Carbon nanotubes are useful in a variety of measurement applications. In the case of Atomic Force Microscopes (AFMs), carbon nanotubes can be affixed to the tip of the AFM cantilever to improve image resolution and enable images of surfaces with deep crevices and trench structures. In this paper, the mechanical response of long, straight, small walled carbon nanotubes (SWNTs) under compressive and tensile load is examined with an atomic force microscope. Multi-dimensional force spectroscopy (MDFS) is used to simultaneously measure the cantilever resonant frequency, deflection, and scanner motion. The acquired force curves reveal that the SWNT buckles shortly after contact is initiated. As the scanner continues to rise and then reverses direction, the SWNT undergoes a number of adhesion/sticking episodes, buckling, and slip events. The bulk properties of the nanotube are estimated by measuring the shift in natural frequency during tension. Finally, the carbon nanotube is modeled as an elastica in order to predict the post-buckled shape of the SWNT. By comparing the model results with MDFS results, the static coefficient of friction between the SWNT and a variety of surfaces is estimated. The study suggests that MDFS has a wide applicability for studying the mechanical and adhesive properties of various nanotubes, nanorods and nanofibers.

The adhesion of long, straight, single-walled carbon nanotubes to surfaces is examined using multidimensional force spectroscopy. We observed characteristic signatures in the deflection and frequency response of the cantilever indicative of nanotube buckling and slip-stick motion as a result of compression and subsequent adhesion and peeling of the nanotube from the surface. The spring constant and the elastic modulus of the SWNT were estimated from the frequency shifts under tension. Using elastica modeling for postbuckled columns, we have determined the static coefficient of friction for the SWNT on alkanethiol-modified gold surfaces and showed that it varies with the identity of the monolayer terminal group.