Producing Nanofiber By Flat Spinneret Equipment In Electrospinning

As nanofibers have several special properties like high surface area to the volume ratio and special surface or interfacial effect, they can be used in many fields such as filter membrane, life science, protective clothing and nano-sensors. Electrospinning have large advantage of other nanofiber producing methods for simple operation and producing in succession. In electrospinning process, when subjected to strong electric field,positive and negative charges in polymer solution are seperated by electrode,the seperated charges are pulled by the electricfield strength which form a jet,the jet undergoes electric field strength, repulsive force between likecharges,curve restoring force and so on which result in whipping.After evaporation of the solvent,nanofiber will deposit on the collector.The greatest defect of electrospinning is low production,the complex interference of jets retard mass production. In this paper, we use the methods of experiment and electricfield simulation to study the effect of electric field distribution on electrospinning.Find that plate style equipment is a feasible method for mass production.We design two electrospinning equipments which have different electricfield distribution,one is conventional needle equipment and another is auxiliary-plate needle quipment.In chapter two,one needle is used to produce nanofiber in the two equipments with PEO/water solution under different parameters including spinning voltage,spinning distance and flow rate.The result show that uniform electricfield have a good effect on electrospinning.In charpter three, a modified numerical model which is based on existing model is built to simulate the process of electrospinng and forcast the diameter. In the fourth and fifth chapters,three needles are used in the two electrospinning equipments,by searching the fiber's diameter and morphology of the fibrofelt,we have the conclusion that auxiliary plate-needles equipment can decrease the interfere effect among three jets and make the fibers easy to collected.Charpter six base on auxiliary plate-three needles equipment,study the distance which from needlepoint to auxiliaryplate(DNA) effect on electrospinning,find that shorter DNA have a better fiber.In the last part,To implement the needleless electrospinning,we use shortening progressively needles for electrospinning.Find that the shorter the needle used,the less interference among the jets,but need a larger applied voltage for electrospinning,meanwhile, analysis the reason by means of the electricfield simulation.