Water clings to most materials, either soaking in or beading up, depending on surface area and composition. The new material, etched from silicon, resembles a microscopic bed of grass. Each "blade" is a few nanometers thick--about 100,000 times smaller in diameter than a single human hair. When liquid drops onto the tiny blades, it suspends itself on their tips without sinking between. The blades "reduce the surface area the droplet feels," says Krupenkin, so the liquid beads up effortlessly. When the researchers charge the silicon with electricity, the energy field pulls the liquid down into the gaps, and the "nanograss" wets instantly.