Chitosan/acrylamide/MXene hydrogel sensor with high mechanical properties, long-term sensing stability, rapid gelation via Fe2.

Owing to low biotoxicity, excellent stretchability, and good adhesion properties, hydrogel sensors have received extensive attention from the academic community and developed rapidly. Many scholars have made a series of efforts to explore suitable rapid gelation schemes, which have greatly expanded the development space of hydrogel sensors, but the existing rapid gelation schemes are inevitably cumbersome or costly while achieving rapid gelation. In this work, a simple and inexpensive controlled rapid gelation scheme was found, which only requires the addition of a thermal initiator and ammonium ferrous sulphate into the gel system to enable the controlled rapid formation of chitosan/acrylamide hydrogels at room temperature. In this study, while achieving rapid gelation (within 12 s), the physical properties as well as the sensing properties of the hydrogels were improved by adding Al3+ and MXene. The final composites obtained have good physical properties (stress 500 kPa, strain 2640 %), excellent sensitivity (GF = 4.48, deformation of 200-500 %), and adhesion properties to a wide range of materials. The chitosan/acrylamide/MXene sensors prepared by this protocol have the effect of detecting different movements of the human body, including repetitive or fine movement changes.