Polyamide 11/poly(vinylidene fluoride) blends as novel flexible materials for capacitors

A novel capacitor with high dielectric constant (F) has been developed by blending poly(vinylidene fluoride) (PVDF) with polyamide (PA11). The blends show high dielectric constants (epsilon(blend) = 40), which give better frequency stability (1 MHz), and excellent mechanical properties. Based on certain volume fractions, the measured dielectric constants (epsilon(blend)) were found to exceed those of the corresponding polymers, in contrasted to conventional composites, where epsilon(polymerA) < epsilon(composite) < epsilon(polymerB). SEM investigations suggest that the enhanced dielectric behavior originates from significant interfacial polymer-polymer interactions. DSC and XRD demonstrate that blending PA11 with PVDF affects the crystalline behavior of each component. However, the PA11/PVDF blends exhibit a slightly high dielectric loss (tan delta approximate to 0.17), which is a great disadvantage to a capacitor. Adding a copolymer of styrene and maleic anhydride so decreased the dielectric loss (tan delta approximate to 0.057)) and increased the dielectric constant (epsilon(bled) = 60). Our findings suggest that the high-e polymeric blends created represent a novel type of material 30 that is flexible and easy to process, of relatively high dielectric constant, of high breakdown 20 strength and, moreover is suited to applications in flexible electronics.