Highly Oxidation‐Resistant and Self‐Healable MXene‐Based Hydrogels for Wearable Strain Sensor

Abstract Very recently, MXene‐based wearable hydrogels have emerged as promising candidates for epidermal sensors due to their tissue‐like softness and unique electrical and mechanical properties. However, it remains a challenge to achieve MXene‐based hydrogels with reliable sensing performance and prolonged service life, because MXene inevitably oxidizes in water‐containing system of the hydrogels. Herein, catechol‐functionalized poly(vinyl alcohol) (PVA‐CA)‐based hydrogels is proposed to inhibit the oxidation of MXene, leading to rapid self‐healing and superior strain sensing behaviors. Sufficient interaction of hydrophobic catechol groups with the MXene surface reduces the oxidation‐accessible sites in the MXene for reaction with water and eventually suppresses the oxidation of MXene in the hydrogel. Furthermore, the PVA‐CA‐MXene hydrogel is demonstrated for use as a strain sensor for real‐time motion monitoring, such as detecting subtle human motions and handwriting. The signals of PVA‐CA‐MXene hydrogel sensor can be accurately classified using deep learning models.