Achieving ultrahigh synergistic effect in enhancing conductive properties of polymer composites through constructing the hybrid network of ‘rigid’ submicron vapor grown carbon fibers and ‘reelable’ carbon nanotubes

Enhancing the synergistic efficiency of different fillers in the composites is very significant from viewpoints of reducing fabricating cost and acquiring promising comprehensive properties. Inspired by the stem parasitic plant cuscuta austrails (dodder), the highly efficient conductive network in the composites was constructed through the ‘rigid’ submicron vapor grown carbon fibers (s-VGCFs) and ‘reelable’ carbon nanotubes (CNTs), in which the homogeneously dispersed s-VGCFs acted as the framework while CNTs bridged adjacent s-VGCFs and also partly entangled on s-VGCFs. Compared with the binary composites containing only s-VGCFs (or CNTs), the presence of very small quantity of CNTs (or s-VGCFs) led to the significant reduction of percolation thresholds from 3.082 wt% to 0.876 wt% (or from 0.258 wt% to 0.024 wt%), and the extremely high synergistic efficiency of 1.5 × 107 was achieved. Specifically, the impact of different compounding sequences on the hybrid network structure of fillers was also discussed. This work provides a new strategy to construct the hybrid network structure of fillers with extremely high synergistic effect and it might be applied in fabrication of the conductive composites with excellent mechanical properties.