What is it about?
This study looks at how drops of volatile liquids, like mixtures of acetone and isopropanol, behave when they hit a surface at normal room temperature and pressure. Unlike typical conditions where a hot surface creates a vapor layer that affects the drop, this research shows that even at normal temperatures, the evaporation of these liquids can create enough force to change how the drops interact with the surface. By adjusting the amount of acetone in the mix, the researchers kept the surface tension the same but changed the vapor pressure. They used high-speed cameras to see how quickly the drops started to wet the surface. They found that drops with higher vapor pressure (like pure acetone) wet the surface more easily, but certain mixtures (around 50-66% isopropanol) caused drops to bounce off the surface more strongly. This shows how the evaporation of volatile liquids can lead to interesting and different behaviors when the drops hit a surface.
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Photo by Shlomo Shalev on Unsplash
Why is it important?
Understanding the behavior of volatile liquid drops on surfaces at normal temperatures is crucial for improving industrial processes, such as those in pharmaceuticals, electronics, and printing, where precise fluid control is essential. It can enhance the efficiency of cooling systems that rely on evaporative cooling, inform the development of advanced surface treatments like waterproofing and self-cleaning coatings, and aid in environmental management of spills.
Perspectives
We explore the wetting dynamics of volatile drops by visualizing the interfacial air layer using the total internal reflection microscopy (TIRM) technique.
Dr Ziwen He
University of Minnesota Twin Cities
Read the Original
This page is a summary of: Dual nature of volatility on drop wetting dynamics of acetone–isopropanol mixtures on ultrathin smooth oil films, Physics of Fluids, January 2023, American Institute of Physics,
DOI: 10.1063/5.0131299.
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