Investigation Of Needleless Thread Electrospinning Processes

With the development of nanotechnology, nanofiber material gets more attention of people. Nanofibers are characterized with large specific surface area and small aperture size thus rendering the technique a comprehensive prospect in areas like highly efficient filtering material, biomaterials, protective materials, nano sensors etc. Naturally electrospinning technique which can easily produce long nanofibers gets great promoted. However the spinneret of traditional electrospinning is using single needle nozzle. The productivity is very low and blocks the development of eletrospinning.In recent years, much attention has been paid to the development of large-scale electrospinning techniques. The strategy of improving the nanofiber production is mainly based on increasing the number of solution jets. There are three main ways:multijet in single-needle, multineedle electrospinning and needleless electrospinning. However the multineedle spinneret needs a large operating space and careful design of the relative spacing between the needles so that strong charge-repulsion between the jets and adjacent needles and the associated uneven fiber deposition can be avoided. Needleless electrospinning setups have been developed. Without using a needle nozzle, a number of jets could be generated even from a widely open liquid surface. Based on latest research a thread needleless electrospinning setup is built in this paper. The electrospinning process and electric field simulation of this new equipment are also investigated.Firstly status quo and trend of research at home and abroad in electrospinning apparatus and process is summarized in chapter1.In chapter2, study on the process of thread needleless electrospinning from both theoretical and experimental aspects. The process includes three stages:liquid entrainment, de-wetting and electrospinning. Also discuss the influence of each stage on fiber morphology.In chapter3, using orthogonal array design, the effects of thread diameter, applied voltage, spinning distance, solution concentration and speed are investigated on the diameter of PEO nanofibers made by the needleless thread electrospinning.In chapter4, using the combination of the electric field simulation and experiment, the influence on electric field distribution of the process parameters is studied. Obtain the feature of the electric field distribution of the thread electrospinning and achieve the relationship between electric field distribution and fiber diameter. It can provide a theoretical basis for the development of the thread eletrospinning.In chapter5, summarize the influence of three stages of the needleless thread electrospinning on electrospinning processes. Generalize the law of impact on jet stability and fiber apparent morphology made by process parameters and electric field distribution.Based on the research, it helps to reveal the distribution of the solution and mechanism of electrospinning on the thread. Also it has great theoretical and practical value for the improvement of the productivity of needleless electrospinning.