Experimental Study On Mass-spun Nanofibers Through Tip-Less Electrospinning

Electrospinning has been recognized as a fast, simple and low cost technique for fabricating the polymer nanofibers due to the process is a pure physical way and doesn't need template and strengthen force. With these advantages, electrospinning has attracted lots of attentions in the scientific research and industrial application. At present, in traditional single needle electrospinning, a single jet is issued from a single needle. This low throughput can't satisfy the requirement of nanofibers' applications in the fields of complex materials, bio-scaffold, wound dressings and filter membrane. The technique to mass-spun nanofibers is the key for the industrial application of electrospinning nanofibers.Based on ElectroHydroDynamics (EHD) instabilities mechanism, a novel method for the high throughput nanofibers electrospinning, which is called "Tip-Less Electrospinning (TLES)", is presented in this thesis. Instead of using the conventional needle, we use a metal cylindrical rotator as the spinneret to achieve the mass production of nanofibers under high voltage. Experimental results show that the nanofibers yield by TLES is more than 700 times enhancement than that from traditional electrospinning process, which making TLES a potential tool in producing mass-spun nanofibers for various applications.The main work in this paper are: design an equipment using for mass-spun nanofibers through Tip-less electrospinning, investigate the formation of jets on the thin liquid film and seek after the optimum parameters. This paper includes five aspects listed as follows:Bring forward a novel method for the high throughput nanofibers electrospinning based on the principle of Electrohydrodynamics.Design an equipment using for mass-spun nanofibers through Tip-less electrospinning, including a metal cylindrical rotator with smooth surface which is utilized as a spinneret, a grounded collector, a container, an insulated scraper and a high voltage supplier.Observe the formation of jets on the surface of spinneret in Tip-less electrospinning by CCD, including the taylor cone movement, diameter of Taylor cones and so on. Investigate the influence of the main parameters such as solution concentration, the spinneret type, the coated liquid film thickness, the electrode-to-substrate distance and the applied voltage on the Tip-less electrospinning by systematic experiments to get the optimum parameters.Analyze the intensity of electric field in Tip-less electrospinning process by using the ANSYS software to validate the reliability of the experiment results.