Berlin 2012 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 13: Poster: Interfaces and Thin Films

CPP 13.28: Poster

Dienstag, 27. März 2012, 18:15–20:45, Poster A

Morphology and rupture forces of liquid gallium immobilized on different surfaces — •Frank Lawrenz¹, Nikolai Severin², Jürgen P. Rabe², Christiane A. Helm¹, and Stephan Block³ — ¹Institut für Physik, Ernst-Moritz-Arndt Universität, Felix-Hausdorff-Str. 6, D-17487 Greifswald, Germany — ²Department of Physics, Humboldt-Universität zu Berlin, Newtonstr. 15, 12489 Berlin, Germany — ³ZIK HIKE - Zentrum für Innovationskompetenz Humorale Immunreaktionen bei kardiovaskulären Erkrankungen, Fleischmannstr. 42 - 44, D-17487 Greifswald, Germany

Liquid gallium is immobilized on mica, silicon and silica surfaces at 50 °C. AFM tapping mode imaging shows that gallium drops (micrometer-sized) as well as extended layers with nm-thickness and very low roughnesses are formed. Relatively large forces (on the order of several 10 nN) have to be applied to immerse a silicon tip (curvature radius around 10 nm) into the micrometer-sized gallium droplets. The forces exhibit many rupture events. The distribution of the rupture length is very broad and has a maximum at around 0.25 nm. It is most likely, that (solid) sheets of amorphous gallium oxide is formed at the air/liquid interface of gallium drops. These sheets interact with the AFM tip leading to the observed rupture events. Moreover, they are transferred during the preparation procedure to the surface forming the flat layers with nm-thickness.