Development of highly conductive polymeric nanocomposite films on the surfaces of composites against lightning strikes

The most of the early airplane skins were made primarily of aluminum alloy sheets that are very good conductors of electricity. If a lightning strikes on Al surface, the current of lightning easily flows from the point of impact, and is evenly distributed throughout the surface without interruption or diversion to the interior of the aircraft. Recently, composite aircrafts have been built to increase the fuel efficiency and strength of the military and commercial aircrafts, and reduce the overall weight and corrosion. However, composite aircraft face the lightning strike problems because of the fact that the composite materials are either not conductive (e.g., fiberglass and Kevlar) or are significantly less conductive (e.g., carbon fiber) especially when they are embedded into a polymeric matrix. Thus, the lack of conductivity causes the failure when the lightning strike happens. For this reason, lightning strike protection has been vitally important for the new generation of composite aircrafts. Graphene and indium tin oxide (ITO) nanoflakes are excellent materials in terms of electrical conductivity and electromagnetic field shielding property. This paper states the current lightning strike protection techniques and provides some experimental evidence of graphene and ITO based nanocomposite coatings on the carbon fiber reinforced composites. This approach may overcome the problem of lightning strike on the composite aircrafts.