(PhysOrg.com) -- Whether gazing into lava lamps or watching balsamic vinegar mix with olive oil, people have long been transfixed by the seemingly mystical way that droplets of one liquid find each other within another liquid and join together. Conventional scientific wisdom has held that this merging of liquid droplets, a process called coalescence, is enhanced by applying an electrical field, but a new study, which will be published in the Sept. 17 issue of the journal Nature, shows that an increased electrical field actually can prevent droplets from merging.


"These surprising results could lead to improved applications in diverse fields including petroleum purification, food-oil processing and even biodiesel production," said Andrew Belmonte, an associate professor of mathematics at Penn State and one of the leaders of the project. "The results also could increase our understanding of atmospheric high-voltages that are generated in thunderstorms."

According to William Ristenpart, an assistant professor at the University of California at Davis and another of the project's leaders, "It has long been assumed that oppositely charged droplets experience an attractive force that encourages them to coalesce. This study, however, demonstrates that while droplets move toward each other when a low-strength electrical field is applied, those same droplets actually are repelled from one another after they make contact under higher-strength electrical fields."