Water Bugs Inspire Oil-Repellent CoatingWater Bugs Inspire Oil-Repellent Coating

Biomimicry is often used as inspiration for new materials and new methods of constructing materials. Now Chinese researchers have created a substance that can repel oil underwater by taking inspiration from water strider insects.

Most oil-repelling substances don't work underwater, or even if they just get wet. Developing such materials would be a boon to helping aquatic robots move through water to handle oil and clean up oil spills. It could also be used as a coating to prevent a car's windshield from getting gummed up with dirt and bugs, or as a coating on ship hulls to prevent the growth of barnacles and other sea creatures.

Water-strider insects, which look like big mosquitos, can skate between the surfaces of air and water without sinking because of the chemistry and physics of microprojections on their legs that are lined with nanogrooves. Led by Shutao Wang, of the Chinese Academy of Sciences, researchers have constructed a device that can float between the surfaces of oil and water in a parallel way, without either sinking or getting oily. The 5-cm-long "oil strider" device works like the bug because of the combination of its construction with a super-oleophobic coating on the device's four metal legs that repels oil even underwater.