Electrical conductivity and dielectric properties of PMMA/graphite nanoplatelet ensembles

Poly(methyl methacrylate) (PMMA)/graphite nanoplatelet (GNP) ensembles were prepared by in situ   polymerization of MMA in the presence of GNPs with the aid of sonication and heating. Electrical conductivity and dielectric properties of the ensembles were measured using the four-point probe resistivity measurement method and a Network Analyzer. The results showed that the electrical behavior of PMMA/GNP ensembles can be described well by percolation theory. The electrical conductivity of the ensemble was found to exhibit an insulator–conductor transition at a very low percolation threshold for GNPs. The percolation threshold of PMMA/GNP at room temperature was only about 1wt% filler content, much lower than that of the ensembles filled with conventional graphite particles. Results showed that the difference in filler geometry (high aspect ratio and surface area) has a very significant effect on forming a conducting network in the PMMA matrix and improves both electrical and dielectric properties.

► Conductive PMMA/GNP ensembles were prepared by in situ polymerization.
► An electrical conductivity of 10−4 S/cm and dielectric loss factor of 10−6 were obtained for the ensemble with 5 wt% GNP.
► Electrical behavior of ensembles can be described well by the percolation theory.
► Both conductivity and dielectric loss factor were greatly enhanced near the percolation threshold.