Significantly Enhanced Dielectric Properties of Ag-Deposited (In1/2Nb1/2)(0.1)Ti0.9O2/PVDF Polymer Composites

The enhanced dielectric permittivity (epsilon') while retaining a low loss tangent (tan delta) in silver nanoparticle-(In1/2Nb1/2)(0.1)Ti0.9O2/poly(vinylidene fluoride) (Ag-INTO/PVDF) composites with different volume fractions of a filler (f(Ag-INTO)) was investigated. The hybrid particles were fabricated by coating Ag nanoparticles onto the surface of INTO particles, as confirmed by X-ray diffraction. The epsilon' of the Ag-INTO/PVDF composites could be significantly enhanced to similar to 86 at 1 kHz with a low tan delta of similar to 0.044. The enhanced epsilon' value was approximately >8-fold higher than that of the pure PVDF polymer for the composite with f(Ag-INTO) = 0.5. Furthermore, epsilon' was nearly independent of frequency in the range of 10(2)-10(6) Hz. Therefore, filling Ag-INTO hybrid particles into a PVDF matrix is an effective way to increase epsilon' while retaining a low tan delta of polymer composites. The effective medium percolation theory model can be used to fit the experimental epsilon' values with various f(Ag-INTO) values. The greatly increased epsilon' primarily originated from interfacial polarization at the conducting Ag nanoparticle-PVDF and Ag-INTO interfaces, and it was partially contributed by the high epsilon' of INTO particles. A low tan delta was obtained because the formation of the conducting network in the polymer was inhibited by preventing the direct contact of Ag nanoparticles.