| The study of sliding objects on surfaces at the nanometer scale is going to be increasingly relevant as fundamental and applied field of research. Understanding tribological properties and friction mechanisms is an important goal to grow new nanomaterials with tailored features and to optimize micro and nano systems with mutually mobile parts. A quantitative reliable AFM method has been recently introduced [1-4] to measure the depinning energy of distinct sizes of nanoparticles, deposited on different substrates, through the simultaneous acquisition and interpretation of phase images during tapping mode AFM operation. We demonstrate here that the fundamental controlling parameter is the energy dissipation taking place during the periodic interaction between tip and substrate. The extreme control of the excitation strength is obtained by tuning the tip oscillation amplitude while the dissipation effects are evaluated monitoring the phase shift signal. Example of different measurements and controlling scheme for gold nanocluster on graphite will be shown on the poster. |
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