Last year, researchers from MIT discovered that when water droplets spontaneously move away from superhydrophobic surfaces during condensation, the droplets can gain electric charge in the process. Now the researchers have demonstrated that this process can generate small amounts of electricity, and as an additional benefit, the system could also produce clean water. The device itself consists of a series of interleaved flat metal plates. The system is based on the fact that droplets on a superhydrophobic surface convert surface energy to kinetic energy as they merge to form larger droplets. This sometimes causes the droplets to spontaneously move, enhancing heat transfer by 30 percent relative to other techniques. The researchers later found that in that process, the droplets gain a small electric charge.By giving the second plate a hydrophilic surface, power can be generated. As the droplets move, they carry charge from one plate to the other. If the two plates are connected through an external circuit, that charge difference can be harnessed to provide power. In a practical device, two arrays of metal plates would be interleaved, so that they are close but not in contact. The system would operate passively, with no moving parts.
Source: MIT
