Shear-aided annular needleless electrospinning

We briefly introduce a new approach for electrospinning in this paper. The novel high-speed electrospinning setup we invented involves a spinneret consisting of a cylindrical rotor placed within a concentric stator, both having a sharp metal edge. The solution gets out of the spinneret at the annular orifice in between these two edges forming a narrow liquid meniscus from which electrospinning jets are initiated. The setup applies mechanical shearing on the electrospinning solution. As the shear rate is increased (via the rotation speed) the viscosity of the shear-thinning solution decreases leading to enhanced Taylor-cone formation and the initiation of multiple jets. The throughput can be several orders of magnitude higher than that of the single capillary method and seems to be limited mainly by the evaporation rate of the solvent. With the small spinneret we reached 20 ml h(-1) throughput for poly(ethyle oxide) solutions. The average fiber diameters decreased from 297 nm to 202 nm by applying shearing within the annulus.