Hydrophobic Nanofiber Cellulose-Graphene Films for High-Performance Thermal Management Applications

With the advent of the 5G era, the requirements for the heat dissipation of microelectronic devices are becoming increasingly high. High thermal conductivity composite polymers often require the addition of more thermally conductive fillers, but the increased number of interfaces can lead to unsatisfactory thermal conductivity performance. In this work, a highly thermally conductive film composed of nanocellulose and PyNH2-modified graphene was obtained by evaporation and subsequent hot-pressing. In addition, fluorinated and polydopamine-modified nanodiamonds (F-PDA-ND) were sprayed onto the film to create a hydrophobic layer. Through the improvement of interface interactions, the establishment of graphene orientation structure, and the creation of a hydrophobic layer, the thermal conductivity of the nanocellulose/graphene film can reach 27.06 W·m–1·K–1 (with 10 wt % PyNH2@G content), which is a 21.36-fold increase in thermal conductivity, while also possessing good tensile strength and surface hydrophobic properties. The nanocellulose/graphene thermal conductive film has tremendous potential for applications in the next generation of electronic devices.