GORE-TEX is an amazing breathable, waterproof textile found in clothing involving hiking, mountaineering, etc. making it a high-performance material. We as consumers have seen Nylon in several avatars, the highlight being it doesn’t let Ultraviolet rays pass through. But then, nylon does not let water vapor pass through it either. This means nylon waterproof clothing traps sweat, so that after a while the inside of the clothing becomes wet, making it unpleasant to wear. Gore-Tex® on the other hand has the desirable properties of nylon, but is also ‘breathable’. Unlike ordinary synthetic textiles like nylon, GORE-TEX uses a membrane that stops rain from getting in but lets perspiration out. So it keeps you dry on the outside and dry on the inside at the same time. Over a period of time, the material has been used extensively in jackets, coats, outerwear, bivy bags, backpacks, boots, and even sneakers. But what exactly is Gore-Tex and how does it do what it does? Read on.
In October 1969, Dr. Robert “Bob” W. Gore discovered how to turn PTFE (Polytetrafluoroethylene) into a micro-porous material called expanded polytetrafluoroethylene (ePTFE), which constitutes the waterproof and breathable membrane used in GORE-TEX. It’s this ePTFE membrane that revolutionized the reputation of W.L. Gore & Associates, a company started by Bob’s father Wilbert Lee “Bill” Gore who worked at DuPont as a chemical engineer before starting W.L.Gore & Associates from his basement in 1957.
But how can water flow through your clothes in only one direction? Thanks to the ingenuity of GORE-TEX, it’s much more than just one simple material. It’s more like a sandwich of three layers. There are two layers of nylon making up the “bread” slices and then a layer of micro-porous Teflon® (aka polytetrafluoroethylene or PTFE) in between. Teflon’s slippery nature makes it great for waterproofing things which is why famous buildings, including the Millennium Dome in London, are even made with gigantic Teflon roofs. In short, the Teflon’s there to keep out the rain. So the next time you wish to rock your sneakers but the weather plays the spoil sport, just slip into your gore-tex gear and you should be fine.
Gore-Tex® contains layers of nylon, PTFE and polyurethane. The PTFE contains a lot of tiny holes called pores ranging as high as 14 million per square millimeter. Each one is too small for water droplets to pass through, but big enough to let water molecules from sweat go through. Without the nylon, the layers would be too fragile to be useful so Nylon still plays a useful role in holding the sandwich together.
GORE-TEX clothes are generally made from three layers: a conventional outer fabric, plus two separate GORE-TEX layers with similar but quite different waterproof-breathable properties. On the inside, there’s a thin, relatively delicate inner membrane or film that’s hydrophilic (water-tolerant), which readily allows water vapor to escape but doesn’t allow liquid water in. The hydrophilic layer absorbs perspiration produced by your body and transports it, by diffusion, to the outside. Next to the inner layer, there’s a thicker outer layer made from a micro-porous plastic polymer, such as Teflon. This layer is hydrophobic (water-resistant), which means it resists water from outside, even when it’s impacting at high speed or pressure (as in heavy rain) or when the fabric is flexing back and forth while walking or running. The hydrophobic layer doesn’t soak up water coming in from the outside as droplets simply “bead” on its surface and stay there, without soaking in. But like the inner hydrophilic layer, it does allow perspiration to escape from the inside by diffusion. Magical, isn’t it?
Due to these properties, Gore-Tex is therefore a slightly expensive option. But imagine all the money you’re going to spend on water repelling solutions for your sneakers, jackets, hats and bags. In the long run, these costs will add-up and amount to much more than say a Gore-Tex Parka. Gore-Tex is therefore a good investment for the rainy season and even cold weather for the aforementioned merits.
Are you going to invest in Gore-Tex this monsoon season? What are some other materials you like as far as waterproofing goes? Let me know in the comments section below or hit me up on Instagram.