And Then There Was Teflon

A Brief History of Technology, Part 2  –  Through the Teflon Looking Glass

The Marvelous Roy Plunkett

Lets step away from heavy-handed theory and digital technology for a minute and look at Teflon.  As discussed in last weeks post, technology is an intricate network of systems, and it is material.  But material is also technology.  The development of materials and their applications follow the same path as any other technology; through the innovation of technological information already obtained.  The evolution of Teflon (or PTFE as it is generically known) and expanded PTFE (ePTFE) looks something like this:

An accident

An atomic bomb

A frustrated wife

A desire for profit

A whole lot of sports and transportation

My mother always told me not to play with chemicals; “they’re dangerous,” she’d say with cautionary gravity.  I wonder what Roy Plunkett’s mother told him as a kid.  I’ll bet you it wasn’t anything like “don’t play with chlorofluorocarbon chemical compounds Roy, you might not like what you discover.”  I’ll also bet you that, contrary to his mother’s hypothetical warnings; he most certainly liked the white powder he stumbled across accidentally while trying to create a new type of Freon in 1938.

No it’s not cocaine
Found at 3M

Though not registered, named and trademarked by DuPont as “Teflon” until 1945, it wasn’t long after Plunkett’s “discovery” of polytetrafluoroethylene (or PTFE if you don’t have “CTRL C” like me) in 1938 that the advantages of the accidental technology were realized.  Due to its low friction nonstick capacity, mechanical applications associated with bearings and gears were almost immediately assumed.  The Manhattan Project, another early adopter, embraced the use of the fluorinated polymer in the early 1940’s to coat the seals and valves of pipes containing uranium.  It worked; we made an atomic bomb, and we won the Second World War.  Easy, right?

Then, in 1954, there was the wife of French engineer Marc Grégoire, who, after nearly exhausting her best efforts to persuade her husband to spend less time fishing and more time helping her in the kitchen – finally succeeded in convincing her stubborn husband to try his nonstick fishing tackle resin on her frying pan.  We were now, finally, cooking with Teflon.  This of course led to what is now an age-old question: if Teflon is nonstick, how the hell do they get it to stick to the pan?  Well you don’t really; you just get it on there as good as you can.  Basically, you scratch the hell out of a pan to create some sort of abrasive surface, spray on a layer of Teflon primer that tries desperately, albeit slowly, to escape the clutches of the abrasion while you get it really really hot, solidifying the Teflon primer.  Then, another coating of Teflon and yet another high heat bake.  This of course, is extremely energy intensive, especially considering the amount of eggs we the human race like to eat in a year.

Trade secrets in business can be a wonderful advantage to securing market share in a sector.  They can also destroy you.  When New Zealander John Cropper built a machine to produce expanded PTFE tape in 1966, he made the decision to keep his process close to the vest and have his employees sign confidentiality agreements rather than filing for a patent.  This might have been a good decision, if it weren’t for Bob Gore and the reckonable force known as the United States Patent and Trademark Office.  Independently making the same discovery three years later, Gore began producing breathable, microporous water repellent fabrics for use in his double-layered protective wear.  However, Gore made a different decision in 1969, releasing his findings to the public under the trademark Gore-Tex and filing two different U.S. patents in 1976 and 1980.

#gortex
Found on Instagram – campbellcarly

Architectural applications using PTFE as a material have been around for a while.  Typically, such material applications are used as roofs, or roofing membranes.  The largest and most notable instance would be the roof of the Hubert H. Humphrey Metrodome in Minneapolis, Minnesota.  Encompassing roughly 20 acres, the fabric dome is composed, similar to it’s ePTFE muse Gore-Tex, of two layers: an inner layer of proprietary acoustical fabric, an outer layer made of fiberglass with a PTFE coating manufactured and installed by Birdair, Inc. and an air space in-between which acts as insulation as well as a void for warm air to be blown through to melt any accumulated snow.  It’s entirely self-supporting – with a little assistance from air pressure that is.  But of course, we all know what happens when you get a little too much snow on 20 acres of fabric supported by air.

The Metrodome is not the only claim-to-fame of Birdair Structures.  It’s not even their only dome.  Toting the term tensile architecture, Birdair specializes in lightweight architectural fabric membranes, most of which are found in sporting arenas, airports and various other transportation stations.  Notable for its sustainable features, such as a material efficiency, an ability to use metals with a high amount of recycled content and an ability for efficient daylighting strategies.  Of course, these are the marketing claims of Birdair, the validity of which I will investigate later.  Still, their systems do use less material.  And inherent of that material, they are light enough to allow for more efficient daylighting strategies as well as, what I will only assume for now, greater energy efficiency if desired to mechanically control such a system.

Birdair Tensile Roof
Jawaharlal Nehru Stadium
Delhi, India

R. H. Holley

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