Mechanical characterization of nanofibers using a nanomanipulator and atomic force microscope cantilever in a scanning electron microscope

The mechanical characterization of polymeric nanofibers is essential to explore the potential for their applications in structural materials, such as nanofiber-reinforced polymer composites. A ‘hooking’ method using a nanomanipulator and atomic force microscope (AFM) cantilever was developed in a scanning electron microscope (SEM). First, a single electrospun nanofiber was suspended over a trench in a substrate. The midpoint of the nanofiber was then hooked by the AFM cantilever. As the AFM cantilever moved in the transverse direction of the nanofiber, the nanofiber was elongated until it fractured. The hooking and elongation processes were controlled by a nanomanipulator. This method features an affordable configuration and loading mechanism, because it does not rely on the firm grip of the nanofiber at both ends. Nanofibers with different diameters were tested using this method, demonstrating that nanofibers with a smaller diameter have greater strength and, thus, are highly suitable for use as a nano-reinforcement in composite applications.