You might remember them from your high school’s chemistry and physics lectures. Van der Waals interactions are one of the weakest interactions known to our world. Nevertheless, they are very important and you can find them literally everywhere around you.

They influence the way molecules behave, how they interact with each other and create highly ordered complicated structures. Therefore, they can also affect the functionality of such complicated structures.

Scientists from the Swiss Nanoscience Institute and the University of Basel managed to measure these interactions between individual atoms — something that has never been done before.

Their results were published in the highly prestigious journal Nature Communications.

Everywhere around us

Van der Waals interactions are weaker than any other type of chemical bond. Inspite of being so weak they influence the three dimensional structure of proteins or even the overall shape of polymer structures. They can be found between water molecules, or individual sheets of graphite, which are really soft thanks to very low strength of these interactions.

Van der Waals interactions are literally everywhere around us. Source — Martina Ribar Hestericová

All these examples might be quite hard to imagine. However, Van der Waals forces can be seen on a bigger scale too. One of the most common examples is the gecko — a lizard which is able to climb on very smooth surfaces.

The gecko owes its Spiderman-like abilities to nothing else than van der Waals interactions. Combined strength of these interactions between the surface and microscopic hair on its legs allow the gecko to climb even on glass. The amount of hair is quite astonishing too; each square centimeter of a gecko’s foot contains about 150'000 of them.

Noble gases

In order to measure the van der Waals forces between individual atoms, Basel scientists had to choose an adequate material for measurements. They decided to measure atoms of inert gases.

According to Shikegi Kawai, former postdoc at the University of Basel and leading author of the study, “the inert gases have a closed shell. If we would have used a different type of atom, another interactions could be formed, like covalent bonds. Then we could not directly measure van der Waals interactions only. This is the reason why we chose them.”