SiC@SiO2 core@shell filler reinforced polymer composites with high dielectric permittivity and low loss

• Novel SiC@SiO2 core@shell filler with tunable shell thickness has been synthesized.
• SiC@SiO2 with tunable shell thickness showed good compatibility with PVDF matrix.
• SiO2 thickness largely affects dielectric properties of SiC@SiO2/PVDF composites.
• High dielectric permittivity of 52.6 and low loss of 0.031 is achieved at 100 Hz.

This paper reported a novel series of semiconductor–insulator SiC@SiO2 core@shell fillers through a facile calcination process of raw SiC particles under air. Polyvinylidene fluoride (PVDF) composites reinforced by SiC@SiO2 exhibit high dielectric permittivity, low dielectric loss and conductivity. The improved interfacial adhesion and duplex interfacial polarizations are proposed to explain the enhanced dielectric permittivity. The suppressed dielectric loss and electrical conductivity are attributed to the insulating SiO2 interlayer between adjacent SiC fillers. The thickness of SiO2 shell is demonstrated to be vital in determining the dielectric and electrical properties of composites.