Many paints have water-repellent properties, such as waxing the car, which can make the water drops easier to slip. However, for airplanes, rainwater hits the fuselage and freezes in a very short period of time to bury a safety hazard, so better waterproof technology is needed.
The Massachusetts Institute of Technology (MIT) invented a new design based on a research result six years ago that could further improve the waterproofing effect.
Six years ago, the study proposed adding some subtle ridges to the surface material to help break the shape and symmetry of the water droplets, thus speeding up the waterball's velocity away from the surface by 40%. The shortening of the contact time between the water droplets and the surface of the material also means that the heat exchange time between the two becomes shorter, and the probability of the water droplets freezing on the surface is reduced.
But this is not enough. Researchers say that the contact time of water droplets with the surface is one of the factors, and the area of contact between the water droplets and the surface is another important factor.
Researchers say that the breakage of water droplets on the material greatly increases the contact area between the two. This not only speeds up the freezing of water droplets on the wing, but also increases the chance that salt accumulation will remain on the surface when it encounters splashing seawater. Salt is corrosive and can damage surface materials.
This recently published study in the journal《美国化学协会.纳米》(ACS Nano) invented a ring-shaped small groove structure that reduces the contact area between water droplets and the surface.
The researchers designed a slightly raised annular groove on the surface of the material. As the water droplets collide with the edge of the groove, they are also guided away from the surface of the material, and contact with the surface of the material is minimized.
According to the researchers, "the combination of the two methods reduces the time and area of contact between the water droplets and the surface of the material by 90%."