The accidental discovery of “ePTFE”

News and Adventure from Glacier National Park

The following is an adaptation from Ramble On: A History of Hiking:

While working for his father’s start-up company in Delaware, Bob Gore accidentally discovered a new polymer known as expanded polytetrafluoroethylene, or ePTFE, which would eventually become a crucial component in a wide range of outdoor gear and apparel products.

Polytetrafluoroethylene (PTFE), also known as Teflon, was originally discovered by a DuPont scientist in 1938. Convinced that there were many other opportunities yet to be discovered, Bob’s father, Bill, left DuPont in 1958 to pursue other applications for the new polymer. In 1969, in a bit of frustration while trying to make the polymer more efficient, Bob gave a swift yank to a heated rod of PTFE that unexpectedly caused it to stretch by almost 800%. This transformed the solid PTFE into a super-thin microporous sheet that was now roughly 70% air. Consequently, the expanded polytetrafluoroethylene, or ePTFE, was also discovered to have billions of micropores that were 20,000 times smaller than a droplet of water. As a result, Gore would eventually come to realize that the new product could block rain if it were applied to a fabric. Additionally, since the micropores were still 700 times larger than a water vapor molecule, the product would allow perspiration, in the form of vapor, to pass through its membrane, thus making it a truly breathable material.

In 1971, the company began selling products under the trademarked name Gore-Tex. Though initially used in electronics, computers, and a variety of industrial applications, the company entered the outdoor retail market in 1976 when Early Winters began selling tents and rain jackets made with Gore-Tex. Later that same year, Marmot introduced the first down sleeping bag manufactured with Gore-Tex, while Synergy Works began selling parkas made with the new synthetic product. In 1980, Gore-Tex introduced a laminate for use in hiking boots. Today, there are dozens of outdoor brands that use Gore-Tex in a variety of products, including Patagonia, The North Face, Vasque, Merrell, Black Diamond, Outdoor Research and Arc’teryx.

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