I've been wondering the same thing... Besides, there are other differences between lab environment and the "real world" - actual water is full of impurities (e.g. limescale, urea in pee, mud, salt, acid rain, ...), I wonder if the material retains its hydrophobic properties. The other thing that worries me probably even more than "wear-and-tear" (i.e. scratches, abrasion, ...) is dust - once dust covers the fine nano-structure, water will once again stick to it, and it might well be impossible to clean!
Dust, at least, is not an issue like you suspect. The researchers who developed this technique took the dust from a vacuum cleaner and dumped it on a treated piece of metal; water picks up the dust and then slides right off, so the surface is actually incredibly easy to clean.
Sure, but if you dump something on it which has a grain size that's similar to the voids in the material, all bets are off. If the average void is 1um and you put 0.1um dust all over it, I would suspect that it would embed itself in there pretty nicely.
Or a liquid that's not repelled by the surface. What would happen if you just dumped a lot of washing up liquid on this nanosurface? How would you rinse it off?
Watching the video I thought the thing with the teflon was a bit silly. After all if you wanted to think of something that won't hold water at an angle, wouldn't you think of ordinary glass rather than teflon?
Water doesn't dissolve oil, although it could help mechanically remove it -- but if the material is actually olephilic or neutral it could be an issue.
I was wondering what would happen if you turned on a firehose and just slammed it for a good length of time...how durable it would be? If they're planning to use it on the surface of an airplane wing -- curious how durable the surface is.
Durability? reaction to other biological substances? I'm thinking of artificial heart valves and the necessity of preventing anything sticking for upwards of 50 years of continuous use.
> Instead of using chemical coatings they used lasers to etch a nanostructure on the metal itself. It will not wear off, like current less effective methods.
About the plane wing applications... Wouldn't these micropatterns also have some kind of impact on aerodynamics? Not saying it's even a negative thing, but more research seems to be needed.
This will work really well. Some leaves use this same mechanism to 'self-clean', which means that now we will have the ability to add the 'lotus effect' to man-made objects.
On the 2nd floor of Wean Hall at CMU somebody has sprayed a small patch of hydrophobic coating on one of the urinals (I think it's the 2nd floor, but definitely it's floor 2, 4, or 5). The stream normally turns into a "sheet" falling down the back of the porcelain, except around the patch -- where it hops off and turns into a thousand little droplets that bounce merrily down to the drain. Unless the person who put it there keeps re-applying it, the coating has had an impressive lifespan (at least 1 year in a semi-public toilet). Anyway, if you happen to be in the area (and male) you can try it yourself.
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[ 0.32 ms ] story [ 97.0 ms ] threadWatching the video I thought the thing with the teflon was a bit silly. After all if you wanted to think of something that won't hold water at an angle, wouldn't you think of ordinary glass rather than teflon?
(Source: I worked on and designed equipment for commercial scale-up of a nanoscale superhydrophobic coating process)
Water doesn't dissolve oil, although it could help mechanically remove it -- but if the material is actually olephilic or neutral it could be an issue.
> Instead of using chemical coatings they used lasers to etch a nanostructure on the metal itself. It will not wear off, like current less effective methods.
http://www.rochester.edu/newscenter/superhydrophobic-metals-...
http://scitation.aip.org/docserver/fulltext/aip/journal/jap/...
https://www.youtube.com/watch?v=VHcd_4ftsNY
Probably isn't handled too much though.