Scientists have developed a surface that remains dry even under water

Researchers from the Harvard John A. School of Engineering and Applied Sciences. Paulson (SEAS) developed a surface material that remains dry for months underwater and is also excellent at resisting the adhesion of bacteria and marine organisms such as barnacles.

When developing such a material, scientists were inspired by the abilities of the water spider (Argyroneta aquatica), also known as the bell spider. This is the only known species of spider that lives almost entirely underwater. Millions of coarse water-repellent hairs on its body trap air around its body, creating an oxygen reservoir and a barrier between the spider's lungs and water. The thin layer of air trapped by the hairs is called the plastron. This is exactly what the researchers tried to recreate.

In practice, developing a rough surface like that of a spider has proven to be quite a challenge. Scientists have been working on it for decades. The thing is that plastron reproduction makes the surface mechanically weaker and more susceptible to small changes in temperature and pressure.

So far, it has been possible to create a similar aerophilic surface from a titanium alloy that attracts and releases bubbles of air or gas, with nano-sized roughness obtained using electrochemical oxidation.

To test the surface's stability, the researchers bent it, twisted it, doused it with hot and cold water, and sanded it with sand and steel—it remained aerophilic. After the rafting survived more than 208 days of continuous immersion in water (at the time of publication research the plastron was still submerged and showed no signs of destruction) and hundreds of dives into the Petri dish. The surface was able to significantly reduce the growth of bacteria and barnacles, and completely prevent mussels from sticking.

Researchers say the surface has many uses. It could be used in biomedical devices to reduce post-surgical infection or to prevent corrosion of underwater pipelines and sensors. Stability, ease of manufacture and scalability make it incredibly valuable for real-world applications, added scientists.