3D-Printable gelatin-based organohydrogel for flexible wearable pressure sensors

Growing interest in conductive organohydrogels for wearable flexible strain sensors has significantly increased the demand for their stability and versatility. In this work, stable, and 3D-printed organohydrogels were prepared by utilizing the dynamic hydrogen bonding interaction between Gelatin and dl -Thioctic acid (TA), along with the Hofmeister effect between gelatin and ammonium sulfate. This double network structure endows the hydrogel with outstanding mechanical robustness, excellent low-temperature stability, and rapid gelation behavior suitable for 3D printing. After 200 compression loading-unloading cycles, the organohydrogel retained a remarkably high stress level, maintaining 96 % of its initial stress, and displayed a consistent electrical signal throughout each cycle. Furthermore, even after 7 days at room temperature, the organohydrogel preserved excellent stress (maintained at 92 %), electrical performance, and sensitivity in pressure signal recognition during extended cycle tests. The organohydrogel also supported 3D printing and was used to construct sensor arrays. Its excellent stability and versatility enhanced the potential applications in wearable pressure sensors.