ABSTRACT
A coaxial setup allows for the injection of one solution into another at the tip of the spinneret by using a multiple solution feed system. The sheath uid acts as a carrier, which draws in the inner uid at the Taylor Cone of the electrospinning jet.15 If the solutions are immiscible, then a core shell structure is usually observed. Miscible solutions, however, can result in porosity or a ber with distinct phases due to phase separation during solidication of the bers. Taylor cones may be stationary, but they are never static features. Their apices are always the source of emission of charged particles under a rich range of regimens. In this regimen, a steady jet issues continuously from the cone apex, eventually breaking into a spray of charged drops or electrospray (Figure 55.1). This steady regimen is not only the best known but also the simplest to analyze, but the limit of high electrical conductivity of the liquid, where the jet radius is typically smaller than 1 µm, enables a division of the problem into two regions. Outer domains (the cone), which are effectively hydrostatic, are slow and have little inuence on jet formation, in which the liquid behaves as innitely conducting, and an inner region, which is dynamic and where a very ne jet carrying a nite current and ow rate forms. Taylor cones of highly conducting liquids offer the only known scheme to produce submicrometer and nanometer jets (down to a diameter of about 10 nm).
