A novel all-organic DIPAB/PVDF composite film with high dielectric permittivity

A novel all-organic composite comprising polyvinylidene fluoride (PVDF) and diisopropylammonium bromide (DIPAB) crystal particles (0-20 mass%) with significant dielectric properties has been synthesized via coating method. The DIPAB crystal nano-particles were prepared in the PVDF matrix by in situ growth method, which were found effective in transforming structure and enhancing the dielectric properties of the composites. X-ray diffraction pattern and Fourier transform infrared spectroscopy confirmed that the DIPAB in situ particles can improve the content of the electroactive beta phase nucleation in PVDF matrix, whereas the PVDF matrix could induce the (001) preferred orientation of the DIPAB nano-crystal. And the dielectric performance of the DIPAB/PVDF composite was significant influenced by the enhanced electroactive beta phase and (00l) textured DIPAB. Relative dielectric constants as high as 94 was obtained at 40 Hz with 5 mass% DIPAB filler, which is 11-fold higher than that of the pure PVDF matrix (similar to 8.5). The breakdown strength decreased as the mass fraction of DIPAB increased but still stayed more than 38.9 kV/mm.