Concurrently improving dielectric properties and thermal conductivity of Ni/PVDF composites by constructing NiO shell as an interlayer

Abstract

Polymer dielectrics with super dielectric constant (ε'), low loss as well as high thermal conductivity (TC) are gaining tremendous momentum owing to the ever-increasing demands on microelectronic devices. Introduction core–shell fillers into polymers has been demonstrated as a promising strategy for high-ε' but low loss. Herein, nickel (Ni) particles were encapsulated by an insulating layer of NiO with various thicknesses via controlling calcination times at 550 °C under air, and the as-prepared core–shell Ni@NiO was incorporated into poly(vinyli-dene fluoride) (PVDF). The results verify the formation of a NiO shell outside of the Ni, and manifest that the PVDF with Ni@NiO particles exhibit a high ε', a signally suppressive loss and conductivity, as well as a high-TC compared with raw Ni. The reason can be ascribed to multiple effects of NiO interlayer including the enhancement of interface compatibility and interface polarizations and the blocking of leakage current. Furthermore, the thickness of NiO shell exerts different influences on long-range and short-range charge migration, and it should be rationally tuned to optimize the dielectric properties and TC. This study provides an effective idea to regulate and control the dielectric properties and TC of polymer composites.