MXene-based High Sensitivity Pressure Sensor With Self-healing Function

The development of social intelligence is accompanied by the rise of intelligent industries such as bioelectronics,smart home,intelligent robot and human-computer interaction,which greatly stimulates the market demand for flexible pressure sensors.Flexible pressure sensors are mainly based on several types of working mechanisms,such as piezoresistive,capacitive,piezoelectric,and triboelectric.Among them,piezoresistive pressure sensor has been widely studied because of its simple working mechanism,high sensitivity,fast signal response and stable sensing performance.At present,the research on flexible pressure sensor mainly focuses on effectively improving its sensing performance（such as sensitivity,response and recovery time,minimum detection limit and cycle stability）and practical application.A large number of theories and experiments prove that the performance of sensors can be effectively improved by designing the microstructure of flexible substrates and developing the sensitive materials.However,the high-performance flexible pressure sensor still faces some problems,such as complicated manufacturing process,high-cost,poor mechanical performance,inability to heal itself after mechanical damage.In addition,there are some problems in the application research of sensors,such as the lack of integration and communication with other electronic devices（it is difficult to form a tactile feedback system）.In view of the above background,the MXene-based high-sensitivity flexible pressure sensor with self-healing function were prepared in this thesis.The specific research contents are as follows:（1）Polyurethane（PU）was cast on the surface of sandpaper templates with different surface roughness to construct a flexible substrate with micro-spinous process structure.MXene was used as sensitive material,and it was deposited on the surface of micro-spinous process of PU by spraying process to obtain the sensitive layer of MXene/PU.MXene interdigital electrodes were prepared on the surface of polyimide（PI）and membrane flexible substrate by simple spraying process.The MXene/PU/PI and MXene/PU/membrane flexible pressure sensors can be obtained after the interdigital electrode and the sensitive layer are packaged face to face.This method makes the selection of electrode substrate not limited by preparation conditions,which is universal.（2）The prepared MXene-based flexible pressure sensors show excellent sensing performance.The sensitivity of MXene/PU/PI flexible pressure sensor is as high as509.8 k Pa^-1;And the sensitivity of MX/PU/membrane flexible pressure sensor is 408.4k Pa^-1.Compared with the reported flexible pressure sensors,this sensor owns obvious advantages in sensitivity.（3）The rich hydrogen bond of PU endows the sensitive layer of the sensor with self-healing function.The cutting crack of MXene/PU sensitive layer almost disappears after self-healing for 18 h and the performance is still as high as 456.9 k Pa^-1（only decreased by 10.38%）.（4）The MXene-based flexible pressure sensor can monitor human activities and health in real time.And the 4×4 MXene-based tactile sensor array can sense the pressure distribution from irregular objects.In addition,by integrating the sensor with a manipulator,resistance-voltage converter,STM 32 single-chip microcomputer and touch electronic screen,the manipulator can realize the function of"action-perception-feedback".The device can help the manipulator grasp the target smoothly,and digitize and visualize the invisible pressure.