Can Hydrophobic Surfaces Repel Both Water and Oil?

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psyklon
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Hello, I have a quick question regarding an http://www.sciencenews.org/view/generic/id/38466/title/Blueprint_to_repel_oil_and_water" that I just read on ScienceNews regarding hydrophobic surfaces.

In the second to last paragraph it's quoted that "although hydrophobic surfaces readily shed water, if they become contaminated with oily substances they lose their water repellency." The confusion I have (and I'm assuming that I'm wrongly inferring from the article) is that I regularly oil my work boots to ensure that they maintain their water repellency. So how does that make sense when oil-contamined surfaces lose their ability to repel water? :rolleyes:

Thanks!
 
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The article was probably talking about geometrically hydrophobic surfaces, which repel water because of their shape. The presence of oil changes the geometry, and the property is lost.

Workboots are not geometrically hydrophobic (yet), so you add oil to give the water less traction. This is an entirely different phenominon. With the newest research being done, however, it may not be long before you can buy a pair of workboots or a jacket or swimtrunks that will be hydrophobic or even superhydrophobic by nature; an inherent property of the fabric and not something that needs to be chemically added.
 
Thanks, LURCH. That definitely cleared up the issue for me. :biggrin: