Researchers at Duke University in the United States have developed a material that holds heat when the body is dry but opens a sort of valves when you start sweating. When the sweat has evaporated, the valves close again and keep your body warm. The opening and closing of the microscopic valves occur automatically when heat increases or decreases, using no external power source such as batteries.
Of course, there are already clothes that "breathe", but this method should be much more effective at getting rid of sweat. In tests conducted by the researchers, the new material was 16 percent better at retaining heat and 14 percent better at emitting heat than today's materials.
An advantage of the material is that it becomes easier to know how to dress on occasions when the body may quickly shift between being hot and cold.
"People who ski or hike in cooler weather often have several layers so that they can adjust how much heat their clothes capture as the body warms up. By placing pieces of our material in strategic places, it can emit heat when needed. In this way, one garment would be enough for all occasions", says Po-Chun Hsu, one of the researchers behind the new material, in a press release.
Another advantage is that the material can release heat where it is generated on the body and not just on certain parts. A method that is otherwise common when manufacturers insert zippers, for example under the arms.
"We want the parts of the body that are sweating to be ventilated and it is not necessarily the armpits. The chest and back area often need more ventilation and putting zippers there is so impractical that it is just as good to take off the garment completely", says Po-Chun Hsu.
The material is basically a nylon fabric that is cut up in a special way and then covered with a silver surface. The silver surface is only 50 nanometers thick, 2,000 times thinner than a sheet of paper, but it is enough to give the material its unique qualities.