A self-adhesive, self-healing and antibacterial hydrogel based on PVA/MXene-Ag/sucrose for fast-response, high-sensitivity and ultra-durable strain sensors

Flexible hydrogel sensors have attracted significant attention due to their broad applications in soft robots, healthcare monitoring, and electronic skins. However, the development of super-tough hydrogel-based sensors that combine self-healing, self-adhesiveness, and drift-free sensing while maintaining long-lasting stability is a critical challenge. This work presents a multifunctional hydrogel (P/M-Ag/S) composed of Ti3C2Tx MXene-Ag nanoparticles (MXene-Ag), polyvinyl alcohol (PVA), borax and sucrose. Compared to MXene hydrogels and the MXene-Ag hydrogel, P/M-Ag/S showed excellent self-adhesion (repeatable adhesion) and rapid self-healing ability (>94%) due to its increased hydrogen bond density. Additionally, the P/M-Ag/S hydrogel exhibited outstanding mechanical properties including the largest tensile strength, toughness, Young's modulus, resilience, and anti-fatigue properties, and little energy dissipation. Both MXene-Ag and sucrose endow the hydrogel with antibacterial ability with great potential as a flexible sensor even when in contact with human skin. The hydrogel strain/pressure sensor shows a high sensitivity, fast response (<28.8 ms), ultra-durability (6000 cycles), and rapid self-healing ability. It has been successfully applied for real-time human motion detection, writing encryption, and human-computer information output for amyotrophic lateral sclerosis (ALS) patients. This work demonstrates that the flexible, self-healing, super-stable conductive hydrogel has broad application prospects as a sensor in the field of national defense information encryption transmission and for portable healthcare.