Core-shell Structured Ag@PDA Nanowires and BT@PDA Nanoparticles for Three-phase Flexible Polymer Nanocomposites with Excellent Dielectric Properties

In this work, core-shell structured polydopamine coated silver nanowires (Ag@PDA NWs) and polydopamine coated BaTiO 3 nanoparticles (BT@PDA NPs) are accurately prepared. Through embedding Ag@PDA NWs and BT@PDA NPs into the P(VDF-HFP) matrix, flexible nanocomposites with high dielectric constant and low dielectric loss are prepared by constructing three-phase structure. The crystal structure, thermal properties and dielectric properties of the nanocomposites are fully investigated. Compared with two-phase nanocomposites, which are composed by Ag@PDA NWs and P(VDF-HFP), the dielectric constant of the three-phase nanocomposites is improved from 28.1 to 67.9. Additionally, owing to the presence of the polydopamine shell, the nanofillers are homogeneously dispersed and the interfacial adhesion between the nanofillers and polymer matrix is also enhanced, leading to the dielectric loss and electric conductivity of three-phase nanocomposites remain relatively low level. Furthermore, the dielectric properties of the three-phase nanocomposites exhibit weak temperature dependence.