Fabrication and excellent properties of polyvinylidene fluoride/graphene composite films as thermal interface materials

The growing concern about thermal conductivity and electromagnetic shielding m electronic equipment has promoted the development of interfacial film materials. In this work, polyvinylidene fluoride (PVDF)/graphene composite films with different graphene contents were fabricated by high-energy ball milling, cold isostatic pressing, scraping and coating, successively. High-energy ball milling is beneficial to the dispersion of graphene powder, while cold isostatic pressing can greatly enhance thermal conductivity and mechanical strength by reducing the voids in the film and increasing the contact area of graphene sheets. The thermal conductivity, tensile strength and electromagnetic shielding properties of the films were carefully investigated and compared. It was demonstrated that the thermal conductivity increased from 0.19 W·m-1·K-1 for pure PVDF to 103.9 W·m-1·K-1 for the composite film with PVDF:graphene=l:3. Meanwhile the electromagnetic shielding efficiency can reach 36.55 dB. The prepared PVDF/ graphene composite films exhibit outstanding overall performance and have the potential for practical applications.