Synthesis, Structure And Properties Of V₂O₅ Nanocomposite Films Modified With Polypyrrole

The synthesis, structure, properties and interface behavior of nanocomposite materials based on layered V2O5 and MoO3, which can be topotactically reacted with alkali-metal ions ( Li+, Na+, etc. ) have attracted more attention in recent years. The intercalation of polymer into the interlayer is expected to improve the interface and interlayer structure of these materials, resulting in desirable novel characteristics. In this dissertation, vanadium pentoxide sols were synthesized by melt quenching and polypyrrole were prepared by surface chemical oxidation of pyrrole, (PPY)xV2O5 (x=0,0.3,0.5,1,1.5) nanocomposite films were prepared by dispersion direct intercalation of PPY via sol-gel route. Meantime, the structure and properties of the films were investigated.The results of IR and DSC show that the method of surface chemical oxidation can synthesize polypyrrole.The results of XRD, DTA-TG show that the (001) crystal plane distance of (PPY)xV2O5(x=0,0.3,0.5,l,1.5) nanocomposite films increases from 1.2176nm at x=0 to 1.6548nm at x=1.5; and in 200~250 C unshown the glass transformation.The IR analysis indicate that all vibrational modes change remarkably after PPY was intercalated into V205 xerogel interlayer, due to the strong interaction between polymer and inorganic framework. The stretching vibration of V=O shifts to lower wavenumbers, which is contributed to the V=0--H bonding interaction.The N2 adsorption isotherms of the (PPY)xV2O5(x=0,0.3,0.5,l,1.5) show that the nanocomposite films are Langmuir II category and increase the pore size after intercalated PPY.The (PPY)xV2O5(r=0,0.3,0.5,l,1.5) nanocomposite films are mixed conductors and electronic conductivity is nearly equal to total conductivity.The fluorescence spectra shows the (PPY)xV2O5(x=0,0.3,0.5,l,1.5) nanocomposite films have a wide emission band. The intercalation of PPYeffectively shields the electrostatic interaction between Li+ ions and V2O5 layers, and improves the electrochromic behavior of the films. Moreover, the intercalation of PPY leads to the formation of oxygen vacancies in the nanocomposite films.This work was supported by the National Natural Science Foundation of China (Grant No. 59802009 and No. 50172036) and the Natural Science Foundation of Hubei Province.