Berlin 2005 – wissenschaftliches Programm
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O: Oberflächenphysik
O 34: Rastersondentechniken II
O 34.2: Vortrag
Montag, 7. März 2005, 11:00–11:15, TU EB407
Interface dependent frictional forces: Study of amorphous and crystalline nanoparticles by dynamic scanning force microscopy — •Claudia Ritter1, Udo D. Schwarz2, Markus Heyde1,3, and Klaus Rademann1 — 1Humboldt-Universität zu Berlin, Institute of Chemistry, Brook-Taylor-Str. 2, D-12489 Berlin, Germany — 2Department of Mechanical Engineering, Yale University, P.O. Box 208284, New Haven, CT 06520-8284, USA — 3Fritz-Haber-Institute of the Max-Planck-Society, Faradayweg 4-6, D-14195 Berlin, Germany
The fundamentals of friction, in particular, the interplay between friction, adhesion, true contact area and crystalline structure at the interface, are still insufficiently understood. In this investigation, antimony nanoparticles grown on HOPG and MoS2 were used as a model system to investigate the contact area dependence of frictional forces. The morphology of the nanoparticles was characterized by Scanning Force Microscopy (SFM) and Electron Microscopy (SEM, TEM). Thus, both the interface structure and the real contact area were accurately determined. The TEM study revealed a size dependent amorphous-polycrystalline phase transition. Controlled translation of the particles was induced by the action of the oscillating tip in dynamic mode SFM. During manipulation, the power dissipated due to tip-sample interactions was recorded. Particles with contact areas below 10000nm2 were much easier to move compared to their larger counterparts. We suggest that structural lubricity might be the reason for the low dissipation in the small amorphous particles, while elastic multistabilities might dominate energy dissipation in the larger polycrystalline particles.