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What Makes Super Glue So Super?

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Harry W. Coover receives from the National Medal of Science in the East Room of the White House, November 17, 2010. © Olivier Douliery/Pool/Corbis

Super Glue inventor Dr. Harry Coover died Saturday at his home in Kingsport, Tennessee. He was 94. Matt Soniak looks back at Coover's famous adhesive.

A Sticky Situation

In 1942, American scientists at Kodak Laboratories were looking for materials to make extra-clear plastic gun sights for infantry rifles. Harry Coover and Fred Joyner stumbled upon a few acrylate monomers (esters of acrylic acid that can bind to each other to form chains of molecules) that showed promise, but the monomers stuck to everything they touched. They wouldn’t do any good, so Coover shelved the formulas.

Nine years later, Coover was working at the research labs of the Tennessee Eastman Co., trying to find a tough, heat-resistant material for making jet canopies. He pulled out his old formulas from the war years and gave them another spin. They were, of course, sticky as ever. One researcher spread one of them between the prisms of a machine to see how refractive it was. He got the measurement he needed, but then couldn’t pull the prisms apart. He had to go to Coover with his tail between his legs and report that he had ruined a very expensive instrument. But Coover was delighted—he realized he had a unique adhesive on his hands.

The lab accident became a marketable product in 1958, when Kodak began selling the first cyanoacrylate glue, Eastman #910. Coover himself got to show off the first “super glue” the next year when he went on the TV show I've Got a Secret and used the glue to lift the show’s host completely off of the ground.

Glue’s Superpowers

Through the years, there have been plenty of cyanoacrylate adhesives, like #910, Loctite Quick Set, Super Bonder, Super Glue and Krazy Glue.

All of these glues get their power from cyanoacrylate polymers. A polymer is what happens when a bunch of monomers get together and attach to each other in repeating units. They form a chain or other structure that resists breaking and grabs any microscopic roughness it can find on other objects it touches. The only trigger cyanoacrylate polymers need to form is water—specifically, the hydroxide ions in it. Since there are minute traces of water on almost any surface, it’s easy for the glue to start a polymeric reaction anywhere. Once this reaction starts, it’s pretty difficult to stop, and the resulting molecular bonds don’t come undone easily.


Super glue can do more than stick things together, and it’s become a valuable tool in law enforcement. When you get cyanoacrylate warmed up, it releases fumes. When these fumes touch the moisture residue from fingerprints, white polymers are formed and fingerprints that might have otherwise been hard to see become plainly visible for analysis.


Speaking of warming cyanoacrylate up, super glue spontaneously combusts when enough of it makes contact with cotton or wool. See it in action here.

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Trying to Save Money? Avoid Shopping on a Smartphone
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Today, Americans do most of their shopping online—but as anyone who’s indulged in late-night retail therapy likely knows, this convenience often can come with an added cost. Trying to curb expenses, but don't want to swear off the convenience of ordering groceries in your PJs? New research shows that shopping on a desktop computer instead of a mobile phone may help you avoid making foolish purchases, according to Co. Design. Ying Zhu, a marketing professor at the University of British Columbia-Okanagan, recently led a study to measure how touchscreen technology affects consumer behavior. Published in the Journal of Retailing and Consumer Services, her research found that people are more likely to make more frivolous, impulsive purchases if they’re shopping on their phones than if they’re facing a computer monitor. Zhu, along with study co-author Jeffrey Meyer of Bowling Green State University, ran a series of lab experiments on student participants to observe how different electronic devices affected shoppers’ thinking styles and intentions. Their aim was to see if subjects' purchasing goals changed when it came to buying frivolous things, like chocolate or massages, or more practical things, like food or office supplies. In one experiment, participants were randomly assigned to use a desktop or a touchscreen. Then, they were presented with an offer to purchase either a frivolous item (a $50 restaurant certificate for $30) or a useful one (a $50 grocery certificate for $30). These subjects used a three-point scale to gauge how likely they were to purchase the offer, and they also evaluated how practical or frivolous each item was. (Participants rated the restaurant certificate to be more indulgent than the grocery certificate.) Sure enough, the researchers found that participants had "significantly higher" purchase intentions for hedonic (i.e. pleasurable) products when buying on touchscreens than on desktops, according to the study. On the flip side, participants had significantly higher purchase intentions for utilitarian (i.e. practical) products while using desktops instead of touchscreens. "The playful and fun nature of the touchscreen enhances consumers' favor of hedonic products; while the logical and functional nature of a desktop endorses the consumers' preference for utilitarian products," Zhu explains in a press release. The study also found that participants using touchscreen technology scored significantly higher on "experiential thinking" than subjects using desktop computers, whereas those with desktop computers demonstrated higher scores for rational thinking. “When you’re in an experiential thinking mode, [you crave] excitement, a different experience,” Zhu explained to Co. Design. “When you’re on the desktop, with all the work emails, that interface puts you into a rational thinking style. While you’re in a rational thinking style, when you assess a product, you’ll look for something with functionality and specific uses.” Zhu’s advice for consumers looking to conserve cash? Stow away the smartphone when you’re itching to splurge on a guilty pleasure. [h/t Fast Company]
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Animals
Elusive Butterfly Sighted in Scotland for the First Time in 133 Years

Conditions weren’t looking too promising for the white-letter hairstreak, an elusive butterfly that’s native to the UK. Threatened by habitat loss, the butterfly's numbers have dwindled by 96 percent since the 1970s, and the insect hasn’t even been spotted in Scotland since 1884. So you can imagine the surprise lepidopterists felt when a white-letter hairstreak was seen feeding in a field in Berwickshire, Scotland earlier in August, according to The Guardian.

A man named Iain Cowe noticed the butterfly and managed to capture it on camera. “It is not every day that something as special as this is found when out and about on a regular butterfly foray,” Cowe said in a statement provided by the UK's Butterfly Conservation. “It was a very ragged and worn individual found feeding on ragwort in the grassy edge of an arable field.”

The white-letter hairstreak is a small brown butterfly with a white “W”-shaped streak on the underside of its wings and a small orange spot on its hindwings. It’s not easily sighted, as it tends to spend most of its life feeding and breeding in treetops.

The butterfly’s preferred habitat is the elm tree, but an outbreak of Dutch elm disease—first noted the 1970s—forced the white-letter hairstreak to find new homes and food sources as millions of Britain's elm trees died. The threatened species has slowly spread north, and experts are now hopeful that Scotland could be a good home for the insect. (Dutch elm disease does exist in Scotland, but the nation also has a good amount of disease-resistant Wych elms.)

If a breeding colony is confirmed, the white-letter hairstreak will bump Scotland’s number of butterfly species that live and breed in the country up to 34. “We don’t have many butterfly species in Scotland so one more is very nice to have,” Paul Kirkland, director of Butterfly Conservation Scotland, said in a statement.

Prior to 1884, the only confirmed sighting of a white-letter hairstreak in Scotland was in 1859. However, the insect’s newfound presence in Scotland comes at a cost: The UK’s butterflies are moving north due to climate change, and the white-letter hairstreak’s arrival is “almost certainly due to the warming climate,” Kirkland said.

[h/t The Guardian]

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