In situ Characterization of Nanomechanical Behavior of Free-standing Nanostructures

The present paper reports the development of an in situ nanotensilometer that enables highly reliable mechanical tensile testing on individual micro-/nano-scale structures. The device features independent measurement of force and displacement histories in the specimen with nanoNewton force and sub-nanometer displacement resolutions, respectively. Moreover, the device is well suited for in situ testing of free-standing micro/nano-structures within a high resolution scanning electron microscope (SEM), which permits continuous high-resolution imaging of the specimen during straining. The device is comprised of two main parts: (a) a three-plate capacitive transducer that doubles up both as an actuator and a force sensor, and (b) a commercially available nanomanipulator that facilitates transportation and positioning of nanoscale structures with sub-nanometer precision. In order to conduct the mechanical tests the ends of the specimen are attached to the probe tips of the device using ion-beam induced deposition. The general capabilities and features of the nanotensilometer are illustrated by presenting results of nanomechanical tensile tests on electrospun polyaniline microfibers.