389753 Conductive Titanium Dioxide/Polyaniline Nanocomposites with Negative Giant Magnetoresistance

Tuesday, November 18, 2014: 3:40 PM
210 (Hilton Atlanta)
Jiang Guo1, Hongbo Gu1, Huige Wei1, Yiran Wang1, Suying Wei2 and Zhanhu Guo1, (1)Integrated Composites Laboratory (ICL), Dan F. Smith Department of Chemical Engineering, Lamar University, Beaumont, TX, (2)Department of Chemistry and Biochemistry, Lamar University, Beaumont, TX

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

(1)        Gu, H.; Guo, J.; Wei, H.; Huang, Y.; Zhao, C.; Li, Y.; Wu, Q.; Haldolaarachchige, N.; Young, D. P.; Wei, S.; Guo, Z.: Giant magnetoresistance in non-magnetic phosphoric acid doped polyaniline silicon nanocomposites with higher magnetic field sensing sensitivity. Physical Chemistry Chemical Physics 2013, 15, 10866-10875.

(2)        Guo, J.; Gu, H.; Wei, H.; Zhang, Q.; Haldolaarachchige, N.; Li, Y.; Young, D. P.; Wei, S.; Guo, Z.: Magnetite–Polypyrrole Metacomposites: Dielectric Properties and Magnetoresistance Behavior. The Journal of Physical Chemistry C 2013, 117, 10191-10202.


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