A shield ring enhanced equilateral hexagon distributed multi-needle electrospinning spinneret

The multi-needle electrospinning system is a convenient way to produce fibers with special structures such as core-shell morphologies at a high production rate. In this paper, a specially designed multi-needle electrospinning system is presented. The spinnerets were built-up with an equilateral hexagon array. Each set of 3 needles of the spinnerets were distributed as an equilateral triangle. A coaxial shield ring was used to create an approximate uniform electric field near the tips of the needles and to restrict the collection area. The simulation results also show that the outside needles can help to create a more uniform electric field near the inside tips of the needles and restrict the path of the inside jets, which works almost the same as the additional shield ring. Based on the simulation results, several multi-needle systems were tested. A 7 cm diameter shield ring was used in a 7 needle system, a 9 cm diameter shield ring was used in a 19 needle system and a 10.5 cm diameter shield ring was used in a 37 needle system. Polyethylene Oxide (PEO) aqueous solution was used as the test solution in experiments. The electrospinning results demonstrated that the use of multi-needle spinnerets is robust and that uniform nanofibers can be produced. The more needles used, the smaller the mean fiber diameter for larger mean electric field strengths. These distributions of needles show the scale up possibility of special structure electrospun nanofiber manufacturing.