| Nanofibers are moving towards higher strength,lower density,smaller diameter,and more uniform distribution.Electrospinning is a simple and effective method for preparing nanofibers,and the nanofiber membranes produced by it have many special properties.,And has been widely used in important fields such as lithium battery diaphragms,biosensors,and tribo-nanometer power generation.However,due to the serious unsteady motion of the jet stream in the current electrospinning process,the electrospinning products still have the disadvantages of large average diameter and uneven distribution of the fiber membrane,which can no longer meet the needs of mass production of nanofiber membranes and high demand in some fields.The new requirements for quality fiber membranes have seriously hindered the further application and development of electrospinning fiber membranes in various fields.Therefore,in order to reduce the average diameter of nanofiber membranes,reduce the uneven distribution of fiber membranes,and improve the quality of electrospinning filaments,this paper proposes an introduction aid based on the combined simulation technology of magnetic lens technology,mathematical tools and finite element analysis.The electrospinning device of the magnetic lens,and the current commonly used excitation coil type electrospinning device as a reference,study the influence of the magnetic lens magnetic field on the unstable motion of the jet and the quality of the fiber.The main research contents are as follows:(1)Propose a new type of magnetic lens electrospinning deviceAiming at the current problems in electrospinning,this article combines the magnetic lens technology with electrospinning technology based on the electronic focusing principle of the magnetic lens,and uses the focusing effect of the magnetic lens on the electrons to control the unsteady motion of the electrospinning ribbon electric jet.In,and analyzed the relationship between unsteady motion and fiber diameter,designed and built a magnetic lens electrospinning device.(2)Using the co-simulation method to simulate and analyze the magnetic lens electrospinning deviceBecause the electrospinning process is complex and has many influencing factors,software simulation is the most commonly used method to study the electrospinning process.In order to ensure the correctness of the simulation results,this paper uses the combined simulation method of mathematical software combined with finite element analysis software.First,use Matlab software to calculate the motion trajectory of the jet in the bead model of the electrospinning jet;then calculate the simulation results of the non-uniform electric and magnetic field of the magnetic lens electrospinning in COMSOL Multiphysics,and compare the magnetic lens spinning device with The other two devices restrain the charged particle beam;finally,the simulation results of COMSOL Multiphysics are read in Matlab and the simulation trajectory of the jet flow of the magnetic lens electrospinning device is recalculated.The results show that compared with other magnetic field devices,the magnetic lens has a more obvious confinement effect on the charged particle beam,reduces the swing amplitude of the charged jet,and has a good control effect on the unsteady motion in the electrospinning process.(3)Experiment to verify the simulation resultsDesign comparative experiments on three electrospinning devices of traditional needle-plate type,excitation coil type,and magnetic lens type.Using the PAN/DMF solution with a mass fraction of 12wt% as the experimental raw material,the three devices are used to explore the non-steady state parameters of nanofiber membranes.(Fiber membrane width,jet swing angle)and key quality index parameters(average fiber membrane diameter,fiber membrane uniformity).The experimental results show that the magnetic lens electrospinning in the three devices has a better control effect on the unsteady motion of the fiber membrane,and has a better optimization effect on the key index parameters of the fiber membrane.The experimental results are consistent with the simulation results.In the experiment,the magnetic lens electrospinning is better than the excitation coil electrospinning in the improvement of the quality index.The standard deviation of the fiber membrane diameter of the magnetic lens electrospinning can be up to 55.7% lower than that of the traditional needle-plate electrospinning,on average.The fiber diameter can be reduced by up to 8.7%,so the magnetic lens electrospinning technology is an improvement and improvement to the traditional electrospinning technology. |
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