coated fabric drying times

Hi Roman,
my guess, but not backed up by some scientific experimentation, would be that silicone coated fabrics have a faster drying time than PU coated fabrics (using identical fabrics, taking into account the weight of the coating, …). Reason for this is, if I'm not mistaken, that the silicone polymer is more hydrophobic than the PU-polymer and that often Pu-coated tent fabrics are only coated on the inside so that the outer face of nylon or polyester is able to absorb some moisture. Silicone coated fabrics are coated on both sides of the fabric (often is said that it looks more like a layer of silicone in which the textilefibers are swimming) so that the fabric in itself is less able to absorb moisture.
If you compare a silicone coated nylon with a silicone coated polyester, I guess the polyester sheet would perform better. Ofcourse, given the amount of available fabrics, coatingcompositions, coating thickness, … there are no definitive conclusions.

Now we only have to find a differntial equation which matches best the relationship between coating thickness and drying times :-)

Tom,

That is a good theory. My experince is the opposite, however, that the silnylon takes longer to dry. I am not very experimental with this, however. It's just the sense that I have and why I rarely carry a silnylon mid.

Basically, I get wet alot on my own trips and I have to constantly hang gear on bushes to dry it out. My sense is that the silnylon gear really never dries out as fast as the other stuff. I was looking to see if this was similar to any others' experience or not.

If a fabric coating were very hydrophobic, then water would not cling at all, but water will even cling to fat. Water clinging to fat albeit does so in a beaded up form. The beads of water have very small surface area to volume ratios and so may evaporate more slowly.

So I am wondering if the silnylon causes more beading — bigger beads — that take longer to dry?

….clearly the change in moisture (d wetness/d time) would be directly proportional to surface area to volume ratio……:D

That's an interesting thought Roman "more beading – bigger beads – that take longer to dry ?" I wonder whether the bigger beads mean that more water is removed by a good shaking. I have no idea whether this is true. Perhaps some of the more experimental members here with weighing equipment more sensitive than my wife's kitchen scales can test these two theories.