Researchers find why friction causes static electricity

A group of researchers believes that it has relatively precisely identified the ways in which friction leads to static electricity. This is a phenomenon that probably everyone knows and that leads us to have to deal, almost daily, with small sparks or electrical discharges, in the great majority of innocuous cases, which can be caused by frictions of various kinds or various objects. A known example is that of hair that can stand up on the head.

A team of researchers at Northwestern University has created a new model that explains why rubbing two objects can produce static electricity or a triboelectric effect. In the study, published in Physical Review Letters, it is explained that it is the small protrusions, almost identifiable only at the atomic level, on the surface of the materials that bend when they come into contact to produce this electricity.

If you look at the nanoscale, in fact, every material, even the smoothest, is characterized by rough surfaces with countless protrusions. When two objects or materials come into contact and begin to bend with one another, these protrusions begin to deform. And it is these deformations that proved the tensions which in the end cause a small electric discharge, an effect called the flexoelectric effect.

“Our discovery suggests that triboelectricity, flexo-electricity and friction are inextricably linked,” says Laurence Marks, professor of materials engineering sciences at Northwestern as well as lead author of the study. “This provides a lot of information on customizing triboelectric performance for current applications and expanding functionality to new technologies.”