Re: Is there such a material?

Hi Brett,

Good question!  I haven't been able to find any commercially available 
waterproofings that thin, so if you've got one, you can probably make a 
lot of money...

First off, I'm assuming you mean "completely waterproof" as being totally 
protected against ingress of water while continuously immersed.  The 
British Standards Institution (BSI) has a specification BS EN 
60529:1992 that is used to rate the... um... waterproofedness of an 
object.  The highest rating, IPX8, means that it can withstand a 30 minute 
immersion under 33 feet (~2 ATM) of water without leaking.  

There were no films that were as thin as sub-micron that were waterproof.  
The smallest I found was GORE-TEX which 
was only available at 1.5 mil (38 microns).  Films of rubbers or plastics 
were thicker than that.  Bear in mind that most films run on the order of 
50 micron or larger, just to have enough structural strength to hold 
together.

An alternative to a separate layer would be a coating on the bag that 
would provide waterproofing qualities.  There has been progress in plasma 
deposited layers of Teflon, but this 
has been 
primarily for  
Friction Resistance and  
Dielectric Properties.  They can grow layers as thin as you want them, 
but the real trick would be to get one thin enough to be sub-micron, but 
thick enough to be waterproof.  Then you've got to deal with the thickness 
of the substrate layer you were depositing the teflon onto, so it's a 
tough objective.

So while there's nothing out there right now that's waterproof and sub-
micron, that certainly doesn't mean it can't be done.

Hope this helps!

Jeff Yap
Mad Scientist

Waterproof bags:
GPS International
Aquapac International