Interaction forces between carbon nanotubes and an AFM tip

AFM force curve meaurements have been performed on layers of entangled multiwall carbon nanotubes, produced by chemical vapor deposition, to measure the nanotubes adhesive and elastic properties. AFM tip radius and nanotube diameter being comparable, these layers are a discrete medium for the force curve measurements. Controlling the tip-layer interaction, we can specifically probe the response of one or several nanotubes. If the tip is strongly pressed against the layer, it interacts with several nanotubes; for a weak interaction, it interacts with only one nano-object. Non-linear behavior in force curves is an evidence for an inelastic response of the nanotubes. Numerical simulations of the layer-AFM tip system mechanical analysis reproduce all the nanotubes adhesion and mechanical experimental features.