Measurement of shear stress between single-wall carbon nanotubes and substrates using NEMS devices

This paper presents a novel and easily controllable method for measurement of the interaction of single-wall carbon nanotubes (SWNTs) with surfaces using simple cantilever beams, a nanomanipulator, and a scanning electron microscope (SEM). A small SWNT bundle is assembled across two cantilevers by dielectrophoresis, with one cantilever much more flexible than the other. The flexible cantilever is then pushed away from the stiffer cantilever in order to produce slip between the SWNTs and the cantilever surface. When the cantilever returns to its initial position, axial slack is observed in the SWNTs. A theoretical model has been developed to calculate the shear stress between the SWNT bundle and the cantilever surface, based on the measured axial slack. For a gold cantilever surface, an average interfacial shear stress of 113 MPa was obtained.