This constant pressure type feed works better for lower viscosity feedstocks. Scaling-up possibilities Alternating current electrospinning Needleless (also known as, nozzle-free) electrospinning Multiplying the needles High-throughput roller electrospinning Wire electrospinning Bubble electrospinning Ball electrospinning High speed electrospinning Plate edge electrospinning Bowl electrospinning Hollow tube electrospinning Rotary cone electrospinning Spiral coil electrospinning Electroblowing Other techniques Modification of the spinneret and/or the type of solution can allow for the creation of fibers with unique structures and properties. Electrospun fibers can adopt a porous or core–shell morphology depending on the type of materials being spun as well as the evaporation rates and miscibility for the solvents involved. For techniques which involve multiple spinning fluids, the general criteria for the creation of fibers depends upon the spinnability of the outer solution. This opens up the possibility of creating composite fibers which can function as drug delivery systems or possess the ability to self-heal upon failure. Co-axial electrospinning A coaxial setup uses a dual-solution feed system which allows for the injection of one solution into another at the tip of the spinneret. The sheath fluid is believed to act as a carrier which draws in the inner fluid at the Taylor Cone of the electrospinning jet. If the solutions are immiscible then a core shell structure is usually observed. Miscible solutions however can result in porosity or a fiber with distinct phases due to phase separation during solidification of the fiber. For more advanced setups, a triaxial or quadaxial (tetra-axial) spinneret can be used with multiple solutions. Emulsion electrospinning Emulsions can be used to create core shell or composite fibers without modification of the spinneret. However, these fibers are typically more difficult to produce compared to coaxial spinning due to the greater number of variables which must be accounted for in creating the emulsion. A water phase and an immiscible solvent phase are mixed in the presence of an emulsifying agent to form the emulsion. Any agent which stabilizes the interface between the immiscible phases can be used. Surfactants such as sodium dodecyl sulfate, Triton and nanoparticles have been used successfully. During the electrospinning process the emulsion droplets within the fluid are stretched and gradually confined leading to their coalescence. If the volume fraction of inner fluid is sufficiently high, a continuous inner core can be formed. Electrospinning of blends is a variation of this technique which uses the fact that polymers are generally immiscible