Scientists have created a prototype garment to demonstrate dynamic thermal radiation control within a piece of clothing by utilizing the thermal properties and flexibility of graphene. The development also opens the door to new applications such as interactive infrared displays and covert infrared communication on textiles.
The human body radiates energy in the form of electromagnetic waves in the infrared spectrum (known as blackbody radiation). In a hot climate, it is desirable to make use of the full extent of the infrared radiation to lower the body temperature, which can be achieved by using infrared-transparent textiles. As for the opposite case, infrared-blocking covers are ideal to minimize the energy loss from the body. Emergency blankets are a common example used to deal with treating extreme cases of body temperature fluctuation. The team demonstrated the dynamic transition between two opposite states by electrically tuning the infrared emissivity (the ability to radiate energy) of graphene layers integrated onto textiles.
One-atom-thick graphene has uses in commercial products including batteries, mobile phones, sporting goods, and automotive. The new research demonstrated that the smart optical textile technology can change its thermal visibility. The technology uses graphene layers to control thermal radiation from textile surfaces.
The ability to control the thermal radiation is a key necessity for several critical applications such as temperature management of the body in excessive temperature climates. Maintaining these functionalities as the surroundings heat up or cool down has been a challenge. The current work can enable new technologies operating in the infrared and other regions of the electromagnetic spectrum for applications including textile displays, communications, adaptive spacesuits, and fashion.
This work built on the same group’s previous research using graphene to create thermal camouflage, which was able to fool infrared cameras. The new research can also be integrated into existing massmanufactured textile materials such as cotton. To demonstrate, the team developed a prototype product within a t-shirt, allowing the wearer to project coded messages invisible to the naked eye but readable by infrared cameras.
The next step is to address the need for dynamic thermal management of earth-orbiting satellites, which experience excesses of temperature when they face the Sun and they freeze in the Earth’s shadow. The technology could enable dynamic thermal management of satellites by controlling the thermal radiation and regulating the satellite temperature on demand.