You see in this drop as if liquid marble – and it turned out from salted water. It is so salty that crystals fall out as soon as it begins to evaporate. Falling out of crystals is an interesting process and at the same time an interesting object of research.
Mineral salts are a real disaster for power plants. Electricity is generated from heat, and huge masses of water circulate in the cooling systems of generators. The average power plant drives through itself 4.5 billion liters per year!
But even the purest water contains mineral salts, albeit in scanty amounts. Salts are deposited in pipes and are very annoying for power engineers. Developed economies lose $ 100 billion annually from reduced throughput and heat transfer in power plant cooling systems.
To cope with this problem, you need to pay attention not to the composition of the water, but to the surface that it cools.
In a recent study, scientists at the Massachusetts Institute of Technology found that the shape of crystals depends on the structure of the surface at the micro and nanoscale. If the surface is dotted with micro-wells, water evenly spreads over it. Then the crystals cover the surface with an even layer. But if the surface is covered with nanocracks, crystals grow upward, and salt deposits take the form of an elephant or jellyfish. These small creatures are much easier to remove from the surface, and sometimes they just wash off themselves.
Massachusetts researchers made zoomorphic crystals dance and roll, changing the temperature in the experimental tube. It turned out funny, but they did not do it for fun. Playing all these performances with the participation of surfaces of different structures, temperatures and heating rates, dancing crystals, they had as their goal to create a fundamentally new cooling system for generators, in which not even fresh, but sea water could circulate, and its reserves are endless.
По материалам статьи «Crystal Critters: Self-ejection of Crystals from Heated, Superhydrophobic Surfaces»; Samantha A. McBride, Henri-Louis Girard, Kripa K. Varanasi; журнал Science Advances, апрель 2021 г.
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