Hybrid composites based on carbon nanotubes and graphene nanosheets outperforming their single-nanofiller counterparts

The electrical properties of epoxy hybrids filled with Graphene Nanosheets (GNs) and Multi-Wall Carbon Nanotubes (MWCNTs) were investigated by Tunneling Atomic Force Microscopy (TUNA) to understand the correlation between electrical conductivity, on a micro/nano space scale, and the arrangement of the electrically conductive paths through the sample. Two different amounts of mixed fillers, namely below 0.1 wt% and above 0.5 wt%, were dispersed by ultrasonication into a tetrafunctional epoxy matrix at five different MWCNTs:GNs mix ratios. At a low amount of nanoparticles, 0.1 wt%, the hybrid nanofiller concentration allows for detecting a very interesting synergy toward an increase in the electrical conductivity of several orders of magnitude, and a lowering of the Electrical Percolation Threshold (EPT). Both the computational and experimental results high-light that, owing to the hybrid MWCNT/GNs network formation, the hybrid nanocomposites outperform their single-nanofiller counterparts.