Multiplex Electrospinning for Polymer Deposition and Novel Macroscale Structures

Applications of electrospinning (ES) range from fabrication of polymer-based biomedical devices to light manipulation and energy conversion, and even to deposition of materials that act as growth platforms for nanoscale catalysis. One major limitation to wide adoption of electrospun materials is the ES hardware itself, which typically requires high-voltage electrical isolation and charged and flat deposition surfaces. In the past, fabrication of polymer structures or materials with precisely determined mesoscale morphology has been accomplished through modification of electrode shape, use of multi-dimensional electrodes or pins, deposition onto weaving looms, hand-held electrospinners that allow the user to guide deposition, or electric field manipulation by lensing elements or apertures. In this work, we demonstrate an ES system that contains multiple high voltage power supplies that are independently controlled through a control algorithm implemented in LabVIEW. The end result is what we term “multiplex ES” where multiple independently controlled high-voltage signals are combined by the ES fiber to result in unique deposition control. COMSOL Multiphysics® software was used to model the electric field produced in this novel ES system. Using the multi-power supply system, we demonstrate fabrication of woven fiber materials that do not require complex deposition surfaces. Time-varied sinusoidal wave inputs were used to create electrospun tori shapes. Parametric analysis of tori diameter was found to be rather insensitive to frequency used during deposition, while inner diameter was inversely proportional to frequency, resulting in overall width of the tori to be proportional to frequency. The amount of control possible in multiplex ES is limited by the time response of high-voltage power supply output in relation to changes in input signal. Power supply time constants were measured and minimized through the addition of resistors that altered impedance of the system and improved response time up to 63 %.