Wire coil needleless electrospinning of polymer nanofibers

Elcctrospinning is a very useful technique to produce polymeric nanofibers for diverse applications. The conventional needle-based electrospinning system has VCIY limited fiber productivity and a key challenge has been to develop electrospinning systems that can produce uniform nanofibcrs on a large scale l-3.In this study, we have demonstrated that a rotating metal wire coil can be used as a nozzle to eiectrospin nanofibers on a large-scale. Without using any needles, the rotating wire coil, partially immersed in a polymer solution reservoir, can pick up a thin layer of charged polymer solution and generate a large number of nanofibers from the wire surface simultaneously. This arrangement significantly increases the nanofiber productivity.The fiber productivity was found to be determined by the coil dimensions, such as wire diameter, coil radius and distance, and coil length. The effects of applied voltage, the distance bctv,lcen the coil nozzle and collector, and polymer concentration on the fibermorphology were examined. The dependency of fiber diameter on the polymer concentration showed a similar trend to that for a conventional electrospinning system using a syringe needle nozzle, but the diameter distribution was narrower for thecoil electrospun fibers.The profiles of electric fIeld strength in coil electrospinning was calculated and showedconcentrated electrical field intensity on the top wire surface. This novel concept of using wire coil as the electrospinning nozzle will contribute to the further development of new large-scale needleless electrospinning systems for nanofiber production