What Makes Super Glue So Super?

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.

The Prehistoric Bacteria That Helped Create Our Cells Billions of Years Ago

We owe the existence of our cells—the very building blocks of life—to a chance relationship between bacteria that occurred more than 2 billion years ago. Flash back to Bio 101, and you might remember that humans, plants, and animals have complex eukaryotic cells, with nucleus-bound DNA, instead of single-celled prokaryotic cells. These contain specialized organelles such as the mitochondria—the cell’s powerhouse—and the chloroplast, which converts sunlight into sugar in plants.

Mitochondria and chloroplasts both look and behave a lot like bacteria, and they also share similar genes. This isn’t a coincidence: Scientists believe these specialized cell subunits are descendants of free-living prehistoric bacteria that somehow merged together to form one. Over time, they became part of our basic biological units—and you can learn how by watching PBS Eons’s latest video below.

Stones, Bones, and Wrecks
Buckingham Palace Was Built With Jurassic Fossils, Scientists Find

The UK's Buckingham Palace is a vestige from another era, and not just because it was built in the early 18th century. According to a new study, the limestone used to construct it is filled with the fossilized remains of microbes from the Jurassic period of 200 million years ago, as The Telegraph reports.

The palace is made of oolitic limestone, which consists of individual balls of carbonate sediment called ooids. The material is strong but lightweight, and is found worldwide. Jurassic oolite has been used to construct numerous famous buildings, from those in the British city of Bath to the Empire State Building and the Pentagon.

A new study from Australian National University published in Scientific Reports found that the spherical ooids in Buckingham Palace's walls are made up of layers and layers of mineralized microbes. Inspired by a mathematical model from the 1970s for predicting the growth of brain tumors, the researchers created a model that explains how ooids are created and predicts the factors that limit their ultimate size.

A hand holding a chunk of oolite limestone
Australian National University

They found that the mineralization of the microbes forms the central core of the ooid, and the layers of sediment that gather around that core feed those microbes until the nutrients can no longer reach the core from the outermost layer.

This contrasts with previous research on how ooids form, which hypothesized that they are the result of sediment gathered from rolling on the ocean floor. It also reshapes how we think about the buildings made out of oolitic limestone from this period. Next time you look up at the Empire State Building or Buckingham Palace, thank the ancient microbes.

[h/t The Telegraph]


More from mental floss studios