Nanoadhesion and Nanopeeling Forces of Carbon Nanotube on Substrate

Detachment and peeling experiments are expected to provide information on adhesion forces and adhesion energies of solid surfaces in contact. Such experiments are important in powder technology, in the formation of adhesive films and in understanding how cracks propagate in solid and how fracture occurs (Israelachvili, 1992). Recently, nanoscale peeling has been studied by extending biological polymer chains such as proteins using atomic force microscopy to clarify the mechanical mechanism of unfolding of the polymer chain. Such experiments have attracted much attention worldwide as a new method of spectroscopy for the structural analysis of biological macromolecules (Evans et al., 1991, Rief et al., 1997). On the other hand, it has been more recently reported that carbon nanotube arrays with a curly entangled top show a macroscopic adhesive force of approximately 100 newtons per square centimeter, almost 10 times that of a gecko foot, and a shear adhesion force much stronger than the normal adhesion force (Qu et al., 2008). Here, we report the elementary processes of adhesion and peeling of a nanotube on a substrate and have performed adhesion and peeling experiments using a multiwalled carbon nanotube (MWCNT) (Ishikawa et al., 2008, 2009). An MWCNT has been attached parallel to the cantilever to easily peel off the substrate to elucidate the elementary process of adhesion and peeling mechanisms.