The more clothing that you wear, the warmer you are … right? Well actually, scientists have developed a new textile that both warms wearers in cold environments, and cools them down when things heat up.

The experimental material was developed at China’s Huazhong University of Science and Technology, by a team led by Prof. Guangming Tao. It’s made by first freeze-spinning silk and chitosan, forming fibers with a porous microstructure – chitosan, incidentally, is a highly useful natural compound found in crustacean shells.

Next, the pores within the fibers are filled with polyethylene glycol (PEG), which is a phase-change material that takes the form of a liquid when warm, and a solid when cool. Finally, the fibers are coated with an organic polymer known as polydimethylsiloxane, to keep the PEG from leaking out while in its liquid state.