Nanomechanics of Peeling Studied Using the Atomic Force Microscope

Through adaptation of an atomic force microscope, we have developed a peel test at the micro- and nanoscale level that has the capability of investigating how long flexible nanotubes, nanowires, nanofibers, proteins, and DNA adhere to various substrates. This novel atomic force microscopy (AFM) peeling mode extends existing AFM “pushing” and “pulling” force spectroscopies by offering practical knowledge about the complex interplay of nonlinear flexure, friction, and adhesion when one peels a long flexible molecule or nanostructure off a substrate. The static force peeling spectroscopies of straight multiwalled carbon nanotubes suggest that a significant amount of the total peeling energy is channeled into nanotube flexure. Meanwhile dynamic force spectroscopies offer invaluable information about the dissipative physical processes involved in opening and closing a small “crack” between the nanotube and substrate.