Bioinspired Flexible Kevlar/Hydrogel Composites with Antipuncture and Strain-Sensing Properties for Personal Protective Equipment

Currently, multifunction has become an essential direction of personal protective equipment (PPE), but achieving the protective effect, flexibility, physiological comfort, and intelligent application of PPE simultaneously is still a challenge. Herein, inspired by the meso-structure of rhinoceros skin, a novel strategy is proposed by compounding an ammonium sulfate ((NH₄)₂SO₄) solution soaked gelatin hydrogel with the high weight fraction and vertically interwoven Kevlar fibers to manufacture a flexible and wearable composite with enhanced puncture resistance and strain-sensing properties. After (NH₄)₂SO₄ solution immersion, the hydrogel's tensile strength, toughness, and fracture strain were up to 3.77 MPa, 4.26 MJ/m³, and 305.19%, respectively, indicating superior mechanical properties. The Kevlar/hydrogel composites revealed excellent puncture resistance (quasi-static of 132.06 N and dynamic of 295.05 N), flexibility (138.13 mN/cm), and air and moisture permeability (17.83 mm/s and 2092.73 g m^-2 day^-1), demonstrating a favorable balance between the protective effect and wearing comfort even after 7 days of environmental exposure. Meanwhile, salt solution immersion endowed the composite with excellent strain-sensing properties at various bending angles (30-90°) and frequencies (0.25-1 Hz) and allowed it to monitor different human motions directly in real-time. The rhinoceros-skin-inspired Kevlar/hydrogel composites provide a simple and economical solution for antipuncture materials that combine high protective effects, a comfortable wearing experience, and good strain-sensing properties, promising multifunctional PPE in the future.