Research On Underwater Strain Sensor Based On Mxene/Regenerated Fiber And Its Performance

Flexible wearable strain sensor is one of the important applications of wearable electronic products.Its output signal is variable.It is a device that converts physical deformation into electrical signal.At present,based on its unique electrical characteristics,strain sensors have been widely explored in a variety of scenarios,such as disease diagnosis,patient monitoring and human exercise physiology detection.Among them,due to the important role of marine exploration in economic development,human security,disaster prevention and military defense,researchers have developed a large number of technologies to monitor the marine environment by developing various underwater sensors.The water resistance of underwater sensor is an important parameter to ensure its working stability and service life.Therefore,it is very important to develop resistance strain sensors that can work stably in high humidity environment or water.The traditional underwater strain sensor usually adopts waterproof or hydrophobic treatment.However,in practical application,repeated deformation will weaken the interface bonding and damage the waterproof or hydrophobic layer,which will greatly affect the sensitivity and stability of the strain sensor.In this work,a fiber like flexible strain sensor with core-shell structure was prepared by coaxial wet spinning technology.The preparation process of coaxial MXene/cuprammonium fiber（MCR）strain sensor prepared by Ti₃C₂T_xMXene conductive ink and cuprammonium spinning solution was explored and optimized.The core conductive layer of coaxial MCR is MXene conductive ink,and the shell is cuprammonium fiber.The rich NH₄⁺between Ti₃C₂T_xnanosheets and the hydrogen bond between cuprammonium fiber and Ti₃C₂T_xsurface end group form a solid two-phase interface and core-shell structure.Based on this,the coaxial MCR underwater strain sensor has a stable response to the monitoring of human underwater motion（knee joint,elbow joint and finger joint）,and its sensing performance is still stable under 5000 tensile cycles,with high conductivity in dry state.In addition,we found that the special core-shell structure realizes the selective strain sensing effect under dry and wet state transition.It is worth noting that when one-dimensional coaxial MCR is integrated into the fabric through weaving technology,the coaxial MCR fabric strain sensor still has stable conductivity and underwater sensing effect.This provides the possibility for mass production of fabric based coaxial MCR strain sensor,and opens up a new direction for the design of flexible underwater strain sensor and intelligent integrated device.