Enhancement of dielectric permittivity in carbon nanotube/polyvinylidene fluoride composites by constructing of segregated structure

Abstract

A segregated structure was constructed based on pristine multi-walled carbon nanotubes (MWCNTs) fillers and polyvinylidene fluoride (PVDF) matrix to enhance the dielectric permittivity of the composites. It is found that the MWCNTs could disperse uniformly in the PVDF matrix through grinding method and a low percolation threshold of 2.7 vol% was achieved. The effect of MWCNTs on the dielectric properties of MWCNTs/PVDF composites was investigated at measuring voltage 4 V. A giant dielectric permittivity with the value of 53460 at 100 Hz is achieved in the composites with 6.1 vol% MWCNTs, while the loss tangent is only 134. Furthermore, the dielectric permittivity decreases slowly and a high value of 11815 still can be seen when the measuring frequency was 104 Hz. The main reason for the giant dielectric permittivity can be attributed to the polarization effect coming from the interface between PVDF powder and MWCNTs. The results suggest that the giant dielectric permittivity can be achieved in pristine MWCNTs/PVDF composites with segregated structure. It is promising for bypass capacitor applications.