Synthesis, electrical and magnetotransport properties of polypyrrole-MWCNT nanocomposite

The present work describes the preparation of nanocomposites in which the multiwall carbon nanotubes (MWCNT) have been mixed with conducting polypyrrole (PPy) via an in situ chemical oxidative preparation method. To reveal their structural, morphological and thermal properties, the composites have been characterized by X-ray diffraction, field emission scanning electron microscope, Fourier transform infrared, and thermogravimetric analyses respectively. Electrical transport and magnetotransport properties have been investigated in the temperature range 77-300 K in the presence as well as the absence of a magnetic field up to 1 T. The conductivities of the composites are greater than that of pure polypyrrole. All the investigated samples follow Mott's variable range hopping (VRH) theory whereas the magnetic field dependent conductivity has been explained in terms of two opposite but simultaneously acting hopping effect-wave function shrinkage and forward interference effects. (C) 2011 Elsevier Ltd. All rights reserved.