Self-healing, adhesive, and antioxidant MXene-reinforced conductive hydrogels for stain sensor

This work develops a dynamic boronic-ester-bond-based hydrogel system for self-healing and simultaneously achieves MXene’s antioxidant protection with polyanionic salt of sodium carboxymethyl cellulose (CMC). By cross-linking poly(vinyl alcohol) (PVA) and polyacrylic acid (PAA) to obtain a polymer backbone, and using CMC and borate modified MXene (MCB) as nanometer fillers, the as-prepared PPMCB hydrogel can heal automatically in 6 h. Owing to the edge-wrapping of MXene with CMC, the disadvantage of easy oxidation of MXene is circumvented. Such excellent antioxidant properties can ensure that the hydrogel maintains more than 90% of its mechanical properties and sensing capabilities after 45 days of oxidation treatment. Moreover, the hydrogel shows strong adhesion to different materials. Based on these unique characteristics of PPMCB, flexible sensors with self-healing and long-term durability are assembled. This study provides a new strategy for preparing self-healing conductive MXene-filled hydrogels that can be applied to flexible wearable devices.