(289h) Polyaniline – Metal Oxides Nanocomposites with Unique Physicochemical Properties

The unique physicochemical properties of polyaniline (PANI)/metal oxides polymer nanocomposites (PNCs) were systematically studied with the PNCs containing different kinds of metal oxides. PANI PNCs with non magnetic nanoparticles (NPs)-barium titanate (BaTiO₃) and magnetic NPs-manganese ferrite (MnFe₂O₄) were synthesized by a surface initiated polymerization method. Giant magnetoresistance (GMR) was observed in the PNCs, and the value was found to depending on the species and the loading of NPs. With the magnetic field of 9E5 Oe, the GMR can reach to -34% for PNCs with 30.0 wt% MnFe₂O₄ NPs and 30% for PNCs with 1.0 wt% BaTiO₃ NPs. And the positive and negative GMR was analyzed theoretically from the wave functional shrinkage model and forward interference model, respectively. Compared with the negative real permittivity of PNCs with BaTiO₃ NPs, all the PNCs with MnFe₂O₄ NPs showed high positive dielectric permittivity and high dielectric loss value, which is due to the interfacial polarization. The electron transportation behavior of the PNCs was studied and for both PNCs, the temperature dependent resistivity result reveals a 3-d variable range hopping (VRH) electron transport mechanism. By varying the loading level of NPs, the crystalline structure, thermal stability and morphology of the PNCs were also systematically studied. And the peak shift observed in the FT-IR spectra of both PNCs indicated a strong interaction between the formed PANI and the metal oxides NPs.