Enhanced dielectric permittivity and breakdown strength of poly(vinylidene fluoride) nanocomposites containing core-shell BaTiO3@TiO2 nanofibers

Dielectric capacitor has been rapidly developed in recent years, and the ceramics nanofibers/polymer nanocomposites with improved dielectric properties have huge potential in exploitation and application. In this article, the barium titanate (BT) nanofibers were synthesized by electrospinning and encapsulated by titanium dioxide (TiO2) via sol-gel method to prepare the core-shell structured BT@TiO2 nanofibers and then utilized to prepare poly(vinylidene fluoride) (PVDF)-based nanocomposites. The study we have performed shows that the dielectric constant of BT@TiO2/PVDF composites with 4 vol% fillers increase to 24 at 1 kHz, accompanied with the low dielectric loss of 0.019. The breakdown strength of BT@TiO2/PVDF composites achieves 128 kV/mm at the content of 2 vol% BT@TiO2 nanofibers, which is 150% of PVDF and 170% of BT/PVDF composites with the same content of fillers. Meanwhile, the tensile stress of BT@TiO2/PVDF composites also reaches the highest value of 44.01 MPa with 2 vol% fillers. In addition, the initial thermal decomposition temperature decreases with the increasing of BT@TiO2 nanofibers.