TiO2@Ag/P (VDF-HFP) composite with enhanced dielectric permittivity and rather low dielectric loss

摘要

Ag-loaded TiO2 hybrid particles (TiO2@Ag) were synthesized as fillers by using an ethylene glycol reduction method. Based on this, the TiO2@Ag/P(VDF-HFP) hybrid films were prepared by embedding TiO2 nanoparticles in a poly(vinylidene fluoride-co-hexafluoropropylene) [P(VDF-HFP)] matrix. Morphology and thermal analysis show that the introduction of TiO2@Ag does not disrupt the continuity of the polymer matrix, while the strong interaction between fillers and matrix influences the crystallization process of the composite. The adhesion of Ag to TiO2 efficiently separates the Ag particles from connecting and suppresses the formation of a conductive network, and the ultra-small Ag nanoparticles "trap" the carriers due to coulombic blockade and quantum confinement effect, which results in low dielectric loss and electrical conductivity of the composites. As a consequence, the dielectric permittivity of polymer nanocomposites was enhanced by 300% over the P(VDF-HFP) matrix at a filler content of 30 vol% while maintaining a rather low dielectric loss (0.037 at 1 kHz), demonstrating promising applications in electronic devices.