A better way to shed water

MIT researchers find that lubricated, nanotextured surfaces improved performance of condensers in power and desalination plants. Condensers are a crucial part of today's power generation systems: About 80 percent of all the world's powerplants use them to turn steam back to water after it comes out of the turbines that turn generators. They are also a key element in desalination plants, a fast-growing contributor to the world's supply of fresh water. Now, a new surface architecture designed by researchers at MIT holds the promise of significantly boosting the performance of such condensers. The research is described in a paper just published online in the journal ACS Nano by MIT postdoc Sushant Anand; Kripa Varanasi, the Doherty Associate Professor of Ocean Utilization; and graduate student Adam Paxson, postdoc Rajeev Dhiman and research affiliate Dave Smith, all of Varanasi's research group at MIT. The key to the improved hydrophobic (water-shedding) surface is a combination of microscopic patterning - a surface covered with tiny bumps or posts just 10 micrometers (millionths of a meter) across, about the size of a red blood cell - and a coating of a lubricant, such as oil. The tiny spaces between the posts hold the oil in place through capillary action, the researchers found.