Preparation Of Wearable Flexible Sensor Based On MXene/TPU Composite Film And Performance Study

Flexible sensors have received wide attention in the field of transient electronic skin,intelligent robotics and human-computer interaction technology due to their good portability,high flexibility and excellent sensing performance.Flexible sensors have flexible characteristics than traditional metal or semiconductor sensors,cause it is more suitable for signal acquisition in implantable and wearable devices.Two-dimensional metal-carbon nitrides MXenes have very excellent electrical properties and strong surface activity and are commonly used as active materials for sensors.However,the poor stability of MXene when exposed to aqueous oxygen and its poor ability to interact with the polymer matrix become important factors limiting its practical application.In this research highly conductive Ti₃C₂MXene/TPU sensing elements with pleated structure and stretchable Ti₃C₂MXene/TPU sensing elements were prepared by a simple coating process using thermoplastic polyurethane(TPU)as the substrate.Based on these sensing elements,pressure sensors and strain sensors were prepared by structural design,respectively.The effects of distribution density and pleat structure on the sensor performance and the specific performance of the sensor for signal acquisition in practical applications were investigated.The main research contents and conclusions are as follows.The Ti₃C₂MXene/TPU composite films with different distribution densities were prepared by multiple coating methods,and the composite films were encapsulated with polydimethylsiloxane(PDMS)to obtain flexible strain sensors with excellent performance in PDMS-MXene/TPU construction.The microstructure and morphology analysis of the composite film as well as the sensing performance and mechanical property testing of the sensor were carried out,and the specific performance of the sensor in practical applications was explored.The experimental results showed that the best MXene distribution of the composite film was achieved when sprayed three times,and the microchip size diameter was 1?m.It was demonstrated that the PDMS package could significantly improve the stability of the sensor.This strain sensor has low detection limit(less than 0.005%,0.5?m),wide sensing range(0-90%),short response time(120.1 ms),and good durability(>3000cycles),as well as good performance in practical applications.A Ti₃C₂MXene/TPU composite film with a pleated structure was prepared by the pre-stretch-and-release method,and the structural design of a flexible pressure sensor was carried out on the basis of this composite film,and then a flexible pressure sensor was prepared.The performance of the sensor,such as sensitivity and response time,was also tested to explore the signal feedback for practical applications such as joint activity,pulse beat,sound detection,etc.The experimental results show that the best sensing performance of the composite film prepared at45%pre-stretching and the microchip size diameter is 1?m.It is proved that the presence of the pleated structure can make the sensor sensitivity improved,and this MXene composite sensor with pleated structure has a wide pressure range(400Pa-74.8 k Pa),short response time(110 ms)fast recovery time(90 ms)characteristics and good cycling stability(>3000 cycles).