Here's kinda how eVent works different:
A PTFE (eVent and gore), in its natural state, is readily contaminated with oils from our body and other environmental substances. The oil contamination eliminates the hydrophobic quality and the fabrics leak.
To solve this, some manufacturers (gore)put a layer of polyurethane (PU) over the PTFE membrane to protect it from contamination. The PU is hydrophilic; it absorbs water. First, sweat is condensed and absorbed into the PU layer on the inside of the fabric. Because PU absorbs and retains sweat, the inside of the fabric becomes wet. Then, body heat begins to push that dampness through to the outside of the fabric where it can finally evaporate - a very inefficient process. This combination “breathes” but not nearly as efficiently as the PTFE membrane alone.
Voila! Along comes eVent fabrics. They have developed a way to make oleophobic (oil repelling) while still retaining the hydrophobic (water repelling) characteristics of PTFE. It keeps outside water out and lets the inside sweat pass right through it. Where Gore and others collect it and NOT let it pass through through direct venting.
Now we have a material,eVent, that is very waterproof, combined with one of the highest breathability ratings of any WP/B fabric! Tests run at the US Army’s Soldier Systems Center, in Natick, Massachusetts, put eVent fabric at the very top of over a dozen fabrics sampled.
eVENT Fabric is an ePTFE film that has been rendered oil-repellant, and thereby free from body-oil contamination, via a method that retains both the inherent open-pore structure of the membrane as well as its hydrophobic properties.
eVent does not add a second layer of Polyurethane like Goretex. eVent Teflon membrane is treated through a propritary (patented) process of coating the ACTUAL INDIVIDUAL MICROSCOPIC FIBERS WITHIN THE MEMBRANE to prevent contamination by skin oils or sunscreen. This propriatary coating does not inhibit vapor passage away from the garment wearer like the polyurethane coating that Goretex uses.
......i totally copy and pasted this off the internet. It was way to much to type much less what you have now read!
