Greatly enhanced dielectric permittivity in poly(vinylidene fluoride)-based polymeric composites induced by Na_1/3Ca_1/3Bi_1/3Cu₃Ti₄O₁₂ nanoparticles

Greatly enhanced dielectric permittivity (ε′) in poly(vinylidene fluoride) (PVDF) polymeric composites was induced by incorporating Na_1/3Ca_1/3Bi_1/3Cu₃Ti₄O₁₂ (NCB) nanoparticles. The NCB/PVDF composites were fabricated by conventional mixed powders and hot pressing. Nanosized (NCB-NPs) and microsized-powders (NCB-MPs) prepared, respectively, by chemical combustion and solid state reaction methods were used as fillers. The dispersion of NCB-NPs was quite good in the PVDF matric. A greatly improved ε′ of PVDF-based polymeric composites can be induced by filling with NCB-NPs compared to that of the NCB-MPs/PVDF composite. Interestingly, at 10³ Hz, the nanocomposite with 50 vol% of NCB-NPs can exhibit good dielectric properties with high ε′ of about 210.8 and low loss tangent (tanδ ≈ 0.83). This enhanced ε′ value is much larger than that of PVDF polymer by a factor of ≈20. The increase in ε′ in the nanocomposites is attributed to large interfacial areas and very short interparticle distance. These can cause a great increase in the interfacial polarization intensity.