Polyimide‐carbon nanotubes nanocomposites: electrical conduction behavior under cryogenic condition

Abstract

This study is aimed to investigate the electrical conduction behavior of polyimide (PI)/multiwall carbon nanotubes (CNTs) nanocomposites in cryogenic environment (temperature from 10 to 300 K) prepared by in situ polymerization technique. The experimental results of direct current (DC) electrical conductivity have been fitted with different theoretical models to check their applicability and to understand the conduction behavior for the present nanocomposite system. The PI/CNT nanocomposites show low electrical percolation threshold. Negative temperature coefficient effect of resistivity is observed for all the composites under investigation. The analysis shows that Mott's variable range hopping (VRH) model is more applicable compared to Arrhenius and Kivelson models for the present composites over the entire range of measurement temperature. The electronic transport behavior in each composite at temperature above 70 K can be ascribed to thermally activated tunneling of charge carriers through insulating barriers between CNTs; however, the electronic transport behavior at temperature below 70 K can be attributed to three dimensional VRH of charge carriers through the networks of CNTs in the polymer composite. The current–voltage characteristics of the composite show non‐ohmic behavior for temperature below 60 K and become ohmic in nature as temperature rises to 300 K. POLYM. ENG. SCI., 57:291–298, 2017. © 2016 Society of Plastics Engineers