Remember the superhero fashion designer in The Incredibles? Nature unfolds the true story of a “super-material” that repels liquids so well, it resists molten metal:
Kripa Varanasi, a mechanical engineer at the Massachusetts Institute of Technology in Cambridge, and his colleagues used a water-repellent material which they further engineered by adding tiny ridges 0.1 millimetres high.
They then recorded water droplets hitting the surface with a high-speed camera that filmed at 10,000 frames per second or more. The ridges forced the liquid to splash asymmetrically, so that it recoiled faster than on a macroscopically smooth surface. The time that the water spent in contact with the surface fell by 37% compared to the same material with no ridges, the authors measured.
The researchers repeated the experiment with droplets of molten tin. On a surface without ridges, the liquid metal quickly solidified. But the effect of the ridges was strong enough to make the droplets bounce off while still liquid.
Video at the link.