Highly Stretchable, Transparent, Self‐Healing Ion‐Conducting Elastomers for Long‐Term Reliable Human Motion Detection

Abstract The flexible electronic sensor is a critical component of wearable devices, generally requiring high stretchability, excellent transmittance, conductivity, self‐healing capability, and strong adhesion. However, designing ion‐conducting elastomers meeting all these requirements simultaneously remains a challenge. In this study, a novel approach is presented to fabricate highly stretchable, transparent, and self‐healing ion‐conducting elastomers, which are synthesized via photo‐polymerization of two polymerizable deep eutectic solvents (PDESs) monomers, i.e., methacrylic acid (MAA)/choline chloride (ChCl) and itaconic acid (IA)/ChCl. The as‐prepared ion‐conducting elastomers possess outstanding properties, including high transparency, conductivity, and the capability to adhere to various substrates. The elastomers also demonstrate ultra‐stretchability (up to 3900%) owing to a combination of covalent cross‐linking and noncovalent cross‐linking. In addition, the elastomers can recover up to 3250% strain and over 94.5% of their original conductivity after self‐healing at room temperature for 5 min, indicating remarkable mechanical and conductive self‐healing abilities. When utilized as strain sensors to monitor real‐time motion of human fingers, wrist, elbow, and knee joints, the elastomers exhibit stable and strong repetitive electrical signals, demonstrating excellent sensing performance for large‐scale movements of the human body. It is anticipated that these ion‐conducting elastomers will find promising applications in flexible and wearable electronics.