A symmetrical droplet (top) forms on a surface with straight nano-pillars, while on a surface with bent pillars (bottom) the droplet extends out only to the right (Images: Kuang-Han Chu, Rong Xiao and Evelyn N. Wang)
By creating specific kinds of tiny structures on a material’s surface MIT researchers have made a liquid spread only in a single direction. While this may not appear to be a momentous breakthrough it has important implications for a wide variety of technologies, including micro-arrays for medical research, inkjet printers and digital lab-on-a-chip systems. Up 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. This new system changes that.