MXene/silk fibroin strengthened PVA-based eutectogel with excellent self-healing ability and environmental adaptability: Design, synthesis, and sensing application.

In order to solve typical problems of instability in a variety of environments, lack of self-healing ability and poor mechanical properties of traditional hydrogel materials, herein, a superelastic self-healing eutectogel of DPMS was designed and prepared in a deep eutectic solvent (DES) system using poly(vinyl alcohol) (PVA) as the bulk skeleton material, while two-dimensional MXene (Ti3C2TX) nanosheets and silk fibroin (SF) as reinforcing fillers. As a result, the prepared DPMS eutectogel possesses a high tensile strength of 7.63 MPa, while its elongation at break can reach 1115.2%, higher than most reported polymer hydrogels (<1000%). Moreover, this eutectogel shows excellent self-healing ability and can achieve rapid self-healing within 10 min, and its tensile strength and elongation at break can restore to 84.7% and 97.4% of the initial levels. More importantly, the eutectogel can withstand various environmental conditions, such as atmospheric or even vacuum evaporation and low-temperature freezing, while maintaining good mechanical and sensing performances. In addition, the eutectogel-assembled sensor has a high ionic conductivity of 0.61 S/m and a high strain sensitivity of 5.17 kPa-1. Besides, a stable electrical signal can be transmitted after 200 cycles at 30% strain.