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

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 (approximate to 496 kPa, 2400%), robust adhesion (approximate to 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.