Highly stretchable and strain sensitive MXene/MXene:MWCNTs@TPU fiber with hierarchical conductive layers and porous elastic core structure

Fiber flexible strain sensors have the characteristics of small volume, light weight, good flexibility, easy deformation/recovery, and easy weaving. They can conform to various complex surfaces and endure various deformations, such as twisting and bending. Furthermore, the simple preparation process of fiber sensors lowers the production cost significantly. These features make them promising candidates for applications in motion monitoring, human-machine interface, and flexible intelligent products. However, the low sensitivity and narrow sensing range of existing sensors are still major challenges for their further development. To address these challenges, this paper proposes a MXene/MXene:MWCNTs@TPU fiber sensor, which adopts a two-step pre-stretching strategy to modify the porous TPU fiber surface with MXene and MWCNTs. The graded porous TPU fibers obtained by wet spinning can achieve 805% stretching, providing a reliable substrate support for the fiber sensor, the combination of multi-dimensional conductive materials and the introduction of cracks and wrinkles enhance the sensitivity 277 and sensing range 510% of the fiber sensor. The fiber sensor can detect various human motions and gestures by directly attaching to the skin or weaving into textiles, and can also be applied to information encryption transmission, demonstrating its huge potential in human health monitoring, intelligent flexible electronic products and encrypted communication.