Graphene woven fabric-reinforced polyimide films with enhanced and anisotropic thermal conductivity

Due to the growing needs of thermal management in modern electronics, polyimide-based (PI) composites are increasingly demanded in thermal interface materials (TIMs). Graphene woven fabrics (GWFs) with a mesh structure have been prepared by chemical vapor deposition and used as thermally conductive filler. With the incorporation of 10-layer GWFs laminates (approximate 12 wt%), the in-plane thermal conductivity of GWFs/PI composite films achieves 3.73 W/mK, with a thermal conductivity enhancement of 1418% compared to neat PI. However, the out-of-plane thermal conductivity of the composites is only 0.41 W/mK. The in-plane thermal conductivity exceeds its out-of plane counterpart by over 9 times, indicating a highly anisotropic thermal conduction of GWFs/PI composites. The thermal anisotropy and the enhanced in-plane thermal conductivity can be attributed to the layer-by-layer stacked GWFs network in PI matrix. Thus, the GWFs-reinforced polyimide films are promising for use as an efficient heat spreader for electronic cooling applications.