Sunday, January 20, 2013

A New Surface Coating that Repels Almost All Liquid


Scientists at the University of Michigan published a paper and released the obligatory press release on their development of a new method of coating surfaces. Oh, the press release isn't that bad as it's easily comprehensible. Here's how the scientists' abstract describes the result:
Superomniphobic surfaces display contact angles >150° and low contact angle hysteresis with essentially all contacting liquids. In this work, we report surfaces that display superomniphobicity with a range of different non-Newtonian liquids, in addition to superomniphobicity with a wide range of Newtonian liquids. Our surfaces possess hierarchical scales of re-entrant texture that significantly reduce the solid–liquid contact area. Virtually all liquids including concentrated organic and inorganic acids, bases, and solvents, as well as viscoelastic polymer solutions, can easily roll off and bounce on our surfaces. Consequently, they serve as effective chemical shields against virtually all liquids—organic or inorganic, polar or nonpolar, Newtonian or non-Newtonian.
Look, I hate it when people pick on intellectual work for being written above their level, and I am trying to avoid going there (mostly because I don't want to admit this is above my level) -- and I don't mind looking up the words I don't understand. "Superomniphobia" doesn't appear in any of the dictionaries I've checked, though what the authors mean isn't too hard suss out. ("Hydrophobia" is resistance to wetting with water. Although "omniphobia" is commonly used to mean the human fear of everything (also known as "panphobia"), it apparently has been co-opted to mean resistance to wetting by many types of liquids -- even "viscoelastic polymer solutions" -- not just water. So then you've got "supermoniphobia." I think they just like making up words. Also they should use "fluid" not liquid.) So out of respect for you I've added links for the other non-obvious parts of the description.

The science of "wetting" is actually a hot area, and there are a recent spate of "superomniphobic" coatings. Here's another really cool video:

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