Researchers in Aalto University have developed a new concept for computing, using water droplets as bits of digital information. This was enabled by the discovery that upon collision with each other on a highly water-repellent surface, two water droplets rebound like billiard balls.
In the work, published in the journal Advanced Materials, the researchers experimentally determined the conditions for rebounding of water droplets moving on superhydrophobic surfaces. In the study, a copper surface coated with silver and chemically modified with a fluorinated compound was used. This method enables the surface to be so water-repellent that water droplets roll off when the surface is tilted slightly. Superhydrophobic tracks, developed during a previous study, were employed for guiding droplets along designed paths.