Enhancing dielectric property and multi-interface polarization of poly(vinylidene fluoride)/Ni-embedded CaCu3Ti4O12 fibers composites tailored by magnetic field

Abstract

In the realm of advanced electrical equipment and systems, polymer nanocomposites possess significant application value due to their excellent dielectric properties. Metal@ceramic fillers with a core-shell structure can enhance the dielectric constant (ε′) of polymer nanocomposites; however, their application is limited by the high dielectric loss (tanδ). A magnetic field tailoring strategy is introduced in this article to significantly improve the dielectric properties of poly(vinylidene fluoride) (PVDF) composites. Magnetic CaCu3Ti4O12–Ni (CN) composite fibers are formed by embedding Ni nanoparticles within CaCu3Ti4O12 (CCTO) fibers. Furthermore, the CN fibers are horizontally orientated in the PVDF matrix by tailoring the optimal magnetic field to 1.0 T–150 ℃. This results in a significant increase in the ε′ of 25, which is 92 % and 194 % higher than that of a CN fiber without magnetic field treatment and pure PVDF, respectively, while maintaining a low tanδ of 0.08. Experimental and simulation results indicate that the magnetic orientation tailoring enhances the multi-interface polarization, especially the inner interfacial polarization (△Pin) at the CCTO/Ni interfaces, dominantly improving dielectric performance, as evidenced by the high interfacial polarization strength, △ε2 ∼ 141.51, the low activation energy, Ea ∼ 0.81 eV, and the large △Pin ∼ 1.06×104 μC/m2. This magnetic orientation tailoring strategy offers a new paradigm and significant guidance for the development of polymer dielectrics with exceptional dielectric properties.