Adhesion and Friction on the Nanometer Scale: Energy Dissipation During Sliding of Antimony Islands on Graphite and MoS₂

Antimony nanoparticles grown on highly oriented pyrolytic graphite and molybdenum disulfide were used as a model system to investigate the contact area dependence of frictional forces. Controlled translation of the antimony nanoparticles was induced by the action of the oscillating tip in a dynamic force microscope. During manipulation, the power dissipated due to tip-sample interactions was recorded. We found that the threshold value of the power dissipation needed for translation depends linearly on the contact area between the antimony particles and the substrate. Assuming a linear relationship between dissipated power and frictional forces implies a direct proportionality between friction and contact area. Particles smaller than 10000 nm², however, were found to show dissipation close to zero. To explain the observed behavior, we suggest that structural lubricity might be the reason for the low dissipation in the small particles, while elastic multistabilities might dominate energy dissipation in the larger particles.