The heart of each GORE-TEX product is the GORE-TEX membrane
The GORE-TEX membrane is an extremely thin layer of expanded polytetrafluoroethylene (ePTFE). It has over 1,5 billion pores per square centimeter. It’s these pores that give the GORE-TEX fabric its characteristics.
The microscopic pores of the membrane are 20,000 times smaller than a water droplet, which means that no rain can penetrate it. This is what makes the GORE-TEX membrane waterproof.
The pores are 700 times larger than a water vapor molecule which means perspiration passes right through. This is what makes the GORE-TEX membrane breathable.
The membrane’s structure is similar to that of a hedge. The wind is caught up entirely in the branching and thus averted from the body. This is what makes the GORE-TEX membrane windproof.
Windproofnes of GORE-TEX and WINDSTOPPER® membranes are of utmost importance for protecting the body from so-called ” Wind-chill ” effect – body cooling caused by the wind.