Pushing droplets around
Controlling the way liquids spread across a surface is important for a wide variety of technologies, including DNA microarrays for medical research, inkjet printers and digital lab-on-a-chip systems. But until now, the designers of such devices could only control how much the liquid would spread out over a surface, not which way it would go.New research from mechanical engineers at MIT has revealed a new approach that, by creating specific kinds of tiny structures on a material’s surface, can make a droplet spread only in a single direction.A report on the new work, by Esther and Harold E. Edgerton Assistant Professor of Mechanical Engineering Evelyn N. Wang and graduate students Kuang-Han Chu and Rong Xiao, was published on March 28 in the journal Nature Materials.The system Wang and her team developed is completely passive, based on producing a textured surface with tiny pillars shaped in specific ways to propel liquid...