Researchers from Aalto University in Finland believe water droplets could be used as bits of digital information in a new computing approach. The team has based its discovery upon the fact that, when two water droplets collide on a highly water repellent surface, they rebound like billiard balls.
In the study, a copper surface was coated with silver and chemically modified with a fluorinated compound. This allowed the surface to be so water repellent that water droplets rolled off when the surface was tilted slightly. Superhydrophobic tracks, developed during a previous study, were used to guide droplets along designed paths.
Using the tracks, the researchers demonstrated that water droplets could be used to create ‘superhydrophobic droplet logic’. A memory device has been built in which water droplets act as bits of digital information, as have devices for performing elementary Boolean logic operations.
Meanwhile, when the water droplets are loaded with reactive chemical cargo, the onset of a chemical reaction could be controlled by droplet collisions. Combination of the collision controlled chemical reactions with droplet logic operations potentially enables programmable chemical reactions, in which single droplets serve simultaneously as miniature reactors and bits for computing.
The researchers believe the approach may have application in autonomous simple logic devices that do not require electricity and in programmable biochemical analysis devices.