Preparation and selected properties of a composite of the C60‐Pd conducting polymer and single‐wall carbon nanotubes

Abstract

AbstractA thin film of a new composite consisting of the redox conductive fullerene‐palladium polymer (C60‐Pd) and single‐wall carbon nanotubes, non‐covalently functionalized with 1‐pyrenebutiric acid (pyr‐SWCNTs), was electrochemically prepared in the acetonitrile: toluene (1: 4, v: v) solution containing C60, pyr‐SWCNTs, and palladium acetate, Pd(ac)2, under multi‐scan cyclic voltammetry (cv) conditions. A tetra(n‐butyl)ammonium salt, vis. 0.1 M (TBA)ClO4 or (TBA)PF6, was used as the supporting electrolyte. Electrochemical and visco‐elastic properties of the composite film were investigated by simultaneous cv and piezoelectric microgravimetry (pm) measurements. The Raman spectra indicated that pyr‐SWCNTs were incorporated in the film during preparation of the composite by electropolymerization. Mass of the deposited composite film was determined by pm using an electrochemical quartz crystal microbalance (EQCM). The EQCM also allowed us for simultaneous recording, in different potential ranges, the current, resonant frequency changes, and dynamic resistance changes vs. potential, of a quartz crystal resonator with its electrode coated by the composite film. The performed EQCM experiments revealed that both films were electrochemically active at potentials more negative than ca. –0.5 V. However, the presence of pyr‐SWCNTs in the film increased the electrode capacitance, as manifested by the increase of both the cv cathodic and anodic current. Moreover, the presence of pyr‐SWCNTs in the C60‐Pd polymer improved its visco‐elastic properties for the potentials more negative than –0.9 V vs. Ag/AgCl by making the C60‐Pd/pyr‐SWCNTs film more rigid than the pristine C60‐Pd film. From the highest slopes of the rising portions of the cathodic currents in the range ca. –0.4 to –0.6 V the redox conductivity values were determined. This conductivity for the C60‐Pd/pyr‐SWCNTs composite film was higher than that for the genuine C60‐Pd film. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)