Tree Ring-Inspired Fibrous Helix for UV Shielding and Warning Based on Photo-electricity-Acoustic Energy Conversion

Flexible wearable ultraviolet (UV) shielding, monitoring and warning devices have important applications in civil and military fields. However, most flexible wearable UV devices show unsatisfactory performance due to their poor stability and easy failure at large strains. Herein, inspired by tree rings, we engineered a hierarchical composite nanofibrous helix with an alternately stacked Archimedes spiral structure via a cost-effective strategy. Based on a photo-electricity-acoustic energy conversion system, we fabricated an all-in-one device exhibiting strain-insensitive UV protection at 0–500% strain for UV shielding as well as strain-sensitive UV monitoring at 500–1500% strain for UV early warning. Compared with previously reported common nanofibrous membrane devices, the as-prepared composite nanofibrous helix shows great advantages in terms of stability and UV protection, especially at large strains. Furthermore, the helix demonstrates multiple functions of wear resistance, antibacterial properties, biodegradation and knittability. This versatile strategy holds great promise for wearable electronics and multifunctional devices. Graphical abstract