In 2009, another possible formation mechanism of 2D nanonets was proposed by Kim and coworkers, and they claimed that nanonets could be produced by tailoring the polar polymer solutions based on the inspiration of ionic salts. During the electrospinning process, high voltage allows the polymer solution to be charged and the resultant charge repulsion causes the solution to be deformed, forming the Taylor cone and its ejected jets. They thought that the formation of nanonets was attributable to the ions in the polymeric solution, and should occur at the place of formation of the main nanofibers. The nanonets can be considered as joints between the main fibers, and among the nanowires from the nanofibers, and between the nanowires and the nanofibers, which can be confirmed by transmission electron microscopy results, as shown in Fig. 8.4B and C. Taking into account the solvent evaporation process and randomly distributed state of the ions, the highly viscous solution at the tip end would be compelled to form joints because of the ionic balance among the unsolidified nanofibers, resulting in new nanowires after complete solidification. To further clarify the
