American chemists from the University of Chicago explained mathematically for the first time why water turns into ice at different temperatures. Their calculations will allow you to accurately control the process of snow and ice formation. The study was published on: To collect Proceedings of the annual meeting of the American Chemical Society (ACS).
It is generally accepted that water changes its state of aggregation from liquid to solid at 0 °C. However, in reality, the phase transition temperature of water at normal pressure depends on various impurities. For example, to freeze completely pure distilled water, it would need to be supercooled to -40 °C.
Scientists have presented a theoretical model showing how structural details can affect the freezing point of water. These particles can be soot particles, bacteria, and even some proteins.
The team collected more than a hundred known measurements of how the angles between microscopic protrusions on the surface of particles affect the freezing point. They then used models to look at factors that contribute to the nucleation of ice crystals, such as how strongly water binds to surfaces and the angles between structural elements.
Finally, chemists derived a mathematical expression showing that certain angles between surface features facilitate the aggregation and crystallization of water molecules at relatively higher temperatures.
The researchers say their model could help develop materials with surfaces that can form ice more efficiently with minimal energy input. This principle can be used in ice or snow generators or used to seed clouds with particles that will cause snowfall.
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