Investigation Of The Sputtering Needleless Electrospinning Processes

Nano-fibers produced by electrospinning technique 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, highly precise instrument, protective materials, nano composites etc.However, Single needle is most used in electrospinning. The throughput of single needle electrospinning (0.1-1g/h) is too low to meet the demand for industrial applications. Productivity enhancement on a comparable industrial scale is currently under active investigation, with emphasis on multi-jet electrospinning. Recently, modified single-needle, multi-needle and needleless systems have been introduced to achieve multiple polymer jets and thus improve the output of nanofibers. But, some problems occur in single- and multi-needle electrospinning, such as configuration complexity and needle clogging. Compared to modified single-needle and multi-needle setups, needleless systems have attracted more attention recently. A novel needleless electrospinning setup, the "sputtering needleless electrospinning", is developed in this paper. The electrospinning process and critical voltage theory of this new apparatus are also investigated.Firstly, status quo of research at home and abroad in electrospinning apparatus, process and theory is summarized in chapter 1.In chapter 2, the conformable solution concentration scope of polyethylene glycol oxide and polylactic acid for electrospinning is studied using single electrospinning apparatus whose process is relatively maturity. The influences of processing parameters (applied voltage, velocity of flow, gap distance) on raising spinnability of low concentration solution are studied. The influences of processing parameters (applied voltage, velocity of flow, gap distance) on reducing bead defect of PEO solution are also studied.In chapter 3, the influences of apparatus parameter (roller spinneret rotation speed), solution concentration, processing parameters (applied voltage, gap distance) on the fineness and morphology of PEO nanofibers are investigated. The performance characteristic of PEO nanofibers felt is tested using relevant instruments.In chapter 4, based on non-viscoelasticity solution critical voltage theory, considering special solution supplying method of this sputtering needleless electrospinning apparatus, adding in ellipticity parameter and solution viscoelasticity, the critical voltage theory of this new elelctrospinning apparatus is obtained through formula derivation and calculation. The correctness and applicability of this new critical voltage theory is verified through experiment.In chapter 5, the applicability of sputtering needleless electrospinning apparatus is studies for electrospining high volatile solvent soluble high polymer solution. There are some limitations for electrospinning this kind of high polymer solution using this new apparatus. The mentality of designing is proposed for improving this new electrospinning apparatus.