Electrical percolation behaviour of hybrid nanocarbon-polycarbonate composites

A study of the electrical percolation behaviour of conductive polymer composites containing blends of carbon black (CB), carbon nanotubes (CNT), and graphene nanoplatelets (GNP) is presented. Transmission electron microscopy (TEM) and conductive atomic force microscopy (CAFM) were used to reveal the morphology and connectivity of nanofiller networks and measurements of bulk conductivity carried out to probe percolation behaviours. We find that the percolation threshold and percolation exponent can be controlled by informed selection of fillers with the controlling parameter for the percolation threshold being the average particle aspect ratio, and that for the percolation exponent being the contact resistance between particles. Experimental observations are supported by Monte-Carlo simulations of particles with well-defined geometries.