Nanotech Coating Prevents Fogging 201
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 (Score:5, Informative)
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
Fog-X (Score:5, Informative)
Re:Eyeglasses? (Score:4, Informative)
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:More light?!? (Score:2, Informative)
More light than comes from through the glass??
if it makes a smoother surface, it could allow more light through
Scuba Divers know a solution... (Score:4, Informative)
Great news for scuba (Score:5, Informative)
Re:More light?!? (Score:2, Informative)
Because most of the light that does not pass through the glass is not "absorbed" inside the the glass but instead reflected at the air/glass and glass/air boundary layers.
Coating glass with stuff to minimize the reflection is a really old thing. Ever wonder why the lenses of (good) binoculars seem have a bluish or reddish tint to them ? Because they're coated to increase light transmission.
Re:More light?!? Yes, it does. (Score:5, Informative)
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:The low tech solution (Score:5, Informative)
If you just heat up the mirror, then it will no longer suck the energy out of the water vapor and cause the fog.
Re:Fog-X (Score:2, Informative)
As a result, the droplets flatten and merge into a uniform, transparent sheet rather than forming countless individual light-scattering spheres.
Re:Eyeglasses? (Score:5, Informative)
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:The low tech solution (Score:3, Informative)
I can't recall where I heard this, but some Japaneese hotel rooms feed the hot water for the shower through a miniature radiator behind the mirror. This way, running the shower automatically heats the mirror so that it doesn't fog.
Re:Great news for scuba (Score:4, Informative)
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)
Re:Eyeglasses? (Score:2, Informative)
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Re:More light?!? (Score:4, Informative)
Also: Whoa, Rubner got
Get a Fog City Hyper Optiks faceshield insert (Score:3, Informative)
These things are sweet. They don't fog, period, and if you get the UV reactive one, it darkens in sunlight so you don't need to carry two shields. It's not quite as dark a real reflective shield, but it's dark enough.
Re:1947 solution (Score:4, Informative)
If scientists and normal people would read this stuff, I am sure they would rediscover all sorts of solutions to common problems.
L8,
AC
Not just motorcyle helmets (Score:2, Informative)