Would it be possible to put an anti-condensation coating on, say, an ice bag such that it will not get wet in use?

Question

I have seen anti-condensation coatings for glass, but as far as I know they're designed to cause any moisture that does form on them to sheet rather than bead. They do not, however, actually prevent condensation, and I don't see how any product could (other than extreme insulation, of course). The formation of condensation is an issue of physics; warm moist air meets cold surface and since cold air holds less moisture than warm, the moisture forms on the cold surface. On the other hand, engineers are pretty clever, so if there's a way to prevent this, it may be possible, even if I can't figure out how.

This question is actually prompted by some reviews of some ice packs I recently purchased from Amazon, in which reviewers complained about condensation, which seems like a nonsense complaint.

Sorry about the tag, but I tried "condensation," "dew," "moisture," "water," and maybe a couple of others and got no match.

Answer 1

The condensation mechanism of water vapor onto a chilled surface requires not only a chilled surface but also the presence of nucleation seed sites in the surface to kickstart the condensation kinetics.

Those nucleation seeds are sites on the surface (usually microscopic pores, crevices or specks of dust) which have a little water already trapped in them. The supersaturated vapor nearby "sees" that water and comes out of solution right there, adding to the amount of water originally present. Growing globs of condensed water then result, which can then freeze solid if conditions are right.

By coating a chilled surface with an extremely low-energy substance like a fluorosilicon oil or wax or a thin layer of a solid fluoropolymer, those surface sites are poisoned and no longer present themselves to the nearby water vapor as pre-existing bodies of condensate- and condensation is delayed or possibly eliminated altogether.

The problem with inhibiting condensation with low-energy coatings is that they eventually degrade and lose their effectiveness by accumulating dirt and grime. So a brand-new jacket made of Gore-Tex(tm) inhibits conndensation for a few months of wear but then supports condensation like anything else after it gets dusty & dirty.

Answer 2

Silicone coatings have been developed for these application, if I remember correctly , Exxeen Corp used to make an anti-fog silicone hard coat that might be useful to you.