Multi-dimensional fillers collaborative optimization of thermal conductivity of PVDF-based composites

The continuous miniaturization and integration of electronic chips lead to a large amount of waste heat generated under high-power working conditions. Polyvinylidene fluoride (PVDF) can be used as a thermal management material of electronic devices due to its low dielectric constant, high-thermal stability, and good scalability. However, the ultra-low intrinsic thermal conductivity of PVDF restricts its widespread application in the field of electronic component heat dissipation. Constructing thermal conduction pathways with inorganic fillers is a key approach to addressing the thermal conductivity of PVDF. In this work, two-dimensional boron nitride nanosheets (BNNSs) and one-dimensional carbon nanotubes (CNTs) are selected as fillers to prepare PVDF composite films, constructing effective thermal paths between inorganic fillers and PVDF, as well as between inorganic fillers. When the mass fraction of BNNS is 40 wt. %, the thermal conductivity of the binary composite film can reach 1.638 W/(m K). This value increases to 2.87 W/(m K), which is 22.9 times higher than that of pure PVDF, when an additional 3 wt. % mass fraction of CNT is added, showing that the synergistic action of the hybrid, thermally conductive fillers can significantly enhance the thermal conductivity by creating thermal bridges between 2D fillers. At the same time, the prepared ternary composite film has good mechanical properties, the tensile strength is 9.54 MPa, and the elastic modulus is 608.21 MPa. It provides a new way for the preparation of high-thermal conductivity thin films with the potential of flexible heat dissipation devices.