Mechanically Robust, Self‐Healable, and Cryotolerant GelMA Hydrogel for Wearable Tactile Sensors with Enhanced Durability, Lifetime, and Environmental Stability

Gelatin methacryloyl (GelMA) hydrogels are promising for wearable tactile sensors due to their biocompatibility, tissue-mimic softness and conductivity, yet restricted by mechanical property, structure damage, dehydration, and freezing during usage. Herein, a mechanically robust, self-healable, moisturizing, cryotolerant and adhesive GelMA hydrogel is developed by incorporating polyvinyl alcohol, acrylic acid, sodium tetraborate, and glycerol into GelMA matrix via a photoinitiated polymerization process. This unique approach overcomes the chemical-mechanical conflictions among different molecules, and contributes to remarkable stretchability (≥220%, 5.5-fold higher), elasticity (≈91.9% recovery), autonomous self-healing within wide temperature range (from -40°C to 25°C), adhesion (≥23.5 kPa), moisture retention (≥81% after 10 d) and anti-freezing (-55.4°C) properties, significantly outperforming previous GelMA. Based on this, an omni-healable ionotronic pressure sensor is constructed, featuring high sensitivity within broad pressure range (0-25 kPa), rapid recovery time, long-term stability (≈120 h), excellent durability and performance self-repairing (≈100% sensing range recovery) under subzero temperature. Sensitively and consistently monitoring of various physiological signals under harsh conditions, such as multiple structure damages, long period (≥5 d) and subzero temperatures (≤-38.2°C) highlights its prominent durability, lifetime and environmental-stability, demonstrating great promise toward practical application.