Effect of rGO:MWCNTs ratio on electrical conductivity of polyazomethine/rGO:MWCNTs nanocomposites

Abstract

Using solution blending method, we produced nanocomposites based on polyazomethine (PAZ) loaded with hybrid carbon nanofillers. The nanofillers comprised reduced graphene oxide (rGO) and multi-walled carbon nanotubes (MWCNTs). The total nanofiller loading was equal to 1 wt% while the rGO:MWCNTs ratio varied as follows: 100:0, 75:25, 50:50, 25:75, and 0:100 wt%: wt%. The complex dielectric permittivity data obtained with a broadband dielectric spectrometer were used to analyze electrical conductivity of the nanocomposites in wide ranges of frequency and temperature. Electrical conductivity was found to increase with increasing MWCNTs portion and its maximum value was achieved when the nanofiller contained the MWCNTs nanoparticles exclusively. We extracted the electrical conductivity components, dc conductivity σdc and ac conductivity σac, and analyzed their behavior as function of frequency and temperature. The temperature dependences of σac were described with the Arrhenius equation, whereas its frequency dependences were characterized with a power function. For explaining the σac behavior, the correlated barrier hopping mechanism was accepted. Interfacial interactions between the hybrid nanofillers and the polymer matrix (the Maxwell-Wagner-Sillars effect) were detected. It was found to be strongly pronounced in the nanocomposites with high portion of MWCNTs in the hybrid fillers.