Enhanced dielectric and capacitive performance in polypropylene/poly(vinylidene fluoride) binary blends compatibilized with polydopamine

Polymer blending strategy has demonstrated to be efficient in enhancing the capacitive performance of dielectric polymers represented by poly(vinylidene fluoride) (PVDF). Special attention is paid to the polymeric reinforcements which are miscible with PVDF. Immiscible polymeric reinforcements for PVDF based blends are rarely reported because of the interfacial compatibility issue. In this work, we aimed to explore the possibility of immiscible component polypropylene (PP) in modulating the capacitive performance of PVDF. A two-step fabrication process and polydopamine compatibilizer were developed to improve the interfacial compatibility between two components. The resultant binary blend demonstrated to perform suppressed dielectric loss, improved polarization level and consequently enhanced capacitive performance. With an optimized addition of 10 wt% PP, a maximum discharge energy density of 12.1 J/cm3 and discharge efficiency of 69.3% can be obtained in blends under 350 MV/m, while those of pure PVDF were 5.7 J/cm3 and 45.6%, respectively.