Modified electric fields to control the direction of electrospinning jets

Abstract

Electrospinning is a well known process for fabricating sub-micron size fibers. A high voltage potential is used in electrospinning to launch a polymer jet from a droplet of polymer solution towards a grounded collector. Most of the electrospun fibers collect on the grounded collector, but depending on the design of the electrospinning apparatus and the environment, some of the fibers drift away from the collector and are captured on other objects.In this work we apply the hypothesis that the electrospinning jet follows the path of the electric field's current density lines. By controlling the direction of the current density lines one can control the path of the electrospinning jet and hence can control the location of where the fibers are collected.The current density lines are determined by the gradient of the static electric potential field. The electric field is modified in this work by positioning charged electrodes that change the potential field and hence change the potential gradient and the path of the current density lines. In this way, the jet, following the current density lines, can be directed towards desired locations and away from undesired locations. The static electric field was modeled by numerically solving Laplace's equation for the potential field. Electrospinning experiments were conducted with the same geometric arrangement of electrodes for comparison. The results show the center of mass of the electrospinning jets generally followed the current density lines. This work shows it is possible to direct the electrospinning jets away from undesired objects by use of secondary electrodes.