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Simple Method Yields A Wrinkly, Durable, Water-Repellent Coating (acs.org)
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.
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Teflon is not PFOA. Teflon is PTFE. PFOA is used during the creation of PTFE, but is completely burned off during PTFE manufacturing, leaving no PFOA. Of course, lots of toxic things are used during the manufacturing of safe things all the time - that stainless steel staple used to hold your surgery together, or your frying pan/cooking utensils contains chromium, a nice and toxic heavy metal.
Browsing at +1 - no ACs, I ignore their posts. So refreshing!
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.
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.
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.
> 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.
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.
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. Heaven has 360 degrees. 60 minutes in one degree. 1 minute of arc
on the surface of the earth is 6000 feet. 6 ft per fathom. Thus a nautical mile is 1000 fathoms. Then
the damn scientists got into it and said a nautical mile = 6079.7 feet, and fucked it all up. They could
have changed the foot, or the meter, etc. but no.
The final straw was the digital calculator in place of the balance scale. Now nobody remembers why ...
we have 16 ounces to a pound (answer, divide by two on a balance scale: 16,8,4,2,1). Try that
with a kilogram
Napoleon lost his bid for world domination at Waterloo and St. Helena. They should have buried his
meter with his sorry ass arsenicated body.
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:
"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.
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.
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"