A demonstration of graphene thermal smart materials. Image: The University of Manchester.
A demonstration of graphene thermal smart materials. Image: The University of Manchester.

New research on the two-dimensional (2D) material graphene has allowed researchers to create smart adaptive clothing that can lower the body temperature of the wearer in hot climates.

A team of scientists from the University of Manchester's National Graphene Institute in the UK has created a prototype garment to demonstrate dynamic thermal radiation control within a piece of clothing by utilizing the remarkable thermal properties and flexibility of graphene. This development also opens the door to various new applications on textiles, such as interactive infrared displays and covert infrared communication.

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 full use of this infrared radiation to lower the body temperature by utilizing infrared-transparent textiles. In cold climates, infrared-blocking covers are ideal for minimizing energy loss from the body; emergency blankets are a common way to treat extreme cases of body temperature fluctuation.

The collaborative team of scientists demonstrated the dynamic transition between these two opposite states – infrared transparent or blocking – by electrically tuning the infrared emissivity (the ability to radiate energy) of the graphene layers integrated onto textiles.

One-atom thick graphene was first isolated and explored in 2004, by a team from the University of Manchester led by Andre Geim and Kostya Novoselov. Its potential uses are vast, and research has already led to leaps forward in commercial products such as batteries, mobile phones, sporting goods and cars.

The new research, reported in a paper in Nano Letters, demonstrates a smart optical textile technology that can change its thermal visibility by using graphene layers to control thermal radiation from textile surfaces.

"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," said Coskun Kocabas, who led the research. "Thermal blankets are a common example used for this purpose. However, maintaining these functionalities as the surroundings heat up or cool down has been an outstanding challenge.

"The successful demonstration of the modulation of optical properties on different forms of textile can leverage the ubiquitous use of fibrous architectures and enable new technologies operating in the infrared and other regions of the electromagnetic spectrum for applications including textile displays, communication, adaptive space suits and fashion."

This study built on the same group's previous research using graphene to create thermal camouflage that could fool infrared cameras. The new research can also be integrated into existing mass-manufacture textile materials such as cotton. To demonstrate, the team developed a prototype product within a t-shirt that allowed the wearer to project coded messages invisible to the naked eye but readable by infrared cameras.

"We believe that our results are timely showing the possibility of turning the exceptional optical properties of graphene into novel enabling technologies. The demonstrated capabilities cannot be achieved with conventional materials," said Kocabas.

"The next step for this area of research is to address the need for dynamic thermal management of Earth-orbiting satellites. Satellites in orbit experience excesses of temperature, when they face the Sun, and they freeze in the Earth's shadow. Our technology could enable dynamic thermal management of satellites by controlling the thermal radiation and regulate the satellite temperature on demand."

"This is a beautiful effect, intrinsically routed in the unique band structure of graphene. It is really exciting to see that such effects give rise to the high-tech applications," said Novoselov, who was also involved in the research.

This story is adapted from material from the University of Manchester, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.