Bioinspired modified graphite film with superb mechanical and thermoconductive properties

Abstract

Lightweight, tough, heat-resistant and thermoconductive materials are being pursued to replace metals for the thermal management of high-power electrical devices in military, automotive and aerospace fields. In this work, interconnective poly(p-phenylene-2,6-benzobisoxazole) nanofiber network is used to modify graphite film by mimicking the unique multilayered microstructure of natural nacre. The coupling of well-oriented graphite nanosheet and robust 3D nanofiber network not only endows the modified graphite film with superb mechanical property, but also with excellent thermal conduction property. The tensile strength (200.5 ± 1.5 MPa), strain-to-failure (24.3 ± 0.6%), toughness (38.5 ± 0.7 MJ/m3) and folding endurance (>10,000 times) are 16.7-fold, 13.3-fold, 149.2-fold and 333.3-fold higher than those of pure graphite film without modification, respectively. The superb mechanical properties are integrated with excellent thermal properties, including high thermal conductivity (104.5–179.8 W/mK) and good thermal stability (652 °C), as well as nonflammability. Such integration of low density, superb mechanical and thermoconductive properties surpasses 7075-type aluminum alloy, a typical heat dissipation metal material used for thermal management in aerospace devices.