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 β phase nucleation in PVDF matrix, whereas the PVDF matrix could induce the (00l) preferred orientation of the DIPAB nano-crystal. And the dielectric performance of the DIPAB/PVDF composite was significant influenced by the enhanced electroactive β 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 (~8.5). The breakdown strength decreased as the mass fraction of DIPAB increased but still stayed more than 38.9 kV/mm.