Wetting and wetting transitions on copper-based super-hydrophobic surfaces

Shirtcliffe, Neil, McHale, Glen, Newton, Michael and Perry, Carole (2005) Wetting and wetting transitions on copper-based super-hydrophobic surfaces. Langmuir, 21 (3). pp. 937-943. ISSN 0743-7463

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Abstract

Rough and patterned copper surfaces were produced using etching and, separately, using electrodeposition. In both of these approaches the roughness can be varied in a controlled manner and, when hydrophobized, these surfaces show contact angles that increase with increasing roughness to above 160degrees. We show transitions from a Wenzel mode, whereby the liquid follows the contours of the copper surface, to a Cassie-Baxter mode, whereby the liquid bridges between features on the surface. Measured contact angles on etched samples could be modeled quantitatively to within a few degrees by the Wenzel and Cassie-Baxter equations. The contact angle hysteresis on these surfaces initially increased and then decreased as the contact angle increased. The maximum occurred at a surface area where the equilibrium contact angle would suggest that a substantial proportion of the surface area was bridged.

Item Type:	Article
Uncontrolled Keywords:	superhydrophobic, Lotus effect, wetting
Subjects:	F100 Chemistry F200 Materials Science F300 Physics
Department:	Faculties > Engineering and Environment > Mathematics, Physics and Electrical Engineering
Depositing User:	Glen McHale
Date Deposited:	17 Aug 2012 10:26
Last Modified:	12 Oct 2019 19:06
URI:	http://nrl.northumbria.ac.uk/id/eprint/8334

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