Simple Method Yields A Wrinkly, Durable, Water-Repellent Coating (acs.org) 76
ckwu writes: Superhydrophobic coatings that make water droplets dance and roll off of a surface show promise for applications such as self-cleaning cars, buildings, and food processing equipment. A new method creates a durable superhydrophobic coating by combining two common materials -- Teflon and a shrinkable plastic -- in a few simple steps. The researchers took inspiration from work done with the polystyrene material found in Shrinky Dinks -- the children's crafting kit. They deposited Teflon onto a similar material called PolyShrink, heated it, and found that the Teflon formed a crinkled surface that caused water to bead and roll off easily. The best results came from polyolefin shrink wrap coated with a 10nm-thick layer of Teflon. What's more, the surface is durable, having about the same scratch resistance as an aluminum coating, and repels water even after being scratched. Update: 03/09 16:10 GMT by T : Note: That's nm, rather than mm; now fixed.
10 nanometer, not 1 cm (Score:5, Informative)
Re:10 nanometer, not 1 cm (Score:4, Informative)
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and stop rust
Re:10 nanometer, not 1 cm (Score:5, Funny)
What's a factor of a million between friends?
Meeting aliens (Score:1)
I know, right?
Why can't we all use universal measurements like the meter (1 ten millionth the distance through Paris from the pole to the equator), or the second (1/86400 of the mean solar day), or the kilogram (mass of a lump of metal in Paris, with no relevance to anything), the degree Kelvin ( 1/273.15 the temperature of the triple point of water)?
If we ever meet aliens, they would be totally confused by the American, which use traditional folklore measurements!
Re:Meeting aliens (Score:5, Funny)
Yeah, so if it takes 1 Calorie to raise 1cc of water 1K, and 1 Joule to raise 1cc of water 100m, how many Btus does it take to make an ounce of tea on Everest?
You can pick if it's a US or imperial ounce, but of course you'll need to express that in your answer.
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"If they had used the measure of one american dick they'd understand and it'd quite well be equal with 1 nm."
We don't talk about Donald Trump here.
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Why can't we all use universal measurements like the meter (1 ten millionth the distance through Paris from the pole to the equator)
That's not the definition of a metre.
or the second (1/86400 of the mean solar day)
That's not the definition of a second.
or the kilogram (mass of a lump of metal in Paris, with no relevance to anything)
Okay, got me there... but they're working on it!
Napoleon and the Academy of Science (Score:3, Interesting)
It went like this. A Meter (Metre in French, meaning step), was the distance stepped off by a french Legionnaire
in the time of Napoleon. Then he told his scientists, "Make it have some relevance to Science" and they came
up with this and that, eventually was the platinum bar at some temperature in the basement somewhere in
Paris. Then the modern scientists came into vogue, and it was 134567368 x the wavelength of some light
emited by an excited atom of some molecule.
I kinda like the Imperial better. Heave
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Actually I think the best of the non-metric measurements is temperature. Sure, its true, the metric scale is better for many things. It is great for talking about boiling water, and freezing water, and relating them.
However, its hard to talk about comfortable room temperatures in C without resorting to fractional numbers. The 0-100 range is just too wide for daily use.
The F scale however is based around the normal sorts of human temperature ranges where 0 is around where we start talking about it being dang
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However, its hard to talk about comfortable room temperatures in C without resorting to fractional numbers.
No it isn't. There's only a conversion factor of 1.8 between C and F. How often do you have conversations that go "It's warm outside, feels about 90." / "Nah, feels more like 88 to me."?
0 is around where we start talking about it being dangerously cold
0 is around where it starts to snow instead of raining (very roughly) or where your water pipes might start freezing. That point seems a bit more practical and definite to me than a less well-defined "dangerously cold."
Re:Meeting aliens (Score:4, Informative)
Why can't we all use universal measurements like the meter (1 ten millionth the distance through Paris from the pole to the equator)
That's not the definition of a metre.
Yes, that actually was the original definition.
From Wikipedia [wikipedia.org]:
"the commission â" whose members included Lagrange, Laplace, Monge and Condorcet â" decided that the new measure should be equal to one ten-millionth of the distance from the North Pole to the Equator (the quadrant of the Earth's circumference), measured along the meridian passing through Paris.
The definition has been revised several times to base it on bars made of platinum, the wavelength of light and the speed of light, but that doesn't change the origin of the unit.
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Yes, the kilogram was (is?) the mass of an object, but you can approximate it quite readily - one litre of water has a mass of one kilogram - water is fairly readily available.
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Was about to ask about this.
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10mm-thick layer of Teflon (Score:1, Insightful)
Do you write stupid shit on purpose to see if we're paying attention?
Re:10mm-thick layer of Teflon (Score:5, Funny)
I think it's more the Americans trying to work out this whole crazy newfangled metric system. Base 10 is just so friggin hard to grasp when you've accidentally shot off a bunch of your fingers.
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You're a fucking moron.
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I think it's more the Americans trying to work out this whole crazy newfangled metric system. Base 10 is just so friggin hard to grasp when you've accidentally shot off a bunch of your fingers.
That's a funny statement for someone from a British colony! (You do know that your ancestors were the ones that pushed the imperial system onto the US, right?)
As an American, I always figured that we kept those imperial units after the revolutionary war to remind ourselves what happens when the Brits are in charge!
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Yeah, that's probably a smart idea ;-)
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No, moron, we did not. PTFE is one of the least reactive substances in existence and is not dangerous to anyone at all. One of the chemicals *formerly* used in the production of PTFE was found to be toxic. The resulting coating is not.
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No, moron, we did not. PTFE is one of the least reactive substances in existence and is not dangerous to anyone at all. One of the chemicals *formerly* used in the production of PTFE was found to be toxic. The resulting coating is not.
As long as it isn't heated on the stove that is. Makes it pretty useless for frying pans though.
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It's about time! (Score:2)
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I've always hoped someone would take the values of Shrinky-Dink seriously.
Scientists have been making discoveries with shrinky-dink for years now.
Re: coating (Score:1)
The people on both sides are sheep. I'm fucking tired of sheep calling each other sheep.
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Teflon is incredibly toxic. Teflon is worse than shit.
Do you have a reference for that? I'd much rather cook in a teflon coated pan than a shit coated pan. Though admittedly I haven't done any testing.
Re:C8/PFOA (Score:5, Informative)
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Teflon IS NOT PTFE. "Teflon" is the brand name of "PTFE-based" formulas by Chemours. Chemours is a spin-off of DuPont Co. What reference to do have that C8 is "completely burned off"?
Pyrolysis of PTFE is detectable at 200 C (392 F), and it evolves several fluorocarbon gases and a sublimate.
While PTFE is stable and nontoxic at lower temperatures, it begins to deteriorate after the temperature of cookware reaches about 260 C (500 F). The degradation by-products can be lethal to birds, and can cause flu-like s
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the problem is that C8 is incredibly bad, but went uncontrolled for so long its no everywhere on the planet, and DuPont covered it up for the longest time (and continues to), knowing full well it was responsible for thousands of problems amongst thousands of people, both its workers and people living in the area of its plants and its secret dumping grounds. and its only one chemical out of the many tens of thousands about which very little if anything is actually known by the public, or even the manufacture
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and here I was thinking someone actually found something else teflon is good at (other than as pipe thread tape)....because pan coatings sure were a fucking flop.
The entire generation of people who chose teflon pans over cast iron were, quite simply, wrong.
Teflon is great non-stick, until you use it twice. Seasoned cast iron is constantly renewing its coating.
I wont go back.
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Teflon is incredibly toxic. Teflon is worse than shit. Dupont execs need to be locked away FOREVER. See src=https://en.wikipedia.org/wiki/Perfluorooctanoic_acid.
The reason Dupont was really bad there in terms of Teflon is not because Teflon requires PFOA, but because alternatives existed and Dupont still continued to use PFOA because it was cheaper (at least in the short run).
Why so much hate for water? Water is life.
Yes, water is life, which is why we want it to go some place more useful than soaking into inorganic surfaces.
Re:C8/PFOA (Score:4, Informative)
Perfluorooctanoic acid is not teflon, jackass. The process of MANUFACTURING teflon involves the process use of a toxic substance. So do a lot of substances. Chrome electroplating involves immersion a shockingly toxic bath. But finished chrome-plated items are not the least bit toxic, and neither are teflon-finished items, unless heated above 260 C, whereupon pyrolytic breakdown evolves toxic substances.
Since frying typically reaches up to 230 C, I don't regard the safety margin as adequate, and personally I would never fry in a teflon-coated pan. But no, teflon as a substance under ordinary conditions is NOT in the least toxic.
Caveat - if the finished teflon is allowed to be contaminated by traces of perfluorooctanoic acid, then there is trace toxicity present in the finished teflon. But the acid is NOT an integral constituent of teflon, does not HAVE to be used at all, and is being phased out. Overall, teflon cookware is considered an insignificant exposure pathway to perfluorooctanoic acid.
reduces contamination with dihydrogen monoxide (Score:4, Funny)
> Mumble mumble mumble chemicals safe mumble mumble.
On the other hand, the Teflon does reduce dihydrogen monoxide contamination on the surfaces, so it somewhat balances out.
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its not Teflon that's toxic.
its the manufacturing process.
yes, the company has a long and disgusting battle and coverup over the toxicity of C8 and the damage they've wrought on the environment, and as a result no place on the planet is currently uncontaminated by it (they've found it everywhere they've looked for it, even found it on ice in both the ARtcic and Antarctic, and the tissues of deep sea fish)
but C8 isn't present in Teflon itself.
its part of the manufacturing process, but virtually none makes it
a wrinkly car? (Score:2)
They almost had me.
It's not 10mm (Score:2, Informative)
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Yeah, that would be ... almost 1cm thick!
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That caught my eye as well - had to check the paper. A 10 mm coating would be... unimpressive.
Re: Wasn't there a superhydrophobic spray? (Score:3)
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As good a place as any to drop this...
In 1987, Gary Mull proposed exactly this technique for the Golden Gate America's Cup challenge. It was in a symposium for Berkeley, LBL, and LLNL Scientists and Engineers, and America's Cup Technical members.
It was among several other proposals that he made, all of which were subsequently Banned.
The point was to decrease the Hull water resistance at the point where Laminar Flow turns into Turbulent Flow, known as Transitional Flow. The Livermore folks were involved in t
Can it be washed? (Score:2)
Maybe I'm missing something, but all the praise seems to be around the ability to repel water.
What if something gets dirty from something airborne like exhaust fumes or atmospheric haze or something?
Am I able to wash that off?
If not, it's not self-cleaning, not even 'cleaning-neutral', but actively 'cleaning-resistant'.
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If the material is hydrophobic, and the dirt is not, then it wouldn't be self-cleaning, but it would work much better than what we have now.
Get some soapy water. Wash your car. Let it air dry. Do you see spots? That's the dirt that was mixed with the water droplets that were stuck to the surface of your car. If those droplets couldn't stick, they would have rolled off carrying the dirt with them.
Imagine you're lazy and never wash your car. The first time it rains, anything water soluble dissolves in th
Re:Can it be washed? (Score:4, Insightful)
Imagine you're lazy and never wash your car. The first time it rains, anything water soluble dissolves in the rain and rinses right off.
Unfortunately, there is an absolute shitload of non-water-soluble stuff stuck to cars, as a result of other cars which burn and/or leak oil.
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Good question. I wash all my teflon pans with a wet sponge - but stay away from scouring pads because they ruin the finish.
But they did say it retains its hydrophobia even after scratches. The mirrors on my car are waxed to keep water off - but dirt sure does build up. So I can see in the rain but not on muddy/salty days (yeah - that's a thing up North).
'course - this is just a proof-of-concept. It'll take "10 years" to bring it to market.
Wrinkly? (Score:2)
Aluminium scratch resistant? (Score:2)