Structural and magnetic properties of nanocomposites based on nanostructured polyaniline and titania nanotubes

摘要

Nanocomposites consisting of self-assembled polyaniline (PANI) nanostructures and titania nanotubes (TiO_2-NT) were synthesized by the oxidative polymerization of aniline with ammonium peroxydisulfate in an aqueous dispersion of TiO_2-NT (outer diameter ~10 nm), without added acid. The influence of initial mole ratio of aniline to TiO_2 (80, 20, and 5) on the morphology, electrical conductivity, molecular structure, crystallinity, and magnetic properties of synthesized PANI/TiO_2 nanocomposites was studied. Transmission electron microscopy, Raman spectroscopy, and X-ray powder diffraction proved that the shape and structure of TiO_2-NT in the final nanocomposites were preserved. The shape of PANI nanostructures formed in the nanocomposites was influenced by the initial aniline/TiO_2-NT mole ratio. Nanotubes and nanorods are predominant PANI nanostructures in the nanocomposite prepared with the highest aniline/TiO_2 mol ratio of 80. The decrease of aniline/TiO_2 molar ratio induced more pronounced formation of nanorod network. The electrical conductivity of PANI/TiO_2 nanocomposites was in the range (1.3-2.4) × 10~(-3) S cm~(-1). The nanocomposites exhibit weak ferromagnetic behavior. Approximately order of magnitude lower values of coercive field and remanent magnetization were obtained for nanocomposite samples in comparison to pure PANI.