▎ 摘　　要

In this work, the role of graphene flake size on the properties of poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) composites was studied. Graphene flakes were added to PVDF-HFP using a solution mixing and molding process. By increasing graphene particle size and its concentration in the composites, higher electrical conductivity, in-plane thermal conductivity, and elastic modulus were achieved. Maximum tensile strength was obtained for the composites with average graphene flake size of 2, 5, and 7 mu m at graphene concentrations of 10 wt%, 5 wt%, and 20 wt%, respectively. Thick flexible composite films (0.2-0.4 mm) with ultra-high in-plane electrical conductivity (similar to 4500 S/m), in-plane thermal conductivity (similar to 26 W/m/K), and tensile strength (similar to 50 MPa) were obtained for the samples containing the graphene flakes with a larger average particle size of 7 mu m. To our knowledge, the first two values are larger than any other values reported in the literature for PVDF-based composites.