Effect of Ionic Salts on the Structure of Electrospun Gelatin Nanofibers

The fabrication of gelatin nanofibers by electrospinning has been examined using the TFEA/W co-solvent system. It has been found that no beads-on-string structure was formed for the solution containing ionic salts. The resulting fibers exhibited a uniform diameter ranging from I 10 to 125 nm. As the concentration of ionic salts increases, the beads become smaller and more spindle like, due to the increase of viscosity and conductivity. The addition of ionic salts induces a higher charge density on the surface of ejected jet during spinning, leading that higher elongation forces are applied to the jet. The higher enhancement of viscosity and conductivity was observed in gelatin solutions by the use of divalent salt. However, the concentration of ionic salts scarcely affected the variation of fiber diameter. While very low crystallinity was observed from XRD pattern for the sample containing no ionic salt, which increased with increasing the concentration of ionic salts.