Multi‐Scaled Dynamic Interactions and Covalent Integration Enable Durable and Self‐Healing Iontronic Skin for Wearable and Implantable Sensing

To address the challenge of signal instability in stretchable electronics under dynamic conditions, this study presents a strain‐durable and self‐healing ion‐electronic skin based on multi‐scaled dynamic interlocking, covalent integration, and ion‐electron multiple conduction. Mechanically tunable and ion‐conductive polyurethane (PU) with excellent component compatibility is synthesized by the free radical polymerization of a photo‐polymerizable ionic liquid with acrylate‐terminated PU with dynamic interactions. Ionic PU infiltrates and mechanically interlaces a rigid carbon nanotube/silver flake conductive framework, a hybrid conductor capable of simultaneous stress dissipation and stable electrical pathways is constructed. This strategy not only provides self‐healing functionality and ion‐electron conduction but also achieves stable sensing performance under different mechanical stimuli, overcoming the long‐standing strain‐sensitivity coupling problem in self‐healable devices. Benefiting from these rational designs, the resulting composite exhibits excellent electromechanical stability with low gauge factor, robust durability, low skin interfacial impedance, and self‐healing ability. More importantly, the reliable long‐term electrophysiological signal monitoring capability is demonstrated in challenging environments such as moisture, vibration, and even in vivo within the bladder. This work offers a new design perspective for developing durable flexible electronics suitable for dynamic biological interfaces.