Preparation of MWCNTs/PVDF composites with high-content β form crystalline of PVDF and enhanced dielectric constant by electrospinning-hot pressing method

In this work, the multi-walled carbon nanotubes (MWCNTs)/poly(vinylidene fluoride) (PVDF) composites were prepared by the electrospinning-hot pressing method. The MWCNTs distributed well in the PVDF matrix, which was confirmed by the investigation of scanning electron microscope. According to the results of the Fourier transform infrared and the wide-angle X-ray diffraction, a large amount of the useful polar β crystalline phase of PVDF was formed in the MWCNTs/PVDF composites due to the synergic effect of the electrospinning and the MWCNTs. Moreover, the good dielectric performance of the MWCNTs/PVDF composites could be not only obtained from the electrospinning-hot pressing method but also controlled by the layer amount of the electrospun wrap-wrap laminated MWCNTs/PVDF composite membrane in the hot pressing step. When the MWCNTs was 5 wt%, the dielectric constant of the three-layer MWCNTs/PVDF composite reached as high as 74.6 at 1000 Hz with the dielectric loss factor of only 0.124.