Self‐Adhesive Gelatin/Slide‐Ring Double‐Network Hydrogel for Human Motion Sensing and Morse Code Communication

Abstract Hydrogels emerge as highly promising candidates for wearable electronics due to their moldability and biocompatibility. However, hydrogel‐based wearable electronics often suffer from poor mechanical properties and limited adhesion, pose significant challenges to their practical application. Herein, a conductive, stretchable, and self‐adhesive gelatin/slide ring hydrogel (SRH) with a double‐network (DN) structure is developed by incorporating a polyrotaxane (PR) based cross‐linker in the hydrogel with the gelatin (GEL) network. The water‐soluble allylic PR (APR) cross‐linkers are prepared from the cyclodextrin‐based PR via a simple one‐step method. Additionally, the effect of APR cross‐linkers with different sliding capabilities on the mechanical properties of SRH is further investigated aiming to optimize performance. The optimized SRH achieves a balance between toughness (2226 kJ m −3 ) and rigidity (154 kPa), along with high stretchability (3048%) and strong adhesion to various substrate materials. More importantly, this DN hydrogel is demonstrated as a human motion sensor capable of Morse code communication. This work not only advances the understanding of slidable PR cross‐linker applications but also paves the way for innovative hydrogels tailored for high‐performance wearable electronics, broadening their scope and functionality in real‐world use.