My technical clothing always dries much quicker than normal clothes – some of my tops feel almost dry coming out of the washing machine.
Thats because they repell water.
Sweat on your skin vapourises, the water vapour then travels through the fabric to the other side, as it’s more diuted on the outside it doesn’t come back in again, thus you stay dry. The trick is in making an outer layer that allows the vapour (sweat) through but not liquid (rain), whilst the skintight baselayers job is to increace the surface area for sweat to evaporate from (both by being fibrous and by encourageing sewat to form patches which evaporate cooling you down rather than droplets which run off and are of no use). Any intermediate layers are to trap air from circulateing, but not trap it so much that water vapour can’t diffuse through it.
Basic thermodynamics:
0th law – the temperature is trying to reach equilibrium
1st law, Enthalpy – evaporating sweat requires energy
2nd law, Entropy – evaporating sweat leads to greater dissorder (mass and energey diluted through the system).
3rd law’s inrelevent AFAIK.