| Sep 07, 2012 |
Towards computing with water droplets - superhydrophobic droplet logic (w/videos) |
| (Nanowerk News) Researchers ar 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 ("Rebounding Droplet-Droplet Collisions on Superhydrophobic Surfaces: from the Phenomenon to Droplet Logic"), 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. |
| Using the tracks, the researchers demonstrated that water droplets could be turned into technology, “superhydrophobic droplet logic”. For example, a memory device was built where water droplets act as bits of digital information. Furthermore, devices for elementary Boolean logic operations were demonstrated. These simple devices are building blocks for computing: |
| Furthermore, 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 where single droplets serve simultaneously as miniature reactors and bits for computing: |
| "It is fascinating to observe a new physical phenomenon for such everyday objects – water droplets," says Robin Ras, an Academy Research Fellow in the Molecular Materials research group. |
| "I was surprised that such rebounding collisions between two droplets were never reported before, as it indeed is an easily accessible phenomenon: I conducted some of the early experiments on water-repellent plant leaves from my mother’s garden," explains a member of the research group, Henrikki Mertaniemi, who discovered the rebounding droplet collisions two years ago during a summer student project in the research group of Ras and Academy Professor Olli Ikkala. |
| The researchers foresee that the present results enable technology based on superhydrophobic droplet logic. Possible applications include autonomous simple logic devices not requiring electricity, and programmable biochemical analysis devices. |
| Source: Aalto University |
