MXene-composited and B–N coordination mediated organohydrogels with robust elasticity and environment tolerance for flexible sensors

Abstract

Conductive gels have shown vast potential as flexible sensors for applications in health monitoring, soft robots, and human-machine interfaces. Nevertheless, there remains a significant challenge to integrate low hysteresis, environmental tolerance, and high sensitivity in one component for accurate and stable signal outputs. In this work, a conductive organohydrogel is prepared by the radical polymerization of 3-acrylamidophenylboronic acid (APBA) and acrylamide (AM) in the presence of MXene followed by solvent-replacement strategy. The organohydrogel exhibits high stretchability (>900%), robust elasticity (residual strain <12%), superior environmental tolerance (-60 to 60 °C), and long-term stability in an open environment (>60 days) owing to the presence of B-N coordination and multiple hydrogen-bonding interactions within the gel network. As a flexible sensor, it can precisely distinguish successive tiny (1%) and large tensile strains (700%) even stored at -20 °C for 7 days, and output reliable electrical signals of electrocardiograms and electromyograms with neglectable attenuation when exposed at the ambient environment for one week. Moreover, the organohydrogel shows remarkable temperature sensitivity with temperature coefficient of resistance of -2.71% °C^-¹, and can accurately differentiate the temperatures of different human body parts with tiny differences for health monitoring. Our work may give a solution to design reliable gel-based flexible sensors for various applications.