Tough Liquid‐Free Ionic Conductive Elastomers with Robust Adhesion and Self‐Healing Properties for Ionotronic Devices

Abstract Polymerizable deep eutectic solvent (PDES) as a newly emerging type of liquid‐free ionic conductive elastomer is considered to be the most attractive candidate for the next generation of ionotronic devices. However, it remains a huge challenge to integrate high ionic conductivity, excellent mechanical properties, good self‐healing capacity, and robust adhesion into a single material that satisfies the stringent demand of the ionotronic devices in various scenarios. Herein, a liquid‐free ionic elastomer is constructed by incorporating tannic acid‐encapsulated cellulose nanocrystals (TA@CNC) as multifunctional hydrogen bond donors (HBDs) along with poly(acrylic acid) (HBDs) and choline chloride (hydrogen bond acceptors, HBAs) to form a dynamic cross‐linking network through multiple dynamic hydrogen bonds. The presence of the rigid crystalline regions and the sufficient dynamic interaction sites on the TA@CNC endow the resultant elastomers (ACTC) with superior mechanical properties (≈496 kPa, 2400%), robust adhesion (≈68.6 kPa), and good self‐healing property. Benefiting from the above integrated features, the wearable sensors by harnessing the ACTC as a resistance sensing module is constructed that provide unaltered sensing performance under off‐axial deformation (twisting and prick). Additionally, the capacitance pressure sensor with good stability for force distribution is developed, opening up a new avenue for the development of ionotronic devices.