Regensburg 2010 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 43: Colloids and Complex Liquids II

CPP 43.10: Talk

Thursday, March 25, 2010, 16:30–16:45, H39

Sliding of colloidal monolayers on periodic and quasiperiodic substrate potentials — •Thomas Bohlein, Jules Mikhael, and Clemens Bechinger — 2. Physikalisches Institut, Universität Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart, Germany

Quasicrystal surfaces exhibit low friction coefficients. This anomalous property led to their consideration as coatings for tribological applications. However, the fundamental mechanisms behind this behavior are still not well understood. Here we experimentally study the sliding behavior of two dimensional colloidal crystals interacting with periodic and quasiperiodic light induced substrate potentials created by overlapping several laser beams. A precise control of the phases of the interfering beams allows us to shear the substrate potential against the crystal in any desired direction while the crystal's response is studied in real space by digital video microscopy. We study how the substrate strength, the sliding velocity and the matching of the length scales affect the sliding behavior. This allows us to identify the role of quasiperiodicity on the friction behavior which leads to a better understanding on the fundamentals of atomic fiction and superlubricity.