Everyone knows that metals are a rather heavy class of substances that have a high density and (if we are not talking about special alloys or ultra-thin sheets like foil) often sinks in water. However, researchers at the University of Rochester have been able to create a metal that simply refuses to sink. Even if it is deliberately immersed under the water surface, it will float to the surface.
How to create metal that won't sink in water
Responsible for the development is Professor of the Department of Optics and Physics at the University of Rochester Chunlei Guo and his team. To create the new material, the researchers used an innovative method that uses femtosecond laser flashes to "etch" the surface of metals. That is, very fast and intense laser flashes create micro- and nanoscale patterns on the metal surface, changing the structure of the substance. This allows the surface layer of the metal to trap and retain air, making the metal surface "superhydrophobic" or, more simply, water-repellent.
However, during testing, the researchers found that after prolonged immersion in water, surfaces can begin to lose their hydrophobic properties. And then the attention of scientists was attracted by … spiders and ants.
For example, the Argyroneta waterfowl spiders create an underwater domed web - the so-called diving bell, which they fill with air, which they carry from the surface on their legs and abdomen. In the same way, some species of ants are able to form a "water bubble" by holding air bubbles on the surface of the body.
As a result, a team of scientists developed a structure in which two metal plates were covered with tiny "patterns" just like before. Only now they put these plates on top of each other, turning them in with a "pattern". There was enough space between the plates to capture and hold air, which prevented the metal structure from sinking.
Moreover, the superhydrophobic structure remains afloat even after significant structural damage. As part of the experiment, scientists made 6 holes in the plates with a diameter of 3 millimeters and one hole with a diameter of 6 millimeters. At the same time, the plates continued to float on the surface of the water.
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The metal continues to float even after extensive damage.
The team claims a similar process can be used to modify any kind of metal. When the experts first tested the new technology, it took them one hour to modify the 2.5 by 2.5 centimeters metal area. Now, using lasers seven times more powerful, the process has significantly accelerated and in general, according to the developers, "the technology is ready for commercial use."
Vladimir Kuznetsov