Graphene Based Adaptive Thermal Camouflage

TL;DR

This paper introduces a flexible, lightweight graphene-based device that actively controls thermal emission in real-time, enabling adaptive thermal camouflage and potential applications in IR optics and space heat management.

Contribution

It presents a novel electro-modulation method for IR emissivity control using multilayer graphene and ionic liquids, achieving real-time adaptive thermal camouflage.

Findings

Devices can reconfigure thermal appearance within seconds.

Able to disguise hot objects as cold and vice versa.

Light, thin, and ultra-flexible design suitable for various surfaces.

Abstract

In nature adaptive coloration has been effectively utilized for concealment and signaling. Various biological mechanisms have evolved that can tune the reflectivity for visible and ultraviolet light. These examples inspire many artificial systems for mimicking adaptive coloration to match the visual appearance to their surroundings. Thermal camouflage, however, has been an outstanding challenge which requires an ability to control of the emitted thermal radiation from the surface. Here we report a new class of active thermal surfaces capable of efficient real-time electrical-control of thermal emission over the full infrared (IR) spectrum without changing the temperature of the surface. Our approach relies on electro-modulation of IR absorptivity and emissivity of multilayer graphene via reversible intercalation of nonvolatile ionic liquids. The demonstrated devices are light (30 g/m2), thin (<50 um) and ultra-flexible which can conformably coat their environment. In addition, combining active thermal surfaces with a feedback mechanism, we demonstrate realization of an adaptive thermal camouflage system which can reconfigure its thermal appearance and blend itself with the thermal background in a few seconds. Furthermore, we show that these devices can disguise hot objects as cold and cold ones as hot in a thermal imaging system. We anticipate that, the electrical control of thermal radiation will impact on a variety of new technologies ranging from adaptive IR optics to heat management for outer space applications.