A coating-free superhydrophobic sensing material for full-range human motion and microliter droplet impact detection

Traditional waterproofing strategies (e.g. plastic seals, superhydrophobic coatings) of strain sensors greatly limit their sensing performance (e.g., sensitivity, working-range, and working-life). Here a unique ultra-stretchable, coating-free superhydrophobic material is developed for high-performence strain sensing in harsh environments. This material integrates high sensitivity (GF of 2.1 to 214), wide sensing range (up to 447% strain), low resolution (<0.2% strain), dynamic durability (over 10,000 stretching cycles at 50% strain), and ultra-robust superhydrophobicity (mechanically, chemically, thermally, and UV impervious) in a single system, outperforming most of reported waterproof sensors. Such remarkable sensing materials can detect full range human movement, pulse rate and vocal fold vibration. The sensing material is designed to be superhydrophobic throughout its bulk material for work in harsh environments (water, corrosive liquid, high humidity, etc.). More importantly, the superhydrophobicity enables the highly sensitive sensor to detect microliter droplets impact with minimized energy loss. Thus, this sensing material should find many potential applications in wearable electronics, measurement platform, rainfall monitoring and intelligent irrigation system.