Enhanced Dielectric Performance of P(VDF-HFP) Composites with Satellite-Core-Structured FeO@BaTiO Nanofillers.

Polymer dielectric materials are extensively used in electronic devices. To enhance the dielectric constant, ceramic fillers with high dielectric constant have been widely introduced into polymer matrices. However, to obtain high permittivity, a large added amount (>50 vol%) is usually needed. With the aim of improving dielectric properties with low filler content, satellite-core-structured FeO@BaTiO (FeO@BT) nanoparticles were fabricated as fillers for a poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)) matrix. The interfacial polarization effect is increased by FeO nanoparticles, and thus, composite permittivity is enhanced. Besides, the satellite-core structure prevents FeO particles from directly contacting each other, so that the dielectric loss remains relatively low. Typically, with 20 vol% FeO@BT nanoparticle fillers, the permittivity of the composite is 31.7 (1 kHz), nearly 1.8 and 3.0 times that of 20 vol% BT composites and pure polymers, respectively. Nanocomposites also achieve high breakdown strength (>150 KV/mm) and low loss tangent (~0.05). Moreover, the composites exhibited excellent flexibility and maintained good dielectric properties after bending. These results demonstrate that composite films possess broad application prospects in flexible electronics.