Gas Assisted Electrospinning
In “gas assisted melt electrospinning a heated gas stream is applied to one of two or multiple axial jets. The heated gas jet can secure the nozzle heating for inner melt jet(s) and thus delay solidification. The high flow rate of heated gas stream can keep providing additional drag force to the jet surface, leading to thinner fibers with higher production rate. As a result, due to additional deformation caused by the heated gas stream, submicron scale fibers can be obtained from melt electrospinning even without inducing a whipping motion. Without the whipping motion of the polymer jet, a guide channel for the melt jet surrounded by a heated gas stream can be installed to control the orientation and layout of nanofibers. If the inner channel is used for a gas stream, the resulting fibers can possess a hollow structure along the fiber axis. As the heated gas goes through the outer channel of spinneret, temperature of a molten polymer in the inner channel of the spinneret is kept high, and furthermore, the ejected heated gas jet offers additional thinning of the melt jet due to huge tangential drag force. Since the temperature, quantity and velocity of the gas stream can be controlled in the gas assisted melt electrospinning (GAME) process, various polymers can be used to produce much thinner fibers with higher production rate than the conventional melt electrospinning. Secondly, the controlled gas runs through the inner channel of spinneret, while the molten polymers go through the outer channel. The inner gas stream can prevent the outer melt jet being collapsed, and thus the resulting fibers can possess a hollow structure along the fiber axis.” (Cornell University, 2/28/2011)
Recent Journal Articles
10/29/2010
Nanofibers from gas-assisted polymer melt electrospinning
(4140-4144) Polymer 51 #18 (2010)
Zhmayev, Cho and Joo of Cornell University, New York found that gas-assisted electrospinning allows for reduced quenching of the melt jet in the spinning region, and thus increasing the jet attenuation rate and resulting in production of sub-micron scale fibers. A comprehensive melt electrospinning model showed the effects of the heated air stream on the polymer jet. It was found that during the electrospinning of polylactic acid (PLA) melt, air drag produced an additional 10% thinning compared to the un-assisted melt electrospinning process, and the heating provided by the air stream resulted in an additional 20-fold jet thinning. (RDC 12/19/2010)