Enhanced Electrical Conductivity in Polystyrene Nanocomposites at Ultra-Low Graphene Content

We compared the electrical conductivity of multiwalled-carbon-nanotube/polystyrene and graphene/polystyrene composites. The conductivity of polystyrene increases from similar to 6.7 x 10(-14) to similar to 3.49 S/m, with an increase in graphene content from similar to 0.11 to similar to 1.1 vol %. This is similar to 2-4 orders of magnitude higher than for multiwalled-carbon-nanotube/polystyrene composites. Furthermore, we show that the conductivity of the graphene/polystyrene system can be significantly enhanced by incorporation of polylactic acid. The volume-exclusion principle forces graphene into the polystyrene-rich regions (selective localization) and generates similar to 4.5-fold decrease in its percolation threshold from similar to 0.33 to similar to 0.075 vol %.