Enhanced mechanical properties of electrospun nano-fibers through NaCl mediation

Electrospun (ES) nano-scale polymer fibers are known to exhibit lower Young's modulus and strength than their bulk counterpart. We have discovered that minute additions of sodium chloride (NaCl) during the preparation stage of ES polymethyl methacrylate (PMMA) fibers raises the fiber mechanical properties in a significant way, nearly up to bulk values, over a range of diameters. NaCl-induced electrical effects leading to enhanced molecular alignment during nano-fiber formation is the most likely explanation for this synergistic effect. Moreover, beyond the now-recognized rise in Young's modulus values, we observed that the strength and tensile toughness of the ES fibers also significantly increase at progressively smaller diameters.