Electrospun nanofibers from a porous hollow tube

Single electrospinning jets are known to have low production rates. A 0.1 m2 nonwoven mat containing 1 g of 100 nm fibers may take several days to create from a single jet. Inexpensive methods of higher production rates are needed for laboratory research applications. In this paper we present experimental results of many simultaneous electrospinning jets from the surface of tube having a porous wall. The pores in the wall are small and resist the flow of the polymer. Holes drilled half way into the wall of the tube provide points of reduced flow resistance. A polymer solution of 15 wt% polyvinylpyrrolidone (PVP) in ethanol is pushed by low air pressure of 1-2 kPa through the tube wall at the drilled holes. On the outer surface of the tube polymer drops form at the locations of the drilled holes. The solution is charged from 40 to 60 kV to electrospin the polymer. Multiple polymer jets launch from the tube surface and form fibers. A 13 cm long tube with 20 holes can produce 0.3-0.5 g/h of nanofiber. Production rates can easily be scaled by increasing the tube length and the number of holes.