Study On Taylor Cone Morphology And Jet Mode Characteristics In Electrospray Printing Process

As an electrohydrodynamics-based microdroplet jet forming technology,electric field-driven jet deposition printing can achieve sub-microscale high-resolution fabrication with the advantages of high flexibility,large-area printing,and good material compatibility,which has broad application prospects in the fields of nano-3D printing,bio-printing and integrated circuit preparation.Taylor cone,as a precursor process to electric field-driven jet deposition printing,is the fundamental process for generating submicron droplets.There are many factors affecting the Taylor cone,including fluid properties,electric field characteristics,etc.,but there is no high conformational relationship that can reveal the conformational relationship of the above influences on the formation,evolution,spray pattern,and finally on the quality of the generated submicron droplets.To address the above issues,this paper discusses the connection between Taylor cone,electroblowing and spray pattern through theory,simulation and experiment,and investigates the effects of different parameters and materials on Taylor cone morphology and spray pattern in the electroblowing process.The main contents and research results of this paper are as follows:(1)Firstly,a mathematical model for the evolution of Taylor cone by electric fielddriven jet deposition is established,and the multi-physical field coupling process of this technology is analyzed in detail.The multi-physics field coupling model is created using the electrostatic field module,two-phase flow module and partial differential equation module,and the construction of the electric field-driven jet deposition printing simulation model is completed.The simulation model can use the simulation results of electric field strength,charge density,and volume fraction to better explain the simulation and experimental phenomena,and deepen the understanding of electric fielddriven jet deposition printing.(2)The simulation of the electric field-driven jet deposition printing process was carried out to describe the morphology of the Taylor cone by defining the cone length and cone angle,and the effects of voltage,nozzle-substrate distance,and ink velocity on the morphology and spray pattern of the Taylor cone were discussed separately.The results reveal the effects of each operating parameter on the electric field flow field and on the Taylor cone morphology and spray pattern;the phase diagrams of voltage and nozzle-to-base distance as well as voltage and ink velocity are also constructed to provide guidance for experimental improvement.(3)An electro-jet printing experimental system was built to meet the experimental requirements,which can realize the in-situ observation experiments of droplet injection,Taylor cone morphology regulation,and jet pattern regulation.The experimental study of the effects of each parameter on the Taylor cone morphology and injection pattern was carried out,and the experimental results had the same regularity as the simulation results,which confirmed the authenticity and feasibility of the simulation results.(4)Finally,a multi-field coupled simulation model is used to simulate and discuss the effects of different material physical parameters on the spraying process,Taylor cone morphology and spraying pattern.This study reveals the characteristics of the Taylor cone morphology and jetting pattern of the electrojet printing process,which provides guidance for fine-tuning the nanometer(submicron)droplet dynamics behavior of nano-3D printing jets.