Massive Amplification of Surface-Induced Transport at Superhydrophobic Surfaces
- 8 August 2008
- journal article
- research article
- Published by American Physical Society (APS) in Physical Review Letters
- Vol. 101 (6), 064503
- https://doi.org/10.1103/physrevlett.101.064503
Abstract
We study electro- and diffusio-osmosis of aqueous electrolytes at superhydrophobic surfaces by means of computer simulation and hydrodynamic theory. We demonstrate that the diffusio-osmotic flow at superhydrophobic surfaces can be amplified by more than 3 orders of magnitude relative to flow in channels with a zero interfacial slip. By contrast, little enhancement is observed at these surfaces for electro-osmotic flow. This amplification for diffusio-osmosis is due to the combined effects of enhanced slip and ion surface depletion or excess at the air-water interfaces on superhydrophobic surfaces. This effect is interpreted in terms of capillary driven Marangoni motion. A practical microfluidic pumping device is sketched on the basis of the slip-enhanced diffusio-osmosis at a superhydrophobic surface.Keywords
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