Experimental And Theoretical Study On Electrospinning Multi - Jet Technology Of Needle - Type Auxiliary Electrode

Recently, electrospinning has being one of most studied and most widely used tachnology in field of the preparation and application of nanofibers over recent decades.The main idea of electrospinning is to produce dose a polymeric solution through a charged needle. Droplet of solution at the needle orifice, called Taylor cone, will form jet or viscous fuild, which will become nanofibes with a range diameter of tens to hundreds nanometers. The best way to increase the production efficiency is to generate multi-jets, which also has attracted great attention both at home and abroad now.As to traditional electrospinning systems, the production efficiency is too low, which limits the commericaliza of nanofibers. Needleless electrospinning techniques have a high potential for industry. However, some technological peoblem have been identified as barriers to widespread use, including high voltage power supplies and rapid solvent evaporation, as well as high casts. But, the multi-jet electrospinning via auxiliary electrode can avoid those problems.Firstly, this paper researched the influence of experiment parameters of the auxiliary electrospinning on the multi-jet, such as the position (parallel/perpendicular/ ralative to spinning nozzle), the number and the charge (possition/nagetive/zero). Especially it explored the critical condition in different position.And then, in order to under the theory of multi-jet electrospinning via auxiliary electrode, dispersion relation was used to model building of multi-jet electrospinning. This study obtained the mathematical model and thoroughly investigated the critical condition of generation of multi-jet. At the last, with the purpose of researching the mechanism of the influence of auxiliary electrode on multi-jets, the software, COMSOL 4.2, analyzing the the effect of field distribution, was used.It showed that using the auxiliary electrode can lead to the generation of multi-jet no matter where it is(parallel/perpendicular/ralative to spinning nozzle). The closer distance between auxiliary electrode and cappllary, the more multi-jets there are. when the auxiliary electrode linked to negative voltage, the potential difference between auxiliary electrode and cappllary would be higher, the more multi-jet would be. While, the auxiliary electrode linked to positive voltage, there would be only one jet. Double auxiliary electrode has the same impacts on multi-jet as single. What’s more, the number of multi-jet would be more with the help of double auxiliary electrde than single at the same experiment condition. Theoretical research shows that the closer distance between auxiliary electrode and cappllary, the stronger electric field force would be, producing a stronger electric field, which made the generation of multi-jet more easier. And, the electrospinning via the auxiliary electrode can reduce the critical voltage, so it may save energy.This study has great significance for the in-depth knowledge of electrospinning, especially understanding the theory of the generattion of multi-jets causing by small Taylor cones in the electrostatic field. This research achievement possesses also has important reference value of improvement and design of new type of electrospinning equipment.