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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.
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.