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C. Gachot, M. Hans, R. Catrin, U. Schmid, F. Mücklich:
"Tuned Wettability of Material Surfaces for tribological Applications in miniaturized Systems by Laser Interference Metallurgy";
Vortrag: SPIE Europe: Microtechnologies for the New Millennium, Dresden, Deutschland; 04.05.2009 - 08.05.2009; in: "Proceedings of SPIE", Society of Photo-Optical Instrumentation Engineers (SPIE), Vols. 7362-7266 (2009), 9 S.

Innovative surfaces are successful, if we succeed to put in the correct place the correct property with technological efficiency. Until now, material surfaces can be systematically structured in different ways in order to fulfil chemical or mechanical requirements such as corrosion protection or wear resistance for example. Moreover, the properties of materials are strongly related to their microstructure as well as to their spatial distribution. For that reason, the design of materials with tailored microstructures is a key for the functionalization of surfaces. This is possible by an artificial fabrication technique called Laser Interference Metallurgy.
In this context, textured or functionalized surfaces are beneficial in overcoming stiction and adhesion in MEMS devices. With regard to tribological applications, a systematic study of the effect of geometrically differing laser interference patterns on the wetting behaviour of metallic gold thin films with a thickness of about 300 nm and 125 μm thick polyimide foils should be presented. It could be shown that in case of gold films, a laser interference patterning
reinforces the hydrophilic sample behavior whereas the polyimide foils reveal a significant increase in hydrophobicity after the laser patterning process. Both wetting regimes are advantageous under dry or lubricated friction conditions. The corresponding geometrical limits of the abovementioned method concerning the structure depth, periodicity and pattern form has been determined. All the samples have been characterized by scanning electron and focused ion beam
microscopy and white light interferometry. Additionally, IR spectroscopy has been applied to the polyimide samples in order to separate topographic and chemical influences.

Laser Interference, Microstructured Surfaces, Wettability, Tribology

http://dx.doi.org/10.1117/12.821661