The dynamics of hydrogen peroxide over a very hot surface

What is it about?

When a liquid droplet is dropped over a surface whose temperature is much higher than the boiling point of the liquid, it levitates. This is called the Leidenfrost effect, and is caused by the liquid evaporating into a vapor cushion beneath the droplet, effectively isolating it from the surface. Liquid mixtures, such as water and hydrogen peroxide, may produce unexpected effects when used in such a context. This particular mixture was studied here, and the effects of surface temperature and hydrogen peroxide concentration were quantified for such Leidenfrost droplets.

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Photo by Thomas Kinto on Unsplash

Photo by Thomas Kinto on Unsplash

Why is it important?

Liquid droplets composed of two different fluids, called binary mixtures, may be subject to a change in composition as they evaporate. This occurs when the components have different boiling points, leading one of them to evaporate preferentially. In the case of a water and hydrogen peroxide mixture, water will evaporate first as it has a lower boiling point than the peroxide. Since the hydrogen peroxide is unstable, especially at higher temperatures, this makes the whole droplet unstable. As seen in the results, this leads to the droplet fracturing and ejecting secondary, very small, droplets. This behavior can affect systems such as decontamination enclosures using hydrogen peroxide gas.