ABSTRACT
Needle electrospinning has been used extensively in research labs to produce a small quantity of nanofiber samples or as a model in theoretical analysis to understand the basic electrospinning process. Electrospinning systems with large-scale nanofiber production abilities have been explored, and some inspiring results have been achieved. This chapter summarizes the recent research progress in large-scale electrospinning technologies. 3.1 Downward Multi-Jet ElectrospinningA straightforward way to increase the electrospinning throughput is to use multi-jet spinnerets as shown in Fig. 3.1a. The fiber productivity can be simply increased by increasing the jet number [411, 412]. However, multi-jet electrospinning has shown strong repulsion among the jets, and this may lead to reduced fiber production and poor fiber quality, which is the main obstacle for its practical application. To reduce the jet repulsion, jets have to be set at an appropriate distance apart, and a large space is required to accommodate the needles for the mass nanofiber production. To stabilize and optimize the electrospinning process, an extra-cylindrical electrode has been used as an auxiliary electrode to cover the multi-jet spinneret [413]. As shown in Fig. 3.1b, the presence of
the external electrode dramatically reduced the fiber deposition area, thus improving the fiber production rate. Nevertheless, coarser fibers were observed, because the auxiliary electrode shortened the chaotic motion of multi-jets in electrospinning.
