Facile synthesis of 3–0 type dielectric composites using thermocurable phenolic-resin@BaTiO3 core–shell particles prepared by pulsed laser deposition

Abstract

We demonstrate that a 3–0 type bulk composite that reaches the effective permittivity of the Hashin–Shtrikman upper bound can be produced using thermocurable phenolic-resin@BaTiO3 particles. Core–shell particles with an average shell thickness of 79 nm were prepared using a pulsed laser deposition (PLD) apparatus equipped with a rotary drum. Microstructural analysis revealed that a three-dimensionally connected BaTiO3 network was constructed in the bulk composite prepared by thermocuring the PLD-processed core–shell powder. Compared with the phenolic resin, the bulk composite containing 2.3 vol% BaTiO3 showed an 15.4 % increase in effective permittivity; in addition, the dielectric loss and insulation resistance of the composite were not deteriorated. By contrast, a conventional 0–3 type bulk composite, which was composed of randomly dispersed isolated BaTiO3 particles with an average particle size of 100 nm (similar to the thickness of the shell formed by PLD processing) in a phenolic resin matrix, showed an increase in relative permittivity of only 2.2 %. The results suggest that the proposed process would be an effective method for preparing organic–inorganic bulk composites with the 3–0 type structure with various enhanced physical properties (including relative permittivity) that follow the additive law.