Researchers in Finland have been working on a unique new material that can be used for computing: water drops. A team at Aalto University has been working on using collisions of water droplets on superhydrophobic surfaces to serve as the basis for electricity-free computing. A superhydrophobic surface is one that is very highly water-repellent, causing water drops to skid about rather than be absorbed by and thus wet the surface. This is also referred to as the “Lotus effect,” as the leaves of the lotus plant are the emblematic superhydrophobes. The surface the researchers used was copper-based, with a modified silver coating. The surface became so water repellent that water drops rolled about when tilted at the slightest angle. The paths of the droplets could be controlled by etching tiny grooves into the surface. Via Inhabitat:

Using this method, the researchers demonstrated that water droplets could be used to demonstrate “superhydrophobic droplet logic”. In the university’s press release, the team used the example of a memory device that was built where water droplets act as bits of digital information. They also demonstrated devices for elementary Boolean logic operations.

Furthermore:

The team also discovered that once the water droplets were loaded with reactive chemical cargo, the onset of a chemical reaction could be controlled by droplet collisions. This combination of the collision-controlled chemical reactions with droplet logic operations potentially enabled programmable chemical reactions where single droplets were able to serve simultaneously as miniature reactors and bits for computing.

The research was published in the journal Advanced Materials. Earlier this summer, the same researchers, also working with superhydrophobic materials, created a prototype display that uses nothing but air and water.