Mechanism of enhanced dielectric performance in Ba(Fe0.5Ta0.5)O3/poly(vinylidene fluoride) nanocomposites

An organic-inorganic 0-3 nanocomposites, in which nanoparticles (0-dimensional) are embedded in a 3-dimensionally connected polymer matrix, rapidly emerged for a number of advanced engineering applications. The nanocomposites with enhanced dielectric performance is realized by employing Ba(Fe0.5Ta0.5)O3 (BFT) with giant dielectric constant (ε′) as a ceramic filler and poly(vinylidene fluoride) (PVDF) as a polymer matrix. The dense nanocomposites use the hot-press process, which can eliminate the porosity. Experimental data shows that dielectric constant of the nanocomposites with 60 vol% of BFT can reach 97 at 100 Hz, which is attributed to the individual dielectric constant of BFT and PVDF, and enhanced interfacial polarization. Meanwhile, the soft percolation regime is found at the volume filling fractions of BFT between 0.2 and 0.3, which also plays an important role in enhanced dielectric constant. Different theoretical models are applied to predict the dielectric constants of the nanocomposites. Furthermore, the introduction of BFT nanoparticles improves the temperature stability of dielectric constant in the temperature range from 20 °C to 120 °C.