(393b) Conductive Titanium Dioxide/Polyaniline Nanocomposites with Negative Giant Magnetoresistance

The conductive polyaniline (PANI) polymer nanocomposites reinforced with titanium dioxide (TiO₂) nanoparticle have been successfully fabricated using a facile surface initiated polymerization (SIP) method. The scanning electron microscope (SEM) is used to characterize the surface morphology of the as-received TiO₂ nanoparticles nanoparticles, pure PANI and TiO₂/PANI nanocomposites. The high resolution transmission electron microscope (HRTEM) is used to observe the nanoparticle dispersion within the polymer matrix. The Fourier transform infrared (FT-IR) spectroscopy is used to study the chemical structure of the TiO₂/PANI nanocomposites. The thermal stability of the TiO₂/PANI nanocomposites is studied by thermogravimetric analysis (TGA). Both pure PANI and TiO₂/PANI nanocomposites show a positive permittivity within the measured frequency range at room temperature. Adding the TiO₂ nanoparticles into the PANI matrix has little effect on the optical band gap of TiO₂/PANI nanocomposites compared with that of pure PANI. Temperature dependent resistivity results indicate a semiconductor behavior and a quasi 3-dimensional variable range hopping (VRH) electrical conduction mechanism for the synthesized samples.¹ The negative magnetoresistance (MR) is observed in the synthesized TiO₂/PANI nanoparticles at 290K and 130K, and analyzed by the orbital magnetoconductivity theory (forward interference model).²

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