Acid-Hydrolysis Nanoengineering of MXene-Based Dual Cross-Linked Hydrogels for Multifunctional Applications

Overcoming the mechanical deterioration typically induced by polydopamine (PDA)-assisted dispersion of nanofillers remains a challenge in conductive hydrogels. Herein, we proposed an acid-hydrolysis nanoengineering strategy that transforms this interfacial trade-off into synergistic enhancement. First, PDA and waterborne polyurethane (WPU) are sequentially introduced to effectively inhibit MXene restacking through combined coordination and hydrogen bonding. Then, the acid-catalyzed hydrolysis step is applied to hydrolyze the amide bonds of polyacrylamide to in situ generate an acid induced network reconstruction accompanied by the formation of carboxyl/imide related functional groups and increased network densification, directly countering the mechanical compromise. Consequently, the obtained hydrogel (H-PUDMP) exhibits remarkable integrated properties: high fracture strain (1782%), enhanced fracture stress (0.43 MPa), and good conductivity (6.09 mS·cm^-1). Moreover, the hydrogel displays a segmented temperature-resistance response, enabling broad-range and self-compensating temperature sensing. Moreover, it is capable of monitoring human motion in real time as a wearable sensor. When being assembled into a TENG, it achieves an output of 210 V and a power density of 5.13 W·m^-2, demonstrating self-powering capability. Based on these superior sensing capabilities, the hydrogel is integrated into a Bluetooth-enabled smart glove, which successfully demonstrates accurate gesture recognition. Therefore, this acid-catalyzed hydrolysis strategy provides a paradigm for nanoengineering hydrogel electronics, transcending the conventional trade-offs between conductivity, mechanical strength, and functionality.