Multifunctional flexible MXene/TA@CNC electronic hydrogel patch with robust adhesion and self-healing properties for wearable electronics

Conductive hydrogels have been extensively investigated and demonstrate promising applications in wearable and flexible sensors. However, their broader implementation in this field is hindered by the insufficient strain sensitivity, susceptibility to mechanical damage with limited self-recovery, and inadequate adhesion to human skin. Herein, we present a multifunctional MXene/TA@CNC electronic hydrogel patch (MTC e-patch) by integrating highly conductive two-dimensional (2D) transition metal carbides (MXene) and tannic acid-coated carboxylated cellulose nanocrystals (TA@CNC) with polyvinyl alcohol and borax. And dynamic three-dimensional (3D) network is formed through synergistic dynamic hydrogen bonding and dynamic borate ester linkages. The incorporation of TA@CNC effectively prevents the oxidation of MXene, thereby extending the operational lifespan of hydrogels. The flexible covalent crosslinked network, combined with the rigidity of TA@CNC, imparts the MTC e-patch with excellent electrical conductivity (1.62 S/m), superior mechanical strength (≈1.35 MPa, 930 %), robust adhesiveness (≈28 kPa), and high self-healing capability (92 %). The rapid (161 ms) and sensitive (Gauge factor = 4.39) sensing performance of the developed wearable sensor enables the precise detection of subtle human motions, such as swallowing, throat vibrations during speech, and pen strokes during writing. Even when damaged, the sensor continues to provide stable signal output, demonstrating significant potential for applications in smart wearables, electronic skins, and human–machine interfaces.