Design And Implementation Of Flexible Sensor For Electrohydrodynamic Inkjet Printing

Electrohydrodynamic(EHD)inkjet 3D printing technology has significant technical advantages in the field of flexible electronic manufacturing because of its advantages of small and micro printing configuration,high resolution and wide application of printing materials.Flexible sensors manufactured by EHD have broad application prospects in wearable devices,environmental monitoring and other fields.This paper uses EHD technology to design and prepare three types of sensors with different functions and typical multifunctional integrated sensors.The main research work is as follows:(1)Through the experimental study of EHD inkjet printing process parameters optimization,the optimization and adjustment tests were carried out on the key process parameters such as bias voltage,amplitude voltage,pulse frequency,distance from nozzle to substrate,duty ratio and table moving speed.The feasible and stable process path of AgNPs(silver nanoparticles)inks in electro-printing equipment was established.The "Taylor cone pattern",obtained by adjusting and controlling is the ideal construction mode of EHD printing.The influence mechanism of process elements on the forming quality and precision of print pattern is explored,which lays a key technological foundation for the subsequent sensor design and preparation in this work.(2)The flexible pressure sensor based on AgNPs sensing material,PET flexible substrate and PDMS was fabricated by EHD inkjet printing technology.After the optimization of the process,the line width of AgNPs printing pattern was about 50μm.Through theoretical calculation,simulation and experiment test,the sensitivity difference of different sensing structures and the reasons are analyzed.The multi-layer stacking design can significantly improve the sensitivity of the integral thin-film sensor without increasing the spread area of flexible devices.Based on the seepage theory and tunnel effect,the sensing principle of the device is explained,and the application of tactile perception is explored.(3)According to the principle of microwave scattering in wireless passive technology,a flexible microwave sensor made of AgNPs material was fabricated by using EHD technology,and the optimal size parameters of the sensor SRR(open resonant ring)structure were designed.By comparing the parameters of different structures through calculation and testing,it is found that SR3(open tricyclic helix structure)has the best structural results.The application exploration is carried out in aging performance test at high temperature and bending performance tests.(4)The flexible gas sensor was obtained by deposition of SnO2,Pd/SnO2,CNT/SnO2 gas-sensitive films on PET substrate by EHD inkjet printing technology,and the performance of Pd/SnO2 was determined to be the best.The results show that Pd/SnO2 layer has a large fold layer under the microstructure,which increases the specific surface area and accelerates the oxygen adsorption efficiency.A flexible microwave gas sensor with an SR3 structure was fabricated using Pd/SnO2 gas-sensitive material,and wireless passive monitoring of H2 concentration was realized by analyzing signal migration.(5)Based on the aforementioned research,an integrated flexible sensor with multifunction integration of temperature,humidity and pressure was designed and prepared by using EHD inkjet printing technology.Through performance testing and application scenario verification,the measurement capability of this kind of integrated sensor was explored.Each sensor unit did not interference with each other and the signal was good.This research has made a little contribution to the development of flexible electronic manufacturing field.The prepared flexible sensor has good sensing performance,and can be further expanded application scenarios through the multifunctional integrated design.