CO2 permeable membrane

Hello
a manufacturer of such foils is www.sarnafil.ch

Liquid water and dirt will settle out in the chamber, but if suspended in the air/gas in will be in the form of an aerosol.

It sounds as though you need a high performance coaslescing filter. Most compressed air filter makers can supply them.

Like the stomata on the underside of a leaf?

I am looking for a similar material that will not allow water vapor to pass but will allow 4 angstrom or less gases to pass. Please advise if you find a source.

Van

http://www.liquidboot.com/gv/projectlist.php

This Company is Liquid Boot and they have a variety of possible products and protection levels available. They are very popular in the LA area with a lot of ground water.

I'm no chemist but to protect a pressure transducer from moisture I used a medical hydraphobic filter in line...

I think it was a Sartorious made one in a disposable plastic case, so it was nice and cheap. Also, I think it had a filter size of less than one micron and being made out of polypropolene(??) it was naturally water resistant...

I showed the guy just how good it was by sticking it on a half full syringe and squeezing through the air until the water hit the filter and the syringe just wouldn't push any further...

Look for syringe filters, there are masses of them and cheap, some are hydrophobic to stop water or microbe / bacteria contamination of a drug as its being syringed out of a bottle etc...

John.