A surface that can't be wetted.

WBahn

Joined Mar 31, 2012
29,978
Water, oils and solvents maybe but I know plenty of chemical liquids that would eat this in a microsecond by 'burning' the air around it.
But that wasn't the claim. The claim is that liquids would be repelled by it.

It would be interesting to see how it behaved in the presence of a superfluid such as Helium.
 

nsaspook

Joined Aug 27, 2009
13,081
But that wasn't the claim. The claim is that liquids would be repelled by it.
The article header did say 'any liquid' but inside it said "The surface super-repelled all available liquids, including water, oils and many solvents, qualifying to be superomniphobic".

The liquid-air interface is what's important for that repelling action. The liquid energy barrier of the surface of the liquid depends on the density change IRT air to form and without it you have nothing that acts to repel.
 

#12

Joined Nov 30, 2010
18,224
So will it prevent marine bio fouling organisms. like slime and barnacles from growing on your boat?
That would be so good! Can't wait for somebody to hang a piece of this in the ocean for a few weeks.

(I hope there is no liquid helium in the ocean :eek: )
 
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GopherT

Joined Nov 23, 2012
8,009
Water, oils and solvents maybe but I know plenty of chemical liquids that would eat this in a microsecond by 'burning' the air around it.
Yes, but if you put those liquids in an inert atmosphere, they are no longer flaming and cannot damage the silica (glass) micro structures. The author did not say anything about ALL liquids in ALL atmospheres. Also, your flaming with pyrophoric compounds is like complaining that a hydrophobic substrate not flame proof - simply because the molecule catches fire non it's own,

The only things that would etch these surfaces are Hydrofluoric acid (HF) or hot concentrated caustic (NaOH) or (KOH or similar). Even those will take some time to erode the microstructure so, in my opinion, it does repel HF and NaOH (for some time).
 

GopherT

Joined Nov 23, 2012
8,009
This is actually a bio-inspired technology based on the "self-cleaning" effect of the lotus leaf. Arrays of Tiny spikes create a hydrophobic surface. Water beads up and rolls off the leaf and carries dust and dirt with it as is rolls off. The effect does work for anti-fouling of ship hulls but, unfortunately, sea water carries all kinds of abrasive crap that erodes/polishes the texture off over time.

I don't think the surface will ever be commercialized as it must be frown in a PVD or CVD or ALD process in a chip fabrication lab.


http://en.m.wikipedia.org/wiki/Lotus_effect
 

nsaspook

Joined Aug 27, 2009
13,081
Yes, but if you put those liquids in an inert atmosphere, they are no longer flaming and cannot damage the silica (glass) micro structures. The author did not say anything about ALL liquids in ALL atmospheres. Also, your flaming with pyrophoric compounds is like complaining that a hydrophobic substrate not flame proof - simply because the molecule catches fire non it's own,

The only things that would etch these surfaces are Hydrofluoric acid (HF) or hot concentrated caustic (NaOH) or (KOH or similar). Even those will take some time to erode the microstructure so, in my opinion, it does repel HF and NaOH (for some time).
What do you think a little CIF3 would do to these surfaces? We once used the stuff to clean CVD chambers but the insurance company didn't like the liability.
 

GopherT

Joined Nov 23, 2012
8,009
What do you think a little CIF3 would do to these surfaces? We once used the stuff to clean CVD chambers but the insurance company didn't like the liability.
I forgot about F2 and all of the surrogates of F2 like (ClF3). You would immediately have SiF4 vapor mixed with HCl and various mixtures of other Cl, Si, O and F containing species. But then again, unless compressed, F2 and ClF3 and SF4 are gases at room temperature and fall out of the author's scope of "Liquids". It would be interesting to see how long they would bead up on the surface if compressed into liquids.
 

sdowney717

Joined Jul 18, 2012
711
Here is SLIPS, which repels water, not based on the Lotus leaf hair idea, this is a flat surface coating.
http://www.gizmag.com/slippery-liquid-porous-surfaces-slips/22909/
And because SLIPS is so slippery, it also prevents proteins from adhering to a synthetic surface, meaning the technology could be used on the surfaces of medical devices, such as catheter tubes, stents, and various blood carrying tubes, to minimize blood clotting.
Article mentions some marine usage to prevent ice buildup is possible. Biofouling is all about a slime that first starts to grow on the hull, then barnacles, etc... come along and feel that slime and think this is a food surface to live on. So if it prevents proteins, maybe it could prevent slime from starting to grow.
http://www.gizmag.com/coating-makes-glass-tough-self-cleaning-slippery/28604/

Rustoleum Never Wet is not suitable for a boat, just not durable. I think it is a fad.
 

GopherT

Joined Nov 23, 2012
8,009
I wonder what effect this would have on the cavitation of a propeller?
I wouldn't wonder about it too long. There are other more important effects than surface energy.
It is like thinking that you will increase your top speed in your car by waxing your side mirrors.
 
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