The ability to remain invisible has long fascinated mankind and has been used often by the military in war zones. The armed forces make use of various forms of camouflage to remain invisible during war and protect personnel and equipment from being noticed by enemies. In practice, this means applying colour and materials to military uniforms and equipment of all kinds, including armoured vehicles, ships, aircraft, artillery and firearms, either to conceal it from observation (crypsis), or to make it appear as something else (mimicry).
With the advent of modern technology, however, simply remaining hidden from visible light is not enough to render oneself invisible. Human bodies radiate heat in a manner that allows infrared (IR) cameras to effortlessly identify soldiers from their surroundings (even at night).
To address this challenge, Prof. Adina Luican-Mayer partnered with the Department of National Defense (DND) through their Innovation for Defence Excellence and Security (IDEaS) challenge program to develop a unique and state-of-the art technology called 'adaptive thermal camouflage' that is based on multilayer graphene films. As starting material, her team used ultrathin graphene films (100 atomic layers), which have the special property that external stimuli such as an electric field, or changes in the number of electrons, can be used to control their optoelectronic properties. Prof. Luican-Mayer’s team demonstrated innovative devices in which the thermal emissivity of a graphene film can be controlled by simply applying a voltage between an electrode and the graphene film, separated by a membrane containing ionic liquid. The electric field in these devices moves the ions from the membrane in between the graphene layers, changing the graphene film’s optical properties or the type of infrared radiation it emits. This way, her group successfully demonstrated the ability to conceal objects from infrared cameras.
These novel multilayer graphene films were deployed on rigid as well as on flexible platforms, including textiles. This technology could help protect the lives of soldiers serving in the Canadian armed forces on international missions in war zones.
This research partnership also opens avenues for the development of new flexible textile technologies for national security applications. Prof. Luican-Mayer's team working on this project included postdoctoral fellow Dr. Saher Hamid alongside undergraduate students Tyler Dacosta, Kai Kang and Antoine Labbé.
