Effects of electric field and polymer structure on the formation of helical nanofibers via co-electrospinning

Fabrication of helical nanofibers via coelectrospinning has been of increasing interest due to its simplicity and lowcost. Many variables are important for the formation and properties of the resultant helical fibers. In this paper, the effects of electric field and material factors on the helical fiber formation are explored. The role of the electric field is studied for three coelectrospinning systems, off-centered core−shell, coaxial and side-by-side. Electric field simulations are performed to explain the experimental results. To explore the effect of material factors on the fiber formation, three polymer systems, Poly(mphenylene isophthalamide) (Nomex)/polyurethane (TPU), polystyrene (PS)/TPU and polyacrylonitril (PAN)/TPU are used. By analyzing the polymer structure, interface interaction between the two phase of the system, and the dissolution of the polymer, the Nomex/TPU system has been identified to have the best potential for producing helical nanofibers.