Nanofiber solidification

The process of collecting fluid jets involves coils formed by electrical bending, branching, conglutinated networks of fibers and garlands and the solidification of the thin jets produces nanofibers with the occurrence of nucleation and crystallization inside the nanofibers. Phase separation of both polymer blends and block copolymers can be observed. 

In Ref. 65 the authors also take into account effects due to the evaporation of solvent vapors and to the resulting solidification process occurring in nanofibers during the jet flight, obtaining an equation that describes the temporal variation of the jet volume ... 

Rapid solvent evaporation and solidification of the electrospun fibers during electrospinning, decreases the domain coarsening, so there are fine and stretched phase domains in the nanofibers, and carbon nanofibers with a large amount of nanopores throughout the surface and the interior of the fibers were obtained. The nanopores in the fibers at about several tens of nanometers in widths are continuous. Great potential of the nanoporous carbon fiber obtained in this study make many interesting applications for them in different fields [8]. 

In addition to the use of monomers, it is possible to form nanofibers directly from a polymer solutioa In this case, the polymer solution is filled into the hollow chaimels and solidified into nanofibers by removing the solvent. Nanofibers produced from the polymer solution typically have laiger diameters than those synthesized from monomers. This is because of the high viscosity of polymer solutions, which does not allow the use of hollow channels with very small diameters. Figure 13.14 shows a SEM image of PAN nanofibers prepared by filling the hollow channels of a porous aluminum oxide template with a PAN solution, followed by polymer solidification and template removal. 

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