Ultrafast, Autonomous Self-healable Electronic Skin with Mechanosensitive Ion Dynamics

The self-healing properties and mechanosensing capabilities of the human skin has inspired the designs of various self-healing iontronic sensors that respond to pressure, strain, and torsion. Electronic skins based on iontronic materials can be utilized in wide range of applications including wearable technologies, human–machine interfaces, prosthetics, and soft robotics owing to their high noise immunity, exceptional spatial resolution, and excellent response to both static and dynamic stimuli. Conventionally, due to the intrinsic softness of such iontronic materials, they are vulnerable to unexpected mechanical damage, which leads to broken functionalities and limited device longevity. Moreover, the iontronic sensing mechanism most often generates a high initial capacitance due to the limited control of mobile ion dynamics, which results in poor sensitivity. To enhance the control of ion dynamics, previous studies have employed inorganic–based heterogeneous systems to realize ion confinement effect, which resulted in tremendously enhanced device sensitivity. However, the design of such heterogeneous systems can hardly achieve autonomously superior self-healing properties owing to the restricted mobility of polymer chains caused by the slow–moving nanomaterials attached to the polymer. Therefore, designing iontronic systems with simultaneous superior self-healing properties and effective control of ion dynamics, is extremely challenging.<br/> Here, we develop a Cl-functionalized iontronic pressure sensitive material (CLiPS) via the introduction of Cl-functionalized groups (Cl groups) into a polyurethane (PU) matrix, which exhibits not only excellent autonomous self-healing properties but also mechanosensitive ion trap and release mechanism. The design concept involves strategic selection of high chain mobility isophorone diisocyanate and dynamic disulfide bonds to construct the backbone of the PU structure, which are key factors in achieving autonomous self-healing properties of both active matrix and electrodes at room temperature. In addition, with the inclusion of the ionic liquid, a trap and release mechanism is established owing to the ion-dipole interactions between the Cl groups and the ion pairs. On the basis of this unique design approach, we achieved an ultrafast self-healing speed (4.3 µm/min at 25 °C), a high self-healing efficiency (91% within 60 min), and an excellent pressure sensitivity (7.36 kPa^–1). Our CLiPS-based device functioned as a pressure-induced tactile sensor to modulate LED brightness, which validates its capability for applications in next-generation wearable technologies and smarter human-machine interfaces.