Static electricity: a millennia-old phenomenon finally elucidated?

Who hasn't laughed while rubbing a balloon on their sweater and then bringing it close to their neighbor's hair to see it “fly up”? After more than 2,000 years of mystery, science may have finally uncovered the secrets of static electricity. Friction seems to be at the heart of the phenomenon, but how exactly does it work?

The first to take an interest in this phenomenon were the ancient Greeks, observing amber attracting objects after being rubbed. However, until recently, there was no solid theory explaining this familiar electricity in a precise manner.


Significant advances were made in the 18th century with Benjamin Franklin. He introduced the notions of positive and negative charges, but his theories on electrical fluids turned out to be imperfect. It is thanks to the work of Professor Laurence Marks' team, from Northwestern University, that the key to the mystery was found. They modeled static electricity at the nanometric level, highlighting the importance of friction.

Researchers discovered that when an object is rubbed, deformations occur at the front and back of it. These deformations cause the displacement of electrical charges, thereby creating a current. This explains how static electricity arises. The model developed by Laurence Marks is based on the concept of "elastic shear," meaning a material's ability to resist friction.

You can observe this resistance in your daily life: try sliding a glass on your table, or try to slide in socks on a smooth floor—you'll notice that you can initially glide, but that will quickly stop because the material (the table or the floor) applies resistance. It is precisely this resistance to sliding that forces the electrical charges to redistribute, consequently generating the electrical current observed during friction.

In Nano Letters, the researchers detail how these asymmetric charges are balanced by other free charges, leading to the formation of an electric current. The impact of this discovery goes far beyond our daily experiences with static electricity. For instance, explosions can occur in industries due to this poorly understood phenomenon until now.

Better control of this phenomenon could pave the way for a multitude of practical applications. For example, in the food industry, static electricity is already used to enhance coffee bean grinding, but it could also optimize the production of pharmaceutical powders. In the space sector, it could facilitate the assembly of particles for material manufacturing, or even be harnessed to collect cosmic dust during space exploration.

Why is static electricity so common in our daily lives?

Static electricity often manifests in everyday situations, like when you walk on a carpet or put on a wool sweater. This is due to how easily some materials like plastics or fabrics accumulate charges.

In daily life, this phenomenon might cause minor electric shocks, but it also finds industrial applications, like particle control or electrostatic printing.