What is Gore-Tex? The ePTFE membrane, how it works and the switch away from PFAS

Gore-Tex is W. L. Gore & Associates' trade name for a waterproof, breathable membrane, first made in 1969. Its pores are small enough to block liquid water and large enough to let water vapor out. The original membrane is expanded PTFE, a PFAS chemical, and Gore says its Next Gen products now use a membrane made without intentionally added PFAS.

How the membrane works

Gore-Tex is not a single fabric but a thin membrane laminated to outer textiles. Wikipedia says the material is expanded PTFE (ePTFE), a stretched form of polytetrafluoroethylene. In 1969, Bob Gore stretched heated PTFE rods with a sudden, accelerating yank instead of slowly. The solid stretched about 800% into a microporous structure that was about 70% air.

The result has long, narrow fibrils connected at nodes. Wikipedia says ePTFE can be made permeable to certain vapors and gases but is impermeable to most liquids, including water, which is the property raincoats use. Before Gore-Tex, it explains, simple rainwear was a two-layer sandwich of woven nylon or polyester and an inner polyurethane layer that gave water resistance but little breathability. Early Gore-Tex replaced that inner layer with a porous fluoropolymer membrane.

A trademark, not the only option

Gore-Tex is a brand, and brand and technology are separate things. Wikipedia says Gore's patents on ePTFE-based fabric expired in 1997 and membrane waterproof fabrics are now available from other brands. So "waterproof and breathable" on a tag does not mean Gore-Tex. Gore says its products now appear in jackets, footwear, gloves, hats and accessories, plus professional workwear lines for rescue services, defense and law enforcement, so the name covers many constructions rather than one fabric.

Gore's own heritage timeline shows how the line grew. W. L. Gore & Associates was founded in 1958 by Bill and Vieve Gore in Newark, Delaware. The 1969 discovery launched the brand, GORE-SEAM sealing machines and tape followed in 1979, and in 1981 spacesuits made with Gore fibers supported NASA's first Space Shuttle mission. The "Guaranteed to keep you dry" promise arrived in 1989, GORE-TEX PRO garments in 2006 and Next Gen products in 2022. Wikipedia adds that outdoor brand Marmot was one of the first adopters in 1976, starting with a waterproof sleeping bag. We did not verify any of the company's performance claims independently.

The PFAS question

PFAS are, in the words of the U.S. Environmental Protection Agency, "widely used, long lasting chemicals, components of which break down very slowly over time." The EPA adds that scientific studies have shown exposure to some PFAS in the environment may be linked to harmful health effects in humans and animals.

Wikipedia says PTFE is made with an emulsion process that used the fluorosurfactant PFOA, a persistent environmental contaminant that the International Agency for Research on Cancer has classified as carcinogenic to humans. It says Gore pledged in 2017 to eliminate PFCs such as PFOA by 2023, although the core technology would remain based on PTFE, itself a PFAS compound. The entry also says many Gore-Tex products carry a durable water repellent coating, and that versions without PFCs of environmental concern are marketed as "Gore PFC EC Free DWR," which lacks oil repellency.

Wikipedia further notes that two lawsuits were filed in 2023, and a state lawsuit in December 2024, over PFAS pollution around Gore's Cecil County, Maryland manufacturing plants. Those are allegations; we did not review the filings or any response from the company.

The switch to ePE

Gore's current About page says the company has redoubled its efforts to develop more sustainable textile solutions with Next Gen GORE-TEX Products, which "offer durable performance, are PFAS free* and have a reduced carbon footprint**." The asterisk reads: "Made without intentionally added per- and polyfluorinated substances; may contain trace amounts." The second note says the carbon claim is measured through laminates with a new lower-mass membrane and select textiles, per the Higg MSI.

The Next Gen products use an expanded polyethylene (ePE) membrane, introduced in 2022 by the company's timeline. Wikipedia says that from 2024 Gore is replacing ePTFE with ePE in consumer fabrics, and that the new material is intended to perform comparably but will cost more and require more frequent washing. That last point comes from Wikipedia and is not a Gore statement, so test it against the care tag.

For the claim-checking side, see our guide to greenwashing rules in fashion, which explains why a footnoted "free" claim deserves a close read. The outer fabric also matters; our explainer on polyester fabric covers a common face material.

What to check on a tag

Look at the product line, because "Gore-Tex" now covers more than one membrane. Ask whether a jacket uses the original ePTFE or the Next Gen ePE. Check what water-repellent finish the maker uses and what chemistry it says that finish is, since Wikipedia notes many Gore-Tex products carry one. Gore's materials describe a quality system that includes testing and certified factories, but we did not audit one.

Our take

The core idea is sound and 57 years old: a thin membrane that blocks water and lets vapor out. The new part is the chemistry. We would buy a Next Gen jacket if you want to avoid PTFE and accept a company-stated claim with a trace-amount caveat. We would skip paying extra for "PFAS free" without checking the label, and we would watch for independent testing and for the court cases to resolve.