An apparatus and methods for
electrospinning polymer fibers and membranes are described. The methods include in one aspect
electrospinning a
polymer fiber from a conducting fluid containing the
polymer in the presence of a first
electric field established between a conducting fluid
introduction device and a ground source and modifying the first
electric field with a second
electric field to form a
jet stream of the conducting fluid. In another aspect the methods include forming an
electrospinning jet stream of the conducting fluid and electrically controlling the flow characteristics of the
jet stream. In yet another aspect the methods include forming a plurality of electrospinning jet streams of the conducting fluid and independently controlling the flow characteristics of at least one of the jet streams. The apparatus for electrospinning includes a conducting fluid
introduction device containing a plurality of electrospinning spinnerets for delivering the conducting fluid, a ground member positioned adjacent to the spinnerets, a support member disposed between the spinnerets and the ground member and movable to receive fibers formed from the conducting fluid, and a means for controlling the flow characteristics of conducting fluid from at least one spinneret independently from the flow characteristics of conducting fluid from another spinneret. An improved conducting fluid
introduction device which includes a plurality of spinnerets, each for independently delivering a controlled quantity of conducting fluid at a controlled pressure or flow rate, the spinnerets being charged at an
electric potential and being disposed relative to each other to normally interfere with the electric field produced by adjacent spinnerets, each of the spinnerets having a tip at which conducting fluid exits configured to have an electrostatic
field strength at each tip stronger than the liquid
surface tension at each of the tips is also described.