Enhanced dielectric properties in polyvinyl alcohol - Multiwall carbon nanotube composites

Here we report the study of direct current (DC) and alternate current (AC) electrical transport properties and current voltage (I-V) characteristic of Polyvinyl Alcohol - Multiwall Carbon nanotube (PVA -MWCNT) composites, prepared by an in-situ chemical oxidative preparation technique, within temperature range 300 K <= T <= 423 K and in the frequency range 150 Hz <= f <= 2 MHz. The DC conductivity gives the presence of two different activation energies at two different temperature regions. It is observed that the dielectric constant of composite film is higher in comparison to pure PVA film and is well-fitted with modified Cole-Cole equation. The presence of hydroxyl group affects the relaxation phenomenon of composite film. The frequency variation of AC conductivity follows the power law (f(s)) and is found to follow correlated barrier hopping (CBH) model. The imaginary part of electric modulus shows non-Debye type asymmetric behaviour. The current - voltage characteristic has been analysed by the concept of back to back Schottky diode. (C) 2015 Elsevier B.V. All rights reserved.