Typical synergistic effect of graphite nanoplatelets and carbon nanotubes and its influence on polymer-based dielectric composites

Abstract

Graphite nanoplatelets (GNPs) with their intrinsic two-dimensional structure make an excellent compromise of advantages of both graphite and graphene. Due to their outstanding inherent properties, GNPs have been widely used as the functional fillers to improve certain performances of polymer-based composites. However, the multi-layer stacked construction of GNPs could form aggregations easily, which limits their application in polymer-based dielectric composites. Here, the authors exhibit a polydimethylsilicone (PDMS)-based nanocomposite which loading equivalent carbon nanotubes (CNTs) and GNPs as co-loading fillers, whose dielectric properties are improved significantly. The composites were fabricated through a highly-shearing mechanical mixing process. During the mixing process, both intrinsic CNTs entanglements and GNPs stacked aggregation could be ameliorated due to the interaction between these two types of fillers. Compared with the GNPs solely loaded composites, a small quantity of CNTs addition endows GNPs/CNTs/PDMS ternary composites with a significantly decreased percolation threshold (fc ∼ 1.7 vol.%). Both GNPs and CNTs, these two representative conductive carbon constructions with high aspect ratios are able to effectively enhance the establishing efficiency of internal conductive network inner composites. These results indicate that the development of internal conductive network and dielectric performance of nanocomposites are able to be optimised through the strategy of taking advantage of the synergistic effect of multi-type fillers reasonably.