Experiment and simulation of coiled nanofiber deposition behavior from near-field electrospinning

Both experiment and simulation works were utilized to research the deposition behavior of single coiled nanofiber on silicon substrate from Near-Field Electrospinning (NFES). In the experiment process, when the collector moving speed (CMS) is compatible with electrospinning speed, straight line nanofiber can be collected. When CMS decreases, jet would step into whipping motion due to the imbalance charge repulsive force from landed nanofiber. As decreasing CMS, nanofiber in waved shape, single circle coil and multi-circle coil can be fabricated in turn. In order to improve the controlling technology, a computational model based on Maxwell viscoelastic theory was build up to analyzed the deposition behavior of single nanofiber. Simulation results show that CMS is the main controlling parameter influence the nanofiber deposition morphology: beads deposited in straight line, when CMS higher than 0.35m/s; beads deposited in waved shape, when CMS lies between 0.15m/s and 0.35m/s; beads in single-circle coiled can be gained, when CMS ranges from 0.08m/s to 0.15m/s; beads would deposit in multi-circle coil, when CMS lower than 0.08m/s. The effect of collector conductivity was also investigated by the computational modeling: the diameter of multi-circle nanofiber zone and distance between adjacent nanofiber coil increases with collector conductivity decrease. The calculated behaviors of nanofiber deposition are in good agreement with the experimental results, which is a good way to represent the motion behavior of charged jet and nanofiber.