Optimal spinneret layout in Von Koch curves of fractal theory based needleless electrospinning process

Abstract

Needleless electrospinning technology is considered as a better avenue to produce nanofibrous materials at large scale, and electric field intensity and its distribution play an important role in controlling nanofiber diameter and quality of the nanofibrous web during electrospinning. In the current study, a novel needleless electrospinning method was proposed based on Von Koch curves of Fractal configuration, simulation and analysis on electric field intensity and distribution in the new electrospinning process were performed with Finite element analysis software, Comsol Multiphysics 4.4, based on linear and nonlinear Von Koch fractal curves (hereafter called fractal models). The result of simulation and analysis indicated that Second level fractal structure is the optimal linear electrospinning spinneret in terms of field intensity and uniformity. Further simulation and analysis showed that the circular type of Fractal spinneret has better field intensity and distribution compared to spiral type of Fractal spinneret in the nonlinear Fractal electrospinning technology. The electrospinning apparatus with the optimal Von Koch fractal spinneret was set up to verify the theoretical analysis results from Comsol simulation, achieving more uniform electric field distribution and lower energy cost, compared to the current needle and needleless electrospinning technologies.

Multilayer Nanofiber Composite Separator for Lithium-Ion Batteries with High Safety

“…The inner diameter of the spinnerets was 69 mm, the outer diameter was 79 nm and the thickness was 2 mm. More details about the device can be found in our previous work [22]. PI electrospinning solution (30% by wt.)…”

“…We previously designed a needleless electrospinning device based on Von Koch fractal curves, which demonstrated better field intensity and distribution, and high productivity compared to multineedle electrospinning after simulation and analysis on the electric field. Further simulation and analysis by finite-element analysis software showed that the circular type of fractal spinneret with the second-level fractal structure exhibited better field intensity and distribution compared to other nonlinear fractal electrospinning technology (Figure 1) [22]. The present study takes advantage of the original needleless electrospinning device and employs it for the fabrication of composite nanofiber membranes for a lithium-ion separator.…”

Fractal-like multiple jets in electrospinning process

“…Liu et al [22] first found the lightning-like jets in the bubble electrospinning. The fractal theory was successfully applied to controlling the shape of 2-D materials [23], and to designing optimally the spinneret [24], and now the fractal theory has become a useful mathematical tool to complex phenomena [25,26]. Traditional electrostatic spinning device schematic diagram was shown in fig.…”

Enhancement of Coil Electrospinning Using Two-Level Coil Structure

“…They suggested that the spinneret with a larger curvature could form a higher electric field on a coil surface, which resulted in large nanofiber productivity and fine nanofibers with narrow diameter distribution. 12,16 Several researchers have reported on the increase in spinneret curvature by introducing an auxiliary structure onto needleless spinnerets, such as the Von Koch curve fractal structure, 17 needles on disk or helix slice, 18,19 barbed roller, 20 probed cylinder, 21 and threaded rod. 22 However, an uneven increase in local curvature can adversely lead to corona discharge and breakdown of the electric field.…”

“…Several researchers have reported on the increase in spinneret curvature by introducing an auxiliary structure onto needleless spinnerets, such as the Von Koch curve fractal structure, needles on disk or helix slice, , barbed roller, probed cylinder, and threaded rod . However, an uneven increase in local curvature can adversely lead to corona discharge and breakdown of the electric field. , Corona discharge not only increases the consumption of electrical energy, but also reduces the electrospinning efficiency and nanofiber production rate .…”