▎ 摘　　要

Dielectric composites with low dielectric loss recently attract increasing concerns of researchers due to the great potential applications in microelectronic devices. In this work, novel hybrid particles, which were composed of barium titanate (BaTiO3), polypyrrole (PPy) and graphene oxide (GO), were prepared through the in situ polymerization of PPy on the surface of BaTiO3 particles and the deposition of BaTiO3@PPy particles on the surface of the GO platelets. Morphology and microstructure characterizations showed that the 'core-shell'-like BaTiO3@PPy particles were prepared and these particles exhibited homogeneous dispersion on the GO platelets. Then, two kinds of poly(vinylidene fluoride) (PVDF)-based composites, including PVDF/BaTiO3@PPy and PVDF/BaTiO3@PPy-GO, were fabricated. Different from the relatively homogenous dispersion of BaTiO3@PPy particles in the whole PVDF/BaTiO3@PPy composites, the BaTiO3@PPy-GO particles exhibited slight aggregation in the PVDF/BaTiO3@PPy-GO composites due to the GO-induced local aggregation of BaTiO3@PPy particles. The two kinds of particles exhibited good nucleation effect and mainly promoted the crystallization of alpha-form PVDF. Electrical conductivity and dielectric property measurements showed that the PVDF/BaTiO3@PPyGO composites had lower electrical conductivity, smaller dielectric loss but higher breakdown strength compared with the PVDF/BaTiO3@PPy composites. The mechanism was mainly attributed to the presence of GO platelets, which restricted the formation of the conductive path in the composites.