Enhanced dielectric constant of PVDF-based nanocomposites with one-dimensional core-shell polypyrrole/sepiolite nanofibers

Abstract In this paper, the natural sepiolite nanofibers (Sep) were selected to be as the dispersion supporter of conductive polymer polypyrrole (PPy) owing to low cost, natural nanowires and well dispersibility in the PVDF matrix. The one-dimensional core-shell polypyrrole/sepiolite (PPy@Sep) nanofibers were synthesized by in-situ polymerization and subsequently introduced into the PVDF matrix by the solution blending method. The experimental results demonstrated that PPy was uniformly coated on the Sep surface. The PPy@Sep nanofibers could disperse in PVDF matrix well and produce the effect of heterogeneous nucleation on PVDF crystallization. With the increasing content of PPy@Sep from 1 wt% to 5 wt%, the dielectric constant of PVDF-based nanocomposites improved from 12 to 40 at 100 Hz because of the hierarchical interfacial polarization originating from the PPy/Sep interface and PPy/PVDF interface and microcapacitor effect. Meanwhile, a low dielectric loss was observed in the nanocomposites.