Synergy improvement of dielectric properties and thermal conductivity in PVDF composites with core-shell structured Ni@SiO_2

摘要

Developing a high dielectric constant (ε_r) polymer dielectrics with low dielectric loss and high thermal conductivity (TC) is still continuous demands for advanced electrical power systems. Herein, nickel (Ni) particles were encapsulated by silica (SiO_2) via a sol-gel process using sodium silicate as a precursor, and the obtained core-shell Ni@SiO_2 powders were blended into poly(vinyli-dene fluoride) (PVDF) to investigate the effects of SiO_2 insulating layer and its thickness on dielectric properties and TC of composites. Compared with pristine Ni, the Ni@SiO_2/PVDF composites exhibit a superior ε_r, and remarkably suppressed loss and conductivity, attributable to the SiO_2 interlayer between the core Ni particles which effectively prevents them from direct contacts and significantly reduces the leakage loss. Moreover, the Ni@SiO-2/PVDF composites still possess a high TC owing to the restrained thermal interfacial resistance and enhanced interfacial compatibility between the fillers and the matrix. The developed Ni@SiO_2/PVDF composites with high κ and TC but low loss are potential for microelectronic industry.