Synthesis and characterization of processible conducting polyaniline/V2O5 nanocomposites

Flexible, conducting polyaniline/V2O5 nanocomposite films (PAPSA)(x)V2O5 were prepared by simply mixing water soluble polyaniline, poly(aniline-co-N-(4-sulfophenyl)aniline) (PAPSA), with V2O5 at room temperature. Two types of (PAPSA)(x)V2O5 films with different solubility were isolated. XRD data showed that the interlayer spacing of the water-soluble (PAPSA)(x)V2O5 film, in which the polymer chains occupied the vacancies of V2O5 xerogel, is ca. 11.5 +/- 0.5 Angstrom. The d-spacing of the water insoluble (PAPSA)(x)V2O5 film (small amount, <5%) is 13.5 +/- 0.5 Angstrom, which is consistent with the insertion of polyaniline chains into the V2O5 interlayer space. In both phases, PAPSA and V2O5 were homogeneously mixed as revealed with SEM, depth profile SIMS and Auger analyses. The room-temperature conductivity of the water-soluble (PAPSA)(x)V2O5 film was in between those of a PAPSA pellet and a V2O5 xerogel and the conductivity increased with temperature, characteristic of thermally activated behavior. Cyclic voltammograms of the nanocomposite films showed two pairs of red-ox peaks with good reversibility. The color of the films can be yellowish green, green, brown, orange or purple, depending on the applied potential and the stoichiometry of the composites. (PAPSA)(x)V2O5 has much better electrochemical stability relative to PAPSA and its mechanical properties are superior to that of V2O5 xerogel.