Insights into concomitant enhancements of dielectric properties and thermal conductivity of PVDF composites filled with core@double-shell structured Zn@ZnO@PS particles

In order to synchronously improve dielectric permittivity (epsilon '), breakdown strength (E-b), and thermal conductivity (TC) while inhibiting dissipation factor (tan delta) of raw Zn (Zinc)/PVDF (poly[vinylidene fluoride]) composites, two kinds of core-shell structured particles of Zn@ZnO (zinc oxide) and Zn@ZnO@PS (polystyrene) were synthesized by high-temperature oxidation followed by suspension polymerization, then they were composited with PVDF to elaborately generate morphology-controllable high-epsilon ' but low loss, and high TC composites. The results confirm that both the Zn@ZnO/PVDF and Zn@ZnO@PS/PVDF composites show markedly improved epsilon ', suppressed tan delta and conductivity over the original Zn/PVDF because of the induced multiple polarizations in the Zn@ZnO and Zn@ZnO@PS configurations and the barrier effect of constructed shells on direct contact of Zn particles. The second organic PS shell inhibits the loss and conductivity due to its high-electrical resistivity, and further boosts the E-b and TC of the composites owing to enhanced interfacial compatibility between the Zn@ZnO and PVDF, which lessens the local electric field distortion and concentration, and therefore, promotes phonon transport across the interfaces through suppressing the thermal interfacial resistance. The prepared Zn@ZnO@PS/PVDF with a high E-b and epsilon ' but low tan delta, as well as enhanced TC, exhibit appealing potential applications in microelectronic devices and power equipment.