material that sheds water like RAIN-X?

I seek a material that sheds water really well.
Transparent/translucent would be extra points, but it's not required.
Is teflon the best? I think it's available as a foil.

try a hot teflon surface - a common kitchen pan at 250C will work.

Hi, Alan,
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FEP is even better (Fluorinated Ethylene-Propylene copolymer). It's just about as water repellant as PTFE, but it's a thermoplastic, and so the optical quality of thin films of it is much better than those of PTFE. It's obtainable in sheets down to 25 um thick. Goodfellow charge an arm and a leg, but I have bought some gift-wrap, not outrageously expensive, which appears to be FEP and is 40 um thick.
Cheers,
Zigoteau.

Zigoteau wrote:
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PTFE is a thermoplastic as well.
Michael Dahms
f'up2 sci.mat

Hi, Michael,
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Chapter and verse, please.
I would rather trust http://www.teflon.com/Teflon/downloads/pdf/e89757-3.pdf?GXHC_gx_session_id_=GXLiteSessionID-8376216848983060641
The PTFE we know and love, polytetrafluoroethene with no hydrogen in its composition at all and little main-chain branching, is not a thermoplastic. Blocks of PTFE are formed by sintering the powder at temperatures close to the decomposition temperature. That's why PTFE is never transparent. I don't quite understand how they manage to make it in 10-um thin sheets, but even that is translucent rather than transparent, it is full of microcracks and cavities, and its mechanical properties are not brilliant.
Cheers,
Zigoteau.

Zigoteau wrote:
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Look for the molecular structure!
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The above sentence shows that FTFE is a thermoplastic. Duroplastics cannot be sintered.
Michael Dahms

Hi, Michael,
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Well, Wikipedia backs you up. I had thought that a thermoplastic had to melt outright. They have gone and changed the definition while my back was turned. Well, FEP does melt before it decomposes, and thin films of it have better optical and mechanical properties than PTFE as a result.
Cheers,
Zigoteau.

Silicone spray, there are a couple different types. Polydimethylsiloxane will not form a dry film by itself. But you can get spray-on stuff that will form a dry film, probably from www.mcmastercarr.com or www.freemansupply.com and I think that these guys also carry it www.synair.com
Treating a substrate to polydimethylsiloxane fluid would probably work temporarily. It's just silicone spray on lube, but wont form a dry film.
It all depends on your substrate.
Dissolving some parrafin in fuel oil makes a great release agent for concrete and the parrafin is extremely hydrophobic. But soy wax is vary slightly water soluble.
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Lefty wrote:
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Lefty,
For glass silicone spray rubbed dry works very well to make glass shed water and dust both. Every day when we started up and just before sundown if we were working at night and we did most nights we would clean all the glass squeaky clean a spray on silicone and rub it dry with paper towels and for at least 4 or 5 hours if dust stuck to the windows you could hit and it would fall off. If it got real dry add a rub down with fabric softener before the silicone to help dissipate the static charge.
Gordon Couger Stillwater, OK www.couger.com/gcouger

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will
Great looking photos of diatoms. Gotta love em.
You might want to take a look at this http://www.govliquidation.com/index.html
They are always selling high end microscopes & related gear.

Alan,
Could you give us some details on the application? Do you require a coating or a separate sheet/film? Do you want the material in bulk? If you're only interested in a coating with water-repellant properties, RAIN-X or another automotive wax would work just fine, as long as it could adhere to your substrate.