Effect of the Dispersion State on the Dielectric Properties in High Energy Density Polymer-Based Nanocomposites

摘要

Polymer composites with PVdF-HFP matrix and BaTiO₃ nanoparticles were prepared with different dispersion states to evaluate the impact of the dispersion state of the nanoparticles on dielectric properties. We observe that the dispersion state has two effects: first, the overall dielectric permittivity is a little higher in aggregated systems than in well-dispersed systems; Second, conductivity, together with a capacitive contribution, increase at low frequencies in aggregated systems as compared to well-dispersed systems. We propose that polarization couplings may enhance the effective permittivity in aggregated systems, and that Maxwell-Wagner-Sillars polarization may also contribute at low frequencies due to local percolation of the particles.