Design And Research Of Iontronic Pressure Sensor With Linear Response And High Sensibility

With advances in 5G communications and AI&Internet of Things,flexible pressure sensors are rapidly evolving as the basis for human-machine interface.Capacitive sensor is popular because of its low power consumption and fast response.However,its limited electrode distance prevents further improvement of sensitivity.In recent years,a new sensing mechanism based on double layer capacitance is proposed,which is called iontronic sensing.Due to the supercapacitor characteristics of electric double layer（EDL）capacitors,iontronic sensors usually have higher sensitivity and signal-to-noise ratio than traditional capacitive sensors.In order to improve the sensitivity and response linearity of the flexible pressure sensor,this subject carries out theoretical analysis and experimental research respectively from two aspects of the micro-structure optimization of the sensor and the material optimization suitable for the iontronic sensor.The main research contents are as follows:（1）The correlation mechanism between the finite element simulation and the sensor sensitivity curve is established.The design and simulation proved that the Hill structure with high sensitivity and the Ridge structure with high linearity,and further we proposed the design concept of the hummock-ridge structure,which provides theoretical support for the design of sensors with both high sensitivity in low-pressure and linear response in high-pressure.（2）Polyvinyl alcohol/phosphoric acid（PVA/H₃PO₄）gel was used to flip the pre-stretching PDMS mold to prepare the Hill-Ridge-structure electrolyte film,which was assembled into a pressure sensor with Ag NWs flexible electrode.The measured sensor sensitivity curve shows the characteristics of high sensitivity and piecewise linear response,which is consistent with the finite element simulation results.The Hill-Ridge structure sensor has excellent performance such as ultra-low pressure detection limit（0.32 Pa）and fast response,and has a wide application prospect in physiological signal monitoring,handwritten letter recognition,array recognition and other scenarios.（3）By regulating the mechanical,electrical and water-retaining properties of traditional hydrogels,CO₂LFe^III coordination enhanced P（AM-co-AA）/EG/Li Cl double network organogel film was prepared and iontronic pressure sensor was further fabricated.Compare with PVA/H₃PO₄,it is non-corrosive and the dynamic response of the preparation sensor is not affected by the frequency.The new gel material broadened the material selection of electrolyte film for iontronic sensor.The innovation of this paper is that the working principle of iontronic flexible pressure sensor is deeply studied,and the correlation mechanism between the finite element simulation and the sensor sensitivity curve is established,which provides theoretical guidance for the performance control of iontronic sensor.The contradiction between the sensitivity and linearity of the sensor is coordinated in a piecewise linear way,and the widely studied hydrogel material is used as the ion layer,which provides a new way of thinking for the structural design and material selection of iontronic sensor.