Enhanced electromagnetic interference shielding behavior of Graphene Nanoplatelet/Ni/Wax nanocomposites

We report on the electromagnetic interference shielding behavior of Graphene Nanoplatelet (GNP)/Ni/Wax nanocomposites fabricated by a molecular-level mixing process. Blended powders of GNP and Ni nanoparticles with an average size of 80 nm were fabricated by this simple process. Strong interfacial bonding and homogeneous attachment between the two components (graphene and nickel) was achieved by applying functional groups on the GNP. Nano-sized powders were also prepared by the ball-milling process to demonstrate the contribution of the process to shielding properties. After mixing two different GNP/Ni powders in paraffin wax, the electromagnetic interference shielding behavior of GNP/Ni was investigated. The GNP/Ni/Wax sample of 0.7 mm thickness prepared by the molecular-level mixing process showed a shielding effectiveness value of 40 dB in the X-band, while GNP/Ni/Wax samples prepared by the ball-milling process showed a value of 20 dB. The enhancement can be achieved by facilitating charge transfer and providing magnetic dipoles which interact with electromagnetic waves. Functional groups on the GNP not only provide nucleation sites for Ni nanoparticles of uniform size but help the GNP/Ni powders to be homogeneously dispersed in wax by enhancing interfacial interactions between GNP/Ni and wax.