Highly wearable, machine-washable, and self-cleaning fabric-based triboelectric nanogenerator for wireless drowning sensors

Abstract

Rapid developments of artificial intelligence have increasingly necessitated wearable and functionalized fabric-based triboelectric nanogenerators (F-TENGs). However, conventional F-TENGs are limited by low outputs, poor durability and washability. In this study, through simple liquid-phase fluorination with homemade urethane perfluorooctyl silane (NHCOO-PFOTS), functional fabrics were fabricated for highly wearable and machine-washable F-TENGs. By introducing fluorine atoms, the fabrics possess strong electron-accepting ability, excellent waterproof and anti-soil performances. Besides, fluorination provides excellent durability for F-TENGs since chemicals reacted inside the fibers and formed long-chain molecules that will not disappear upon subsequent washing and daily abrasion. F-TENG composed of fluorinated silk and nylon fabrics yielded a maximum output power of 2.08 W·m−2 at 10 MΩ with negligible decay after 45,000 cycles of contact-separation motions and 70 h of washing. Fluorinated silk can maintain hydrophobic (contact angle > 140°) in extreme environments for long durations. In addition, the F-TENG developed herein exhibits excellent anti-wear performances and self-healing of hydrophobicity and triboelectric performances through heating treatment. Further, F-TENGs sewed on clothing can drive a digital watch using electricity generated by arm swinging. A wireless drowning sensor was designed by utilizing human motion energy with a water-conducted switch in the circuit. The sensor gets triggered by water and instantaneously sends out real-time alarms and notifications to mobile devices. The excellent outputs and practicability of fluorinated fabrics make them excellent candidates for self-powered smart clothes and wearable devices for drowning prevention.