A textile fiber that automatically changes its properties to trap or release heat in response to changes in temperature in its environment was designed by American scientists from the University of Maryland.
Despite decades of innovation in developing fabrics with thermal properties that keep marathon runners cool or hikers warm, no material that modifies its insulating properties for the environment has been created.
This was before the work of biochemist YuHuang Wang and his colleagues, who announced the development of a first fabric able to automatically regulate the amount of heat that passes through the conditions of its environment.
The human body absorbs and loses much of its heat in the form of infrared radiation. This radiation is one of the main ways the body releases heat, and is at the heart of this new technology.
To date, most textiles are able to retain this energy, which helps keep us warm in cold weather.
A challenge overcome
The development of a material capable of releasing energy to passively cool the body remained a challenge for researchers.
In their work published in Science magazine, researchers say they have created a fabric that can do this from a fiber coated with carbon nanotubes.
The new textile is thus made of fibers of two different synthetic materials, one of which absorbs water and the other repels it.
In hot and humid conditions, such as a sweaty body on a summer day, the mesh of the fiber expands and activates the coating of the nanotubes, changing the way the fabric interacts with the infrared and leads to the release of heat.
In cooler and drier conditions, the fabric contracts to prevent heat from escaping. Thus, because the materials contained in the fibers resist and absorb water, they deform when exposed to moisture. This distortion brings the meshes closer to the fiber, which leads to the opening of the “pores” of the fabric and creates a small cooling effect, since it allows the heat to escape.
A quick reaction
The reaction is almost instantaneous. Even before a person realizes that she is hot, the clothes can already refresh her. On the other hand, as his body cools down, the dynamic trigger mechanism will work upside down to retain heat from his body.
Further work is needed before the fabric can be marketed, but according to the researchers, the materials used for the base fiber are readily available and the carbon coating can be easily added during the dyeing process.
Other materials created to date have allowed cooling in various forms, thanks to textiles that reflect sunlight and allow heat from the body to escape. But none of them react to environmental changes or have the ability to regulate both heating and cooling.
