How do waterproof/breathable rain jackets work?

[Zone-5]

How do waterproof/breathable rain jackets work?

The best full description I have ever found!

http://www.rei.com/learn/expert-advice/ ... works.html

How do waterproof/breathable rain jackets work?
Which is best: Gore-Tex? eVent?
A laminate or a coating?
Which is more breathable and comfortable?

These are basic rainwear questions that often require technical answers.
We'll do our best to provide explanations in language that non-scientists and non-engineers can comprehend.

[gedanate]

Gore-Tex is the original as far as I know. But there are various copies now.

The material stops liquid water from entering your clothing, but it allows waver vapor (i.e. gas, steam) to escape your warm body. That's the "breathable" bit.

Very clever stuff. Goretex (and its copies) keep you comfortable where traditional rainwear makes you hot and sweaty. Often it seems wetter inside from all that trapped sweat from non-breathable waterproof clothing, including rubber, plastic and even oilskin macs and ponchos.

[wayno]

all the figures are generated in the laboratory, when its bucketing down in the real world, it all becomes academic and any advantage one membrane has over another gets nullified a., worry about the physical venting instead.

[Zone-5]

...when its bucketing down in the real world, it all becomes academic...

Yes I agree and why I always carry a small umbrella! It just beats a coat and hat hands down.

...worry about the physical venting instead.

Yes, I have always been a fan of a vest for this reason of venting as sweatiness has not usually a problem when the garment has no arms. Rain wet arms I can deal with but body sweating... no!