Multifunctional MXene Conductive Zwitterionic Hydrogel for Flexible Wearable Sensors and Arrays

Conductive hydrogels have good prospects in the fieldsof flexibleelectronic devices and artificial intelligence due to their biocompatibility,durability, and functional diversity. However, the process of hydrogelpolymerization is time-consuming and energy-consuming, and freezingat zero temperature is inevitable, which seriously hinders its applicationsand working life. Herein, zwitterionic conductive hydrogels with self-adhesiveand antifreeze properties were prepared in one minute by introducingtwo-dimensional (2D) MXene nanosheets into the autocatalytically enhancedsystem composed of tannic acid-modified cellulose nanofibers and zincchloride. The system has strong environmental applicability (-60to 40 degrees C), good stretchability (ductility approximate to 980%), durableadhesion (even after 30 days of exposure to air), and strong electricalconductivity (20 degrees C, 30 mS cm(-1)). By virtueof these advantages, the prepared zwitterionic hydrogels can be developedinto flexible strain sensors to monitor large human movements andsubtle physiological signals over a wide temperature range and tocapture signals from handwriting and voice recognition. In addition,multiple flexible sensors can be assembled into a three-dimensional(3D) array, which can detect the magnitude and spatial distributionof strain or force. These results demonstrate that the prepared zwitterionichydrogels have promising applications in the fields of medical monitoringand artificial intelligence.