A hydrogen-bond armored MXene hydrogel for oxidation-resistant, dual-mode wearable sensors

Abstract

Wearable MXene-based hydrogels hold significant promise for flexible electronics due to their tissue-compliant mechanics and exceptional electrical properties, yet their practical deployment is fundamentally challenged by MXene's rapid oxidation in aqueous environments. To address this limitation, we developed an oxidation-resistant nanocomposite hydrogel through multi-hydrogen-bond reinforcement using poly(N-acryloyl glycinamide) (PNAGA), cellulose nanocrystals (CNC), and MXene. In this design, hydroxyl groups on CNC form robust hydrogen bonds simultaneously with the PNAGA network and MXene surface functional groups, establishing a ternary protective barrier that sterically isolates MXene from water/oxygen exposure while enhancing nanosheet dispersion and mechanical reinforcement. The resulting PNAGA–CNC–MXene (NCM) hydrogel achieves a high electrical conductivity of 0.59 S m⁻¹ alongside superior mechanical properties. As an integrated sensor, it exhibits dual functionality: strain sensing with a gauge factor of 2.91 and 260 ms response speed, coupled with temperature detection at high sensitivity (−2.16%/°C) and 0.1 °C resolution. Critically, Bluetooth-enabled wireless transmission facilitates real-time monitoring of physiological signals on mobile devices. This hydrogen-bond network strategy not only resolves MXene's oxidation-stability conflict but also advances NCM hydrogels as versatile platforms for next-generation wearable electronics, personalized health monitoring, and human–machine interfaces.