Research Of Lontronic Flexible Pressure Sensing Technology And Its Application

The flexible pressure sensors can maintain their pressure sensing ability under the condition of their own deformation,which has important application value in the fields of electronic skin,human-machine interface,and medical diagnosis and treatment.The current flexible pressure sensing mechanisms mainly include resistive,capacitive,triboelectric,piezoelectric and iontronic types.Compared with the traditional resistive,capacitive,triboelectric and piezoelectric sensors,the iontronic pressure sensing,as an emerging sensing mechanism,has the advantages of high sensitivity,high resolution,strong anti-interference ability,low measurement noise,detection of static and dynamic pressure and high linearity,and has the potential to solve the current problems of flexible pressure sensor.To this end,this thesis uses a combination of theoretical analysis and experimental research to carry out research on iontronic flexible pressure sensing technology and its application.The main research contents of the thesis are as follows:(1)Preparation technology and performance characterization of paper-based iontronic pressure sensors.Two processes for preparing iontronic pressure sensing paper have been proposed and compared,namely papermaking method and handwriting method.The iontronic pressure sensing paper can be structured into paper-based iontronic pressure sensors in the forms of two-dimensional devices or 3D tactile sensing-enabled origamis only by paper-specific manipulations of printing,cutting,folding and gluing.Notably,the paper-based iontronic pressure sensor offers a sensitivity of 10 nF/kPa/cm2,which is thousands of times higher than current capacitive sensors,a resolution of single Pa,a single-millisecond mechanical response and a high response linearity(R2>0.996).(2)Research on sensing mechanism and application of paper-based iontronic pressure sensor.Based on the classical compression theory of fiber assembly,a theoretical model of paper-based iontronic pressure sensor was established,and the model was derived and verified to reasonably explain the pressure-capacitance characteristics of paper-based iontronic pressure sensor.Furthermore,a flexible pressure sensor with excellent iontronic pressure sensing characteristics is designed.With the foldable,printable and cuttable characteristics of paper itself,the application of paper-based iontronic pressure sensors in medical wearables,human-machine interfaces and customized pressure sensing devices has been realized.(3)Research on preparation,performance characterization,and the application in electronic skin of iontronic pressure sensing rubber materialThe flexible iontronic sensing mechanism was introduced into the soft elastic silicone rubber material,and a solid iontronic pressure sensing rubber material with iontronic pressure sensing characteristics was developed.The preparation,electrical and mechanical properties of iontronic pressure sensing rubber materials were systematically studied.A single-point pressure sensor and pressure sensor array based on iontronic pressure sensing rubber were prepared,demonstrating the potential application of iontronic pressure sensing rubber in the field of electronic skin.The developed electronic skin sample has a higher spatial resolution than the human tactile sensation,has the ability to recognize the shape and size of objects,recognizes hair strands with a diameter of 80 microns,and can also recognize braille through dynamic sliding.Based on the above research content,the innovation of this thesis is an in-depth study on the working principle of iontronic flexible pressure sensing technology,and two new types of functional materials for iontronic pressure sensing,namely iontronic pressure sensing paper and iontronic pressure sensing rubber,have been proposed.With the advantages of extremely high Young's modulus and porous structure of paper fibers,paper-based iontronic pressure sensors show extremely high device sensitivity,low pressure detection threshold,fast mechanical response time and extremely high response linearity.In addition,the pressure sensing model of the paper-based iontronic pressure sensor is established,and the pressure-capacitance behavior of the sensor is derived and verified.The main innovation in the application of iontronic pressure sensing paper is to have all of the functional materials built on a single-layer planar paper substrate,from which the specific folding procedures would enable the appropriate device architecture to be constructed into a 2D or 3D format.In such implementation,we can build the entire functional devices solely relying on specific operation of paper,which is facile and inexpensive,while still maintaining high device sensitivity.Iontronic pressure sensing rubber is the first solid-state composite material for iontronic pressure sensing,which has better mechanical properties than the previous iontronic pressure sensing materials.In addition,the excellent sensing performance of the iontronic pressure sensing rubber material has also been verified and applied to electronic skin,showing excellent tactile recognition capabilities.