Hierarchical-structure-dependent high ductility of electrospun polyoxymethylene nanofibers

Two types of electrospun polyoxymethylene nanofibers with rough and smooth surface morphologies [rough fibers (RFs) and smooth fibers (SFs), respectively] were successfully prepared via the control of the electrospinning voltages. Mechanical tensile tests showed that the RF nonwoven mats exhibited a much higher elongation (440%) than the SFs (180%) without sacrifices in the stiffness and strength. Scanning electron microscopy characterization revealed that the large ductility of a single RF resulted from its unique multiple-necking mode, which was induced by its rippled structural features. In the meantime, the large ductility led to a high molecular orientation under tension and further improved the strength and toughness of the RF nonwoven mats. In comparison, the SF behaved in a single-necking deformation mode, and this led to a rapid rupture behavior. This surface-morphology-dependent mechanical behavior helped us to deeply understand the relationship between the structure and properties and should guide the development of high-performance materials for load-bearing applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 47086.