Modeling And Simulation Of Nanofibers Movement In Electrospinning

Electrospinning is a novel, simple and low cost technique to fabricate nanofiber with outstanding performance, which has attracted lots of attention in the fields of flexible electron, biomedicine and MEMS. How to control the deposition of nanofibers are always the key for the applications of electrospinning, since the process of electrospun is unstable and the factors uncertainty.This paper focuses on the research of the movement and deposition of electrospinning nanofibers. The mechanics relationship between the deposited nanofiber and the moving nanofiber is discussed. A mathematical Modele is built up to simulate the process of nanofibers movement and deposition during the electrospinning.Firstly, kinematic model is built up to simulate the movement of rigidity nanofibers. Translation and rotation were included in the movement of nanofibers before rigidity nanofibers contacting the collector. Then, there was only rotation in the nanofibers after that contact the collector. So the helical whipping of jet/nanofibers formed by the combination of translation and rotation of electrospinning.The kinematic analysis of electrospinning nanofiber was done, and the influence factors of process parameters were discussed. Results show that the applied voltage and distance between spinneret and the collector are the main influencing factor in the nanofiber movement. With the distance between spinneret and collector decreasing, the projection distance of nanofiber movement diminished greatly. So the controllable deposition of nanofibers can be realized by decreasing the distance between spinneret and collector, corresponding with the principle of Near-Field Electrospinning (NFES).Kinematic model of the flexible nanofiber was built based on Maxwell viscoelastic theory, and the process of nanofiber motion and depositon was analysed. The relationship between helical whipping and electrodes distance had been discussed. Ordered nanofibers can be obtained easily when the electrodes distance was less than 3 mm, the radius of helix of nanofibers in electrospinning reduced greatly and the whipping diminished quickly. The repulsive force of charge applied on the moving nanofiber on the deposited nanofiber increases with the resistivity of collector, for less charge on the deposited nanofiber were transported through the collector. It is difficult to obtain ordered nanofiber on the collector with higher resistivity. The viscoelastic force of nanofibers increases with the concentration of polymer solution, and denser and more orderly nanofiber would be obtained. NFES experiment was done to check the kinematic model of nanofiber.Kinematic simulation of electrospinning nanofibers was done to research the process of nanofiber movement and deposition. This work has put forward the theory research and provided a good foundation for the application of NFES technique.