Pressure-assisted spinning: A unique and versatile approach for directly fabricating membranes with micro- and nanofibers

Fibers are structurally interesting components most useful in a range of applications spanning the physical and life science areas of research. These membrane (scaffold) forming fibers have been explored in applications ranging from microfilteration to advanced biological investigations in tissue engineering to controlled and targeted drug delivery. One such robust fiber generation approach investigated for over a century, which has recently been exploited, is the well-established threading process referred to as electrospinning. In this technique, single- or multi-phase media are charged within a conducting needle and later exposed to an electric field which promotes the formation of a continuous micro- to nanosized fiber(s) which over a period of collection time has been reported for forming scaffolds and membranes. This process has been explored for a wide range of polymer composite-based materials and the technique has now reached the point where it has moved into industrial production. We report here as a first example a comparable fiber to membrane fabrication approach completely driven by the coupling of a coaxial needle system with a pressure. We refer to this novel methodology as pressure-assisted spinning (PAS) where the hazardous element of high voltage (as in the case of electrospinning) is nonexistent. Hence, our discovery introduces both a directly competing fiber, scaffold to membrane fabrication approach, which is versatile and has no associated hazards as those in electrospinning. Furthermore as our technique is nonelectricfield driven, the media spun into fibers could have a high electrical conductivity, which in this case has no effect on the stability in processing near-uniform fibers/scaffolds to membranes. The fabricated fibers and membranes generated by means of this approach could directly be used for a plethora of applications spanning the engineering and biological areas of research.