A fabric that can adapt to changing weather conditions, keeping its wearer cool in the heat of midday but warm when an evening storm blows in. “Smart textiles” that can warm or cool the wearer are nothing new, but typically, the same fabric cannot perform both functions.

The researchers freeze-spun silk and chitosan, a material from the hard outer skeleton of shellfish, into colored fibers with porous microstructures. They filled the pores with polyethylene glycol (PEG), a phase-changing polymer that absorbs and releases thermal energy. Then, they coated the threads with polydimethylsiloxane to keep the liquid PEG from leaking out. The resulting fibers were strong, flexible and water-repellent.

[Source: American Chemistry Society. 15 April 2020]