Research On Printing And Sintering Technology Of Nano-Silver Electrode Based On Electrically-Driven Near-Field Direct-Writing

In recent years,the advance of cutting-edge technologies such as Artificial Intelligence,5G networks,and Big Data has driven the rapid development of structural health monitoring.In the structural health monitoring network system,as the hardware basis for data collection,analysis and transmission,various specific functional forms of intelligent materials and structures such as sensors,actuators,and energy harvests are particularly important.Meanwhile the invention and development of electricallydriven near-field direct-writing technology has provided a new road for the design and fabrication of flexible sensors.Electrode is the indispensable component of the most sensors,so the research of printing and sintering technology with nano-silver ink,based on electrically-driven near-field direct-writing technology and its application in allprinted flexible sensors has important theoretical significance and prospect of application.The content of this thesis is the fabrication of electrode based on the electricallydriven near-field direct-writing printing technology,using nano-silver ink as the printing material.In terms of systematic and in-depth research of printing theory,numerical simulation and experiment research,the main contents are as follows:(1)Build the experiment system of electrically-driven near-field direct-writing printing technology,introducing the system structure of the printing technology,and analyzing its printing principle.Theoretically,the generation of Taylor cone and cone jet during the direct-writing process is analyzed,and mathematical model of load analysis is established of Taylor cone in electric field.Also,the printing modes are classified and compared,and finally screen out the main process parameters and fluid parameters that affect printing accuracy and control.(2)Analyze the printing theory of electro-hydrodynamics in the electricallydriven near-field direct-writing technology,inferring the governing equations of the electric field and the flow field,and establish the coupling mathematical model between the electric field,the flow field and the charge density field.The mathematical model inferred lays a theoretical foundation for numerical simulation and experimental research of the next.(3)Numerically simulate the electric field and intensity of the field under different parameters.Simulating the effects of printing voltage,needle size,spacing between the needle and plate and other parameters on the electric field.Combined with specific experiments to optimize process parameters of the electrode printing,and create a process window of printing.(4)Experimentally study the influence of the parameters of sintering process including sintering temperature and time on the microstructure and electrical properties of electrode film printed by the nano-silver ink,optimizing the sintering process parameters and analyzing the sintering mechanism of the printed electrode.In addition to the sintering mechanism,experimentally study other mechanism that can effectively improve the electrical performance of the electrode.The experiment results indicate that by doping appropriate amount(0.2%-0.5%)of carbon nanotubes in the nano-silver conductive ink,the electrical properties of the electrode film after printing and sintering can be further improved,and the effect and mechanism of doping on its microstructure were studied.Explore the problem of combination of printed electrodes and other components of all-printed flexible sensors,new printing technology such as AC printing method,and process development of the new nano-silver conductive ink,which can provide a reference for the next research of this subject.