Enhanced electrical properties of polyaniline carbon nanotube composites: Analysis of temperature dependence of electrical conductivity using variable range hopping and fluctuation induced tunneling models

Abstract

Hydrochloric acid doped polyaniline – multiwalled carbon nanotube nanocomposites are successfully synthesized by chemical in-situ polymerization and their structural, thermal, morphological and electrical properties are investigated. The synthesized PANI-MWNT composites show quite high room temperature DC electrical conductivity, very good thermal stability and a weak temperature dependence of conductivity comparable to doped polymers showing metallic conductivity. The charge transport mechanism in these nanocomposites is analyzed using variable range hopping and fluctuation induced tunneling models, and validation of these models is also carried out using the statistical methods, regression analysis and the analysis of variance. The temperature variation of electrical conductivity is found to best fit with the three-dimensional variable range hopping model. The one-dimensional nature of MWNT enhanced the charge transport in the composite materials. The present study is significant in polymer/organic materials with high mobility charge carriers for various electrical applications such as EMI shielding. The stable DC electrical conductivity observed in the PANI-MWNT composites even at high temperatures highlights the prospects of application of these composites in the fabrication of devices capable of operating at high temperatures. The multifunctional characteristics of MWNT make these composites a potential candidate for the electrical, thermal, sensing and actuating applications.