Thermal, electrical, and dielectric properties of reduced graphene oxide-polyaniline nanotubes hybrid nanocomposites synthesized by in situ reduction and varying graphene oxide concentration

In this study, reduced graphene oxide (RGO) has been introduced as conductive filler within polyaniline (PAni) nanotubes (PAniNTs) by in situ chemical reduction method to enhance the properties of PAniNTs. The effect of varied concentration of in situ reduced GO on the structural, thermal, electrical, and dielectric properties of RGO-PAniNTs nanocomposites have been investigated by high resolution transmission electron microscope, X-ray diffraction, Fourier transform infrared, thermogravimetric analysis, I-V characteristics, and impedance analyzer. The enhanced thermal stability of the nanocomposites has been analyzed from the derivative thermogravimetric curves in terms of onset and rapid decomposition temperature. The transport mechanisms have been studied by fitting the nonlinear I-V characteristics to the Kaiser model. The dielectric relaxation phenomena have been investigated by permittivity and modulus formalisms. Characteristic relaxation frequency of RGO-PAniNTs nanocomposites shifts toward higher frequency with increasing RGO concentration indicating a distribution in conductivity relaxation. The distribution of relaxation time has been studied by fitting the imaginary modulus spectra of the nanocomposites to Bergman modified KWW function. The ac conductivity spectra are fitted to the Jonscher's power law equation and enhanced conductivity value of 1.26 x 10(-3) Scm(-1) is obtained for 40 wt % of RGO compared to 1.22 x 10(-4) Scm(-1) for PAniNTs. (c) 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45883.