The manufacturers trick is to vacuum pack the superglue, keeping the adhesive substance away from contact with the air. That’s because it’s the moisture in the atmosphere that makes superglue sticky. Let’s explain how this happens using the example of the most famous superglue, Super Bonder. It is composed of molecules of ethyl cyanoacrylate, a sticky substance that naturally adheres to plastics or metals. Inside the packaging, the cyanoacrylate molecules are well separated from each other. Therefore, they do not stick to the tube. But when we open the package, everything changes: the humidity acts as a “hook” that connects the cyanoacrylate molecules, transforming the glue into the super sticky substance that we know. This reaction has a name: polymerization. “This is clearer in epoxy-type superglues, such as Araldite. In this case, the sticky substance comes in one package and the one that promotes polymerization in another. Before using the glue, we mix the two substances”, says chemist Henrique Toma, from USP. If you miss the mark and stick your fingers, don’t despair: once the glue has hardened, use a nail file to scrape it off. Hot water also helps soften the adhesive.
1. The adhesive substance of superglues is ethyl cyanoacrylate. In the package, the cyanoacrylate molecules do not have contact with the air and are far from each other. Therefore, they do not stick to the tube.
2. When the tube is opened, cyanoacrylate molecules encounter water molecules in the air. Steam acts as a bonding agent between cyanoacrylate molecules, holding them together and making them adhere to almost any material.