Nanotech Coating Prevents Fogging

MilSF1 writes "MIT scientists have applied for a patent on a coating process that reduces or eliminates fogging on glass surfaces (car windshields, eyeglasses, etc). The new coating was described today at the 230th national meeting of the American Chemical Society."

The low tech solution

[Ckwop (707653)]

Ever wanted a shave in the shower but your hand-held mirror fogs up? Rather than buying this patented glass you can resort to a low-tech solution: Rub a little shaving foam over the glass and the wash the excess off so you have a thin, clear, greasy film on the glass.You'll find that the mirror no longer steams up.

The reason this works is because the greasy film causes much larger drops to coalesce on the mirror than you would normally get. These larger drops don't refract the light nearly and as a result are essentially transparent. This simple trick allows me to insure my sideburns are the same length even when under the most horrendous time presure.

See, who says that Physics can't be useful in everyday situations?

Simon

Re:The low tech solution

[dsginter (104154)]

If you've got a hand-held mirror, then you can just heat it up under the shower water. The "fog" appears on the mirror because it is lower temperature than the water vapor. When this water vapor comes in contact with the lower temp mirror, it loses the energy that it needs to stay in the form of vapor and turns back into water. This "fogs up" the mirror.

If you just heat up the mirror, then it will no longer suck the energy out of the water vapor and cause the fog.

Does Windows Vista use this?

[jkrise (535370)]

XP + Nanotech coating = Transparent Windows! Probly explains the long delay in releasing LongHorn...

Sorry

[FinestLittleSpace (719663)]

I won't believe any of this until there is a Podcast released on it.

Fog-X

[coke_scp (892822)]

The people who make rain-x, which works rather well itself to deflect rain, also make fog-x, which I've tested on a steamy bathroom mirror, and it works perfectly.

One drawback...

[bigtallmofo (695287)]

MIT scientists have applied for a patent on a coating process that reduces or eliminates fogging on glass surfaces. The new coating consists of a highly acidic chemical that melts the glass into a thick green goo. While the glass (now known as green goo) possesses none of its original qualities including transparency, it has also been shown to provide a 5% or greater resistance to fog.

Scuba Divers know a solution...

[se2schul (667721)]

...they simply spit in their masks to prevent fogging.

awsome

[Adult film producer (866485)]

One of the worst things about wearing glasses up north is the fogging.. being outside in -25c temperatures for even a few minutes and glasses get cold enough that they fog up when paying for gas, or shovelling snow, etc.. pain in the ass. I welcome this new technology :)

Great news for scuba

[vstanescu (522393)]

May be this will finally replace the old method of spit and rinse, because all those special glasses on the scuba masks had no effect until now. For those who don't know, if you want your scuba mask to be perfectly clean of fog, you have to spit inside it when it is dry, then rinse very fast with sea water (just to make the glass clear enough but probably without rinsing all the substances in the saliva from the glass) then put it on the face and dive immediately. For those who forgot doing this, even the best tempered glass became foggy in a few minutes in cold water.

Re:Great news for scuba

[oneandoneis2 (777721)]

Oh, come on, it's nowhere near *that* fussy!

You spit in it whether it's dry or not. Then you rub it into the glass with a finger, and give it as much of a dunking as you like in whatever water is around. Then it'll stay fog-free unless you allow it to dry out - so either put it on & trap the moisture in, or leave your mask laying flat with some water inside.

Of course even the best tempered glass will fog: tempering isn't supposed to provide anti-fog properties, it's used as a safety measure.

Lastly, it's not like you can't buy bottles of anti-fog from any half-decent dive shop that'll do at least as good a job.

(As a UK diver, I might add that one downside of spitting in your mask is that on very cold winter dives, your spit will freeze solid on the glass before you can do anything useful with it ;o)

1947 solution

[Spy Handler (822350)]

The X-1 had a bad problem with its windshield fogging up and frosting. On the flight before it went supersonic, according to "Yeager: Autobiography":

"My crew chief applied a coating of Drene Shampoo to the windshield. For some unknown reason it worked as an effective antifrost device, and we continued using it even after the government purchased a special chemical that cost eighteen bucks a bottle."

Re:1947 solution

[by Anonymous Coward]

Chuck Yeager has a lot of anecdotes about his crew chief. The guy was a genius when it came to common sense, solving problems, and getting things done. A true hero behind the scenes, the best there was.

If scientists and normal people would read this stuff, I am sure they would rediscover all sorts of solutions to common problems.

L8,
AC

So why is this being called nanotech?

[AltGrendel (175092)]

Basically, they take a glass/plastic mix of microscopic particles, coat the glass and then subject it to high heat, making a glass sponge (Very simplified explination).
I always think of nanotech as something more novel. If this were thousands of billions of tiny squeegee bulldozers one micron across moving the water to the edge of the glass, then I'd consider it nanotech.

Re:So why is this being called nanotech?

[qval (844544)]

It's being called nanotech because it uses nanoparticles, very small groupings of atoms, containing 100s or 1000s of atoms. Government money for nanotech research applies if you're working with objects smaller than 100nm in some dimension. IIRC, carbon nanotubes are sized roughly 5nm and larger in diameter.

The current state of the art of nanotech is not nanobots that can cure cancer. That's just what people speculate might come out of this technology, but how often is such exhuberance warranted? where's my flying car?

Also, by the way, something one micron across would be microtech by definition, not nanotech, but that's more me being a stickler than informative...

Re:So why is this being called nanotech?

[k98sven (324383)]

So why is anything being called nanotech?

Nanotech is a buzzword. It doesn't really mean anything. It's never meant anything. It's just a new word used by chemists, solid state physicists, and others to get funding and excitement around the same stuff they've been doing for quite some time.

Filing for patents?

[BadDoggie (145310)]

Funding for this study was provided by the Defense Advanced Research Projects Agency (DARPA) and the National Science Foundation (via the Materials Research Science and Engineering Centers, or MSREC)

I'm not a raging anti-patent looney screaming about the need for a free utopioan society, but if funding for this was provided by the public, surely the results belong to the public and the methods belong in the public domain rather than to MIT for the next 17-34 years.

woof.

Prior Art on this concept (links)

[snowwrestler (896305)]

An engineer named Richard Hartman developed antifog glasses for whitewater kayaking based on this concept several years ago. He developed a hydrophillic coating that was baked onto the lenses, and which prevented the formation of fog droplets. He even offered them for sale for a time--send him your prescription and he would send back a pair of glasses. I don't think he does that anymore.

Here [boatertalk.com] is a recent post describing his work.

Here [boatertalk.com] is a post from 2001 answering some questions about the glasses.

Here [boatertalk.com] is a search on the Boatertalk forum for most posts about it.

Re:Eyeglasses?

[bryhhh (317224)]

It's not just glass that fogs up though. Despite the /. story suggesting that this coating is only for glass, TFA says that this coating can be applied to "virtually any surface", which is great news for motorcyclists with plastic visors that always fog up on cold/wet days. Normally when it is raining, I have three choices,

1. Closed visor, it fogs up within minutes - Can't see a thing.
2. Visor fully open (nothing to fog), subjected to a face full of fast moving water droplets - can't see a thing.
3. Visor open slightly, air can circulate, visor doesn't fog, but water droplets form on the inside of the visor, which severely reduce visibility.

Re:Eyeglasses?

[cloudmaster (10662)]

They make an anti-fog product sold under the Rain-X brand (in a black bottle, generally). It doesn't work very well on glass, and is just as safe on plastic as steel wool. :)

FWIW, my full-face helmet has a little vent on the front below the mask, and a shield over my nose that keeps me from breathing right on it. The combination seems to work fairly well as long as I'm moving. It's a Bell Sprint, and I'm fairly happy with it (in combination with a mirrored face shield, for occasionally riding off into the sunset). Their website sucks - as you can't link directly to a product, it uses Flash, and they don't even list that they have different face shields - but most any non-Harley "powersports" shop I've been in carries their stuff.

Re:Eyeglasses?

[Vengeance (46019)]

According to TFA (not that I expect people to actually read the thing):

So far, the coating is more durable on glass than plastic surfaces, but Rubner and his associates are currently working on processes to optimize the effectiveness of the coating for all surfaces. More testing is needed, they say.

Re:I wonder...

[b100dian (771163)]

I guess not.
Humidity is still there - just not in the form of little droplets.

Re:More light?!? Yes, it does.

[G4from128k (686170)]

Their claim is valid. Anytime light passes through an abrupt change in the index of refraction (e.g., from air to glass), a percentage of the light it reflected back. That's why you see a ghost image of yourself in even "transparent" pieces of glass. On ordinary glass, about 4% of the light is reflected (removed) by each air-to-glass or glass-to-air interface (8% for each pane).

Adding a anti-reflective coating that has an intermediate index of refraction can reduce this. Nonlinearities in the reflection process mean that two interfaces of lesser change reflect far less than one big change. Camera lens makers do this all the time because many lens have 6 to 20 pieces of glass and thus a dozen or more interfaces that each would to attenuate light and create multiple internal reflections between the lens elements.

It may not be much, but that antifog coating probably lets a couple extra percent of the light through.

Re:More light?!?

[DoubleMark (911283)]

Speaking as an MIT student working on this project, yes it lets more light through- a lot. Uncoated silica reflects about 8% of incident light, as was posted elsewhere. With our coating, this drops below one percent through most of the visible spectrum, and below .2% at a peak wavelength dependent on the number of coating layers (around 550nm for a 14-bilayer coating). It's a pretty nice improvement- you can place a half-coated slide against white paper and the untreated side looks dirty by comparison. I can try to dig up the spectrophotometer measurements I took a few weeks ago, if anyone cares that much.

Also: Whoa, Rubner got /.ed. Party in lab today!

Re:I'm blind!

[wbren (682133)]

I'm blind, you insensitive clod!

But at least you're a wonderful touch typist.

Re:Solve a Real Problem

[hcdejong (561314)]

Which reminds me: we need a coating for monitors that prevents greasy smudges from morons pointing at the screen. A thin metallic film with a 10 kV feed would be good.