The new PNAS study provides an instructive example for the close relation between basic research and technological development in the micro- and nanoregime: open systems with directly accessible surface channels can be used for micro- and nanofluidic applications but only if one carefully matches the channel geometry with the substrate wettability. This constraint is a direct consequence of the strong capillary forces that dominate in the micro- and nanoregime and can be formulated in a quantitative way using the methods of theoretical physics. In general, the development of any new technology requires a systematic understanding of the underlying physics. This latter constraint applies to all length scales: if one wanted to build a robot which walks over water, for instance, a human-like robot is a bad idea while a spider-like robot is a much better choice.
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Original work:
Ralf Seemann, Martin Brinkmann, Edward J. Kramer, Frederick F. Lange, Reinhard Lipowsky Wetting morphologies at microstructured surfaces PNAS 102, 1848-1852, February 8, 2005, 10.1073/pnas.0407721102