Research On Electrospinning Process Behavior And Vibration-Electrospinning Technology

Electrospinning technology has obtained word-wide attention for its convenience in producing nanofibers. Electrospinning is a technology using electric force supplied by a high voltage field to eject Taylor Cone into jets which are finally dried and solidified into nano-scale fibers as solvents vaporized. Mathematical model is a key point for development of electrospinning technology. Though much research has been conducted experimentally and theoretically, its mathematical model is far from perfect possibly due to the complex and nonlinear phenomena and quantum-like properties involved in the proposes, and many factors affecting the procedure such as solutions or melts' viscosity, molecular weight, entanglement of the macromolecule, applied voltage, flow rate and ambience. Based on known models (e.g. Spivak-Dzenis model), a more complete mathematical model is established considering more effects on the procedure, which has wide applications. Its reduced one-dimensional model is of utter simplicity, and has many practical applications.Diameter is a key parameter of electrospun nanofiber, which determines whether the obtained fiber could have magic nano-effect properties. Much attention was paid on the prediction. of diameter of electrospun nanofiber. Spivak suggested a ubiquitous scaling law between the jet diameter and its running distance which was widely used. Through analysis of different stages in the procedure of electrospinning, we find the scaling law is valid only for a special stage. Based on our established mathematical model, we obtain different scaling laws for different stages in the procedure. Also we obtain various scaling laws which can not be obtained by other models, such as the relationships between voltage and solution flow rate, diameter of the obtained fiber and voltage, current and voltage, diameter and flow rate, and others. All these scalings are experimentally verified and have many potential applications in experiment.Experiments and theoretical analysis reveal that polymer solution Can not be electrospun into nanofibers when the Solution viscosity surpasses a certain threshold. We designed a new set of electrospinning set-up coupled with ultrasonic equipment. Some experiments were carried with the new set-up and experimental results showed that our novel vibration-electrospinning apparatus can produce nanofibers from those solutions with high viscosity or coagulated which can not be ecletrospun by classical electrospinning processes; and also the apparatus leads to much finer nanofibers than those obtained without vibration. Furthermore, eletrospinning of original carbon nanotubes added in polymer solution shows that our vibration-electrospinning apparatus works well on additives enhanced nanofibers with good dispersion and alignment.