Research On Design And Application Of Flexible E-skin Based On Nanofiber Structure

Electronic skin is a flexible electronic device that simulates human skin to perceive external stimuli and has excellent application prospects in health detection,medical diagnosis,human-computer interaction,intelligent prosthesis,and robotics.Compared with photolithography and 3D printing,which prepare micro-nano structures with high cost,complex processes and expensive equipment,nanofiber preparation based on electrospinning technology has significant advantages such as simple process,low cost,unique three-dimensional multilayer structure,and large-scale preparation,which has attracted wide attention from researchers and provided a new solution for the development of flexible electronic skin.The main content of this dissertation is based on the study of pressure sensing in electronic skin,using electrospinning preparation of nanofibers as a technical route.Two flexible pressure sensor devices were designed,and the preparation,sensing performance and application of the devices were studied.The dissertation includes the following three parts:（1）A multilayer wearable flexible pressure sensor based on electrospinning nanofibers with resistance gradients was designed with excellent breathability,biocompatibility,and biodegradability.Benefiting from the multilayer modulation of the sensor,a high constant sensitivity of 33.955 kPa^-1 was achieved over a wide pressure range of 0-80 kPa.In addition,the prepared flexible sensor possesses excellent sensing properties such as fast response recovery time,good vertical pressure,and bending stability.（2）A multi-functional flexible pressure sensor was designed based on electrospinning ion-capacitance-triboelectric type nanofibers that mimic the human skin.The prepared ion pressure sensor has high sensitivity,low detection limit,fast response-recovery time,and excellent stability.Secondly,the output voltage of the triboelectric nanogenerator for different materials and the actual sensing performance were investigated.（3）Based on the above two prepared flexible pressure sensors,corresponding application studies were carried out respectively.The prepared multilayer wearable flexible pressure sensor achieves high sensitivity detection of important physiological signals of the human body,while an integrated sensor array system that can locate the position of objects is constructed and applied to simulated sitting health monitoring.The prepared ion-capacitance-triboelectric multifunctional flexible pressure sensor was investigated for its dynamic and static sensing capability to external pressure stimuli.First,a 2×3 ion-pressure sensing array was designed to implement a music player system as well as an intelligent handwriting recognition system for different phrases using the contact initiation principle of frictional electricity.Finally,a real-time recognition system for object material and shape is implemented by combining an ion-capacitance sensing array and a frictional pressure sensor.In summary,this dissertation prepares two high-performance flexible pressure sensors based on electrostatic spinning nanofibers with excellent sensing performance in sensitivity,response-recovery speed,and stability,realizing the application of flexible pressure sensors in detecting important physiological signals in the human body and human-machine interaction.