Engineers at Purdue University have developed battery-free smart clothes powered by Wi-Fi that are resistant to laundry. Unlike common wearables, these smart clothes are not powered by a battery, but through a flexible, silk-based coil sewn on the fabric, which means wirelessly. By collecting energy from Wi-Fi or radio waves in the environment, the clothes are capable of powering the circuitry. Smart clothing allows the wearer to check one’s health status and even call for help in case of an accident, but their manufacture is typically challenging because electronics despise water, while clothes need to be washed on a regular basis. By spray-coating smart clothes with highly hydrophobic molecules, any conventional cloth items can be transformed into a battery-free wearable that is repellent to water, oil and mud, and which can be cleaned in the washing machine, Purdue researchers said. The technology is described in an article that has recently appeared in Nano Energy, titled “Washable, breathable, and stretchable e-textiles wirelessly powered by omniphobic silk-based coils,” signed by Marina Sala de Medeiros, Debkalpa Goswami, Daniela Chanci, Carolina Moreno, and Ramses V. Martinez.