Skin-Mountable and Self-Healable Hydrogel for Strain Sensing

The rapid advancement of wearable electronic devices has heightened the demand for flexible strain sensors with high sensitivity, stretchability, biocompatibility, self-adhesion, self-healing, and water-retention capabilities. However, existing sensors often fall short in these areas, particularly in maintaining stable skin contact, self-repair, and long-term hydration, limiting their practical applications. To address these challenges, we developed a BMIM-BF4/PEDOT:PSS/gelatin/PVA hydrogel (BPGPH) with a double-network structure. This hydrogel exhibits exceptional mechanical properties, enduring up to 400% strain and 318 kPa stress, and maintains its integrity and performance over 12 days due to glycerol-enhanced water retention. With a gauge factor of 0.29, BPGPH demonstrates high sensitivity across 0–300% strain, enabling precise detection of human motions. Its self-adhesion and self-healing properties, driven by abundant hydroxyl groups, further enhance its suitability for applications in gesture recognition and human–computer interaction. The synergistic effect of ionic liquids and conductive polymers ensures stable conductivity, while the multinetwork structure provides robustness and flexibility. These features make BPGPH a promising candidate for next-generation wearable sensors in healthcare monitoring, human–machine interfaces, and sports performance tracking.