Improving the dielectric performance of poly(vinylidene fluoride)/polyaniline nanorod composites by stretch-induced crystal transition

The introduction of conductive polyaniline (PANI) can significantly improve the dielectric constant of polymer-based materials. However, there is a drawback of high dielectric loss. Herein, a simple and efficient stretching process was applied to improve the dielectric performance of poly(vinylidene fluoride)/PANI (PVDF/PANI) nanorod films through the stretch-induced crystal transition from non-polar -crystal to polar -crystal in PVDF and the oriented distribution of PANI nanorods. XRD, DSC and Fourier transform IR analyses indicate that the stretched PVDF and stretched PVDF/PANI films possess a high content of -crystal at the stretching temperature of 135 degrees C under a stretching ratio of 200%-400%. Furthermore, the stretched PVDF/PANI film with 10wt% PANI displays a high dielectric constant of 338 at 100Hz, which is increased by 20% compared to non-stretched PVDF/PANI film (281). More importantly, the corresponding dielectric loss is reduced from 0.31 for the non-stretched film to 0.17 for the stretched film. (c) 2018 Society of Chemical Industry