Researchers at Nankai University have fabricated a thermal management multi-layer substance that folds or unfolds itself without an external power source.
The details of the findings is published in a paper in Proceedings of the National Academy of Sciences, which explains reasons behind developing the material and details of its performance when tested.
Meanwhile, as scientists world over strive to develop alternative energy sources, other experts are engaged in developing ways to use the energy that has already been developed. In a bid for this, researchers sought an approach to automatically shift a device between its use of solar heating or radioactive cooling, without the need for a secondary power source.
The inspiration to create the material is from Himalayan rabbit, whose fur changes color depending on the season, and leaves of Mimosa pudica plant, whose leaves react to open and close according to changes in temperature.
The material could be made to behave similar to the plant, to allow to switch between thermal devices.
A series of testing led the researchers to come up with a multi-layered substance that worked as it was envisioned. The making of the material involved putting polymer subunits together as a single material. In fact, for design of the subunits, the material used was such that behaved differently depending in the ambient temperature.
For the finished product, an automatic actuator with infrared emissivity placed over a substrate with radiative cooling characteristics. For practical purposes, the material would be lying flat under normal conditions until the surrounding temperature reached a certain point. At this point, the top layer would roll itself into a tube, and expose the dark substrate below.