Electrochromic and conductivity properties:: a comparative study between melanin-like/V2O5•nH2O and polyaniline/V2O5•nH2O hybrid materials

In this work, we report the synthesis and some properties of melanin-like/2VO5 . nH(2)O and polyaniline/V2O5 . nH(2)O hybrid materials that have potential applications in optics and electronics. The hybrid materials were obtained by an oxidative polymerization/intercalation process reacting the gel with the monomers of the polymers. The optical properties of the compounds in film forms were measured using ultraviolet-visible (UV-Vis) spectroscopy. Thermogravimetric analysis, differential gravimetric analysis and de conductivity techniques were also used to study the compounds. The X-ray diffractograms indicate that the lamellar structure of the V2O5 is preserved with the increase of the inter-planar space from 1.18 +/- 0.05 to 1.40 +/- 0.05 nm. The presence of the organic phase induced the reduction of V(V) ions to V(IV) and increased the de conductivity and affected the spectroelectrochemical properties of the samples. (C) 2000 Elsevier Science B.V. All rights reserved.