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Black Silicon Slices and Dices Bacteria
Zothecula writes "Originally discovered by accident in the 1980s, black silicon is silicon with a surface that has been modified to feature nanoscale spike structures which give the material very low reflectivity. Researchers have now found that these spikes can also destroy a wide range of bacteria, potentially paving the way for a new generation of antibacterial surfaces."
Does this stuff have any sort of neat catalytic effects or other cleaning mechanisms, or are the structures so tiny that bacterial polysaccharide goop won't neutralize them inside a week?
Can I get this for my car, to absorb radar and lidar?
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"This structure generates a mechanical bacteria killing effect which is unrelated to the chemical composition of the surface," says Professor Crawford, who is Dean of the Faculty of Life and Social Sciences at Swinburne.
Very low level abrasive... I wonder if and how that might serve as a soap.
As it wears down or chips away over time, can the nano particle surface become airborne and become inhaled having similar issues like asbestos?
Soap also serves as a pretty good soap. I suspect the fine size scale of these structures, on a rigid silicon backing, would't be too good at reaching into very much of the rugged mountainous topography (on a bacteria's scale) of human skin.
From the TFA:
" ... the wings of the cicada Psaltoda claripennis could shred certain types of rod-shaped bacteria ... "
... the wings of the Diplacodes bipunctata or Wandering Percher dragonfly were even more deadly, killing both rod-shaped and spherical bacteria ... "
"
I am very curious.
Since the structures on the WINGS of the insects, do they have some yet-to-be-discovered aero-dynamic functionality, apart from their ability to shred bacteria ?
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Good point, skin would have massive peaks and valleys to scale. Perhaps a fluid medium then, streamed over a sufficiently long, inclined surface.
Except this only works on the bacteria on contact.
Get a bit of slime and the surface never touches most of the bacteria.
"It slices!, it dices! and chops and grinds for all your bacteria processing needs! No more fuss and muss! No more missing mitochondria! And all this can be yours for 4 low monthly payments of just $39.99! It's a limited offer, so get yours nooowwww!"
Table-ized A.I.
Can this structure of silicon also be used for other things?
Such as battery anode? Massive surface area would be highly useful.
Inside solid caps? Letting us shrink caps even smaller and still keep the same values.
How about solar cells? Something that provides very low light back is absorbing all it can. And massive surface area would be useful.
This sounds like some cutting edge (bon mot premeditated) technology, but I swear my brain saw Blacon Slices on the first skim.
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What you are describing sounds like a waterslide. ;)
A long waterslide flowing with an abrasive grit slurry, however, might not be the most fun kind of waterslide.
Sounds like a treatment for hemorrhoids.
If you are thinking hemorrhoids, I think your more likely shape is a dildo, rather than a long waterslide. Not sure if it'll work, but you can probably easily sell the test footage.
Durability of an exotic surface structure can be a problem. An example is ultra-hydrophobic coatings. (Now available at retail as Rust-Oleum NeverWet.) They really do repel liquids so thoroughly that coated surfaces can't even get muddy. But they seem to wear out quickly. There are YouTube videos showing that stuff working for ten minutes, then failing. But maybe someone will come up with an improved coating that's tougher.
"Paint-on solar cells" also fall into this category.
I imagine that that's why those bugs are getting away with them. Nothing like being biological to get aggressive self-repair capabilities thrown in more or less for free... Pending nanites, no such luck on our end.
Marine anti-fouling coatings have similar trouble: they've tried to make less toxic ones, with specially crafted surface geometry that resists mooring by marine organisms; but the minute it starts to wear out, boom, stuff growing. Even the ones that are laced with ghastly organometallic biocides eventually leach enough to lose effectiveness and have to be stripped and re-applied.
(though, speaking of anti-fouling coatings, if microspike-structures are aerodynamic enough for insect wings and brutally biocidal, I suspect that the world's marine shipping industry would fight like dogs to give you their money if you could paint this stuff on...)
the world's marine shipping industry would fight like dogs to give you their money if you could paint this stuff on...
There's two ways to do it:
1. http://en.wikipedia.org/wiki/Reactive_ion_etching
2. Pulsed lasers
AFAIK, this only works on silicon, which doesn't strike me as something that's durable enough for marine applications.
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Was reading about that the other day, the nano-spikes act to break up water droplets into smaller droplets allowing them to bounce off the surface more easily. The same principle also allows the droplets to slide off the surface more easily, useful for boats and planes. Shark skin has similar nano-scale surface geometry, allowing the shark to move faster with less energy. With dragonflies it's apparently the network of ultra-fine capillaries on the wings that does the same job as the spikes.
As you say if it could be made as a durable paint all sorts of industries will be beating your door down to throw money at you, even the plumbing industry would be interested since they have problems with bacterial slime coating the inside of pipes, slime that even chlorine will not shift.
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I suspect that I don't even want to know how many 400mm wafers it takes to cover a container ship...
Even when they're not used for cleaning hands materials like this are useful for keeping surfaces cleaner to reduce germ transmission. I've read that simple brass and other copper alloys also have similar properties and there was a brief campaign to use it for things such as door handles in hospitals. Brass would most likely be much more economical to produce and has the added benefit of being very easy to recycle.
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I wish the best of luck to whoever gets to model the behavior of a mixed (mostly) nonpolar gas interacting with a dense, more or less randomly packed, array of 240nm spikes, composed of some sort of complex biological polymer arrangement, at the boundary of the (already complex enough) interaction between an insect wing and the surrounding fluid.
Let us suppose a perfectly spherical spike in a vacuum...
Set your phasers on "funky"!
Fix nano-scale silicon bayonets!
How is this different from D.E. ?
Like, after 250nm it's zero and can't do much to the atmosphere at that distance and beyond. Which is where most of that atmosphere is.
So although it's a high potential gradient, it can't produce much force because it can't act on much mass to produce that force.
A nanoscale wing that can hold *itself* aloft would be moderately easy.
Attaching a macro-scale body to that of even a small fraction of a gramme would be a different kettle of fish.
It would be interesting to see how this measures up with the bacteriostatic characteristics of copper and brass.
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Plus, bugs don't live very long. If you only need your ship to work for a couple of weeks, there's a lot you can get away with too.
weinersmith
I suspect that I don't even want to know how many 400mm wafers it takes to cover a container ship...
Lots, but silicon is cheap as sand. Provided that you don't need chip-grade silicon for your ship . . .
Biore is a popular Japanese liquid body soap made of iirc micron scale nylon beads like those
used to calibrate electron microscopes but big enough to enter pores but not penetrate flesh,
which is what your shards might do and give you asbestosis.
You fight wearing out by making internal structure such that it sheds in layers which reveal new surface-like layers beneath them as they fall off. For that, you need to design connection points between layers to most probably fail (to be weakened) first. Like a bed of sharp nails connected by its fine points to another bed of nails above, and that one with another one above it ... etc.