Temperature dependent charge transport in polymer-carbon nanotube and polymer-reduced graphene oxide composites: A comparison

In this study we compared the charge transport phenomena in various polymer-multi-walled nanotubes (MWNT) and polymer-reduced graphene oxide (RGO) composites. Polystyrene (PS) and poly(methyl methacrylate) (PMMA) have been selected as the insulating polymer matrix. The temperature dependent electrical conductivity data [Park et al, Appl. Phys. Lett. 104, 113101 (2014), Asha et al, AIP Conf. Proc. 1942, 110045 (2018), Bhatia et al, Appl. Phys. Lett. 96, 242113, (2010)] are analyzed using reduced activation energy plots {W=d(lnσ)/d(lnT)} to pin point the transport mechanism. Such a comparative investigation is particularly interesting since distinctly different transport processes are present in these systems and also it helps us to optimize the charge transport properties of these composite systems. The data indicates two important electrical conductivity regimes in these polymer composite systems; insulating regime and metal to insulator transition (MI transition) regime.