure polymer films prepared similarly. The higher capacitance of the composite films results obviously from the contribution of the embedded SWCNTs that provide interconnected pathways for electrons through the SWCNTs and ions through the pore network or the direct interaction between the delocalised electrons on polymer chains and the SWCNTs.Using these composite films, the modified electrodes with improved properties were obtained.