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Different types of self-cleaning materials that incorporate nanoparticles have been developed in the past. Stain-repellant fabrics and paints that are currently on the market typically have a nanoparticle or nanofiber coating that causes drops of liquid to roll off instead of getting absorbed into the material. The liquid drops take small particles of dirt and grime with them.
More materials are in the research stage. These include microstructured, Teflon-like materials that bounce oil off their surface. (See "No More Thumbprints.") Purdue's Youngblood has made a material that changes its structure depending on whether it's in contact with oil or water, causing water to spread out into a thin film and oil to bead up so that it runs off or is easily wiped off with water. (See "Self-Cleaning, Fog-Free Windshields.")
All of these materials are based on making the surface oil or water repellant, says Youngblood. This is a concept that is completely different from that of the new titanium dioxide coating. "We're controlling wettability and surface interaction," he says. Titanium dioxide coatings, on the other hand, degrade organic matter. "It has nothing to do with surface wettability whatsoever. Here, you're not removing what's on the surface: you're burning it off."
Each of these techniques to make self-cleaning materials has its own limitations. Superhydrophobic materials, which repel water, are typically good at removing dirt particles but "don't deal with oils well," Youngblood says. Materials that repel oil, such as the one that he has developed, might not work with certain types of oil. The titanium-dioxide-coated materials, on the other hand, will not work unless they are exposed to sunlight for hours.
The sunlight requirement has not stopped the technology from getting commercial interest. Several wool manufacturers have suggested that they'd like to evaluate the technology, Daoud says. He expects self-cleaning wools to be available in the market within two years, once sufficient laboratory and industrial trials have been completed.
Fabrics woven from highly conductive, nanotube-coated cotton are wearable biosensors.
New chemistry and microsurfaces have led to super oil-repellent materials that are self-cleaning.
A new adaptive polymer coating combines unusual chemical properties to help maintain a clear view.
If the price is competitive, this would make it easier to keep baby clothes clean. Food and drink of all sorts tend to find their way repeated only their clothes. As a parent, the baby also reaches out and touches the parents clothes too. Pants and shirts that automatically recover from this interaction at a reasonable price are a really good development. This could save some money on dry-cleaning.
Manufacturing in the United States is in trouble. That's bad news not just for the country's economy but for the future of innovation.
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gabrielg01
450 Comments
Harmless?...
The chemistry behind this is that highly reactive radicals are released, which oxidize pretty much everything they come in contact with. Yet the authors point out that this is "harmless to skin"...Oh really???!!!...
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gonk
1 Comment
Re: Harmless?...
If the coating were harmful to skin, it would also destroy the wool fibers. Wool, skin, fingernails and hair are all composed of the protein keratin (as mentioned). Furthermore, given the presence of titanium dioxide in products applied directly to the skin (cosmetics) it is likely that we'd already know if it was going to start oxidizing people's skin, since their lips would have burned off.
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incognito
1 Comment
Re: Harmless?...
While it is surely true that nanotechnology can achieve what initially appear as miraculous results, it is also the case that this still infant science has the potential for creating longer term unexpected, unanticipated and potentially life threatening consequences. As in all cases of new developments, the originators take umbrage at any suggestion that their brain child is less than perfect. I believe that this is an exceedingly dangerous attitude.
Manmade nanoparticles can enter an animal body via ingestion, aspiration or absorbtion. Once these particles have been incorporated into any animal tissue the ensuing results of these tiny particles and their ability to go where no particle has previously gone before, presents us with an astounding array of possibilities as regards the subsequent effects on other body constituents. It is the height of folly to assume that a nanoparticle will do only as hoped by a given researcher and will not subsequently migrate elsewhere and do damage that is stunning in its implications for potential biochemical and physiological injury.
I am not anti-nanotechnology; I simply urge great caution. Newsworthy events keep reminding us that the unexpected, even in allegedly fail-safe technologies, often create nightmare scenarios whose after effects can plague us for generations to come.
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