High dielectric permittivity and low percolation threshold in polymer composites based on SiC-carbon nanotubes micro/nano hybrid

Vertically aligned carbon nanotubes (CNTs) were synthesized on SiC microplates. Resultant SiC-CNTs hybrids were further incorporated into poly(vinylidene fluoride) (PVDF) as conductive filler to prepare percolative composites. They exhibited a much low percolation threshold (1.47 vol %), but the dielectric permittivity was enhanced significantly. The largest dielectric permittivity of 8700 was observed in the SiC-CNTs/PVDF composites with 2.3 vol % CNTs at 100 Hz. A microcapacitor model was proposed to explain the obtained results based on the special geometry of the hybrid SiC-CNTs filler.