Flexible Self-Powered Tactile Sensor Based On MXene Hybrid Spinning

In recent years,owing to the rapid development in the field of wearable electronics,there has been an increasing demand for flexible tactile sensor arrays with good wearing comfort and breathability.At the same time,due to the demand of battery life,safety risks and wearable comfort,scientists have been pursuing to make wearable devices take energy from human movement and physiological activities to achieve self-powered.Tactile sensors based on the friction initiation effect can directly convert mechanical energy into electrical energy.It has the feature of low power consumption and is the effective ways to realize the self-powered of sensing system.In addition,it also has the advantages of simple structure,low cost,light weight and abundant material selection,which is one of the current research hotspots for wearable sensors.Meanwhile,nanofiber films have important research and application value in the wearable field due to the benefits of good breathability,comfortable and simple preparation process.Therefore,based on the advantages of friction-initiated sensors and nanofiber films,a flexible self-powered tactile sensor based on MXene hybrid spinning have been designed and prepared in this project.The details are as follows:(1)The MXene powers with multilayers structure and-F groups have been successfully prepared by in situ etching method.Subsequently,the MXene powder has been added to the PVDF solution to obtain the PVDF/MXene solution.Then,a large-area(20×50 cm~2)PVDF/MXene nanofiber films are prepared by solution blow-spinning(SBS)technology.The nanofiber films have the structure of 3D network and good breathability.And the MXene has been successfully spun into the PVDF film with uniform distribution on the surface.A triboelectric nanogenerator(TENG)self-powered tactile sensor has been further prepared by using this film as the critical structure.(2)In this section,the properties of the prepared flexible self-powered tactile sensors are characterized and modulated.First,the self-powered tactile sensor obtained by SBS technology has excellent basic wearable properties such as flexible,hydrophobic,breathable,washable,and tailorable.Secondly,the electrical output performance is proportional to the area of the device.when the self-powered tactile sensor based on PVDF/MXene hybrid spinning is mixed at15%concentration,it has a maximum output voltage of 108 V and a sensitivity of 12.33 V/k Pa.The response time and recovery time are 80 ms and 70 ms,respectively.There is no significant degradation in performance for 16,000cycles with good durability.(3)Its application to energy harvesting,health monitoring,and array sensing has been investigated.When used as an energy harvestor,it has an output power density of 12.6 m W/m~2at an external load resistance of 500 MΩ,demonstrating the self-powered potential of the sensor.When combined with the human body as a biomechanical energy harvestor,it can charge commercial capacitors and continuously drive low power electronics and 74 LEDs.For health monitoring,the voltage response of fingers,wrists,and knee flexion can be monitored.It can also be designed as 3×3 and 5×5 array for pressure mapping and slide path recognition.Thus,this tactile sensor shows promising applications in wearable devices,soft robots and human-machine interaction.