The Leyton Frost behavior of acetone droplets on the water surface caused by cleaning laboratory equipment
Japanese researchers have noticed that acetone droplets do not mix with water because of their own Leighton Frost effect, which is more common in water droplets on solid hot surfaces. They studied the fluid dynamics of this interaction, as well as the self propulsion of the Leighton Frost effect (with its own name, the Marangoni effect), to gain a better understanding of potential mechanics.
Stoffel Janssens, a fluid physicist from the Mathematical Soft Matter Unit at the Okinawa Institute of Science and Technology (OIST) in Japan, noticed an unusual interaction between water and acetone droplets floating on the water surface during due diligence and cleaning of laboratory equipment, as these droplets were flowing towards the drainage pipe.
Jason said, "I have noticed that sometimes droplets briefly suspend on the surface of the liquid before binding with it." "Due to my interest in this phenomenon, I conducted a literature study from which I concluded that a thin layer of gas between the droplets and the surface of the liquid can prevent merging
In other words, Janssens noticed that acetone droplets were not mixed with water because of their own Leighton Frost effect, which is more common in water droplets on solid hot surfaces. Taking water as an example, water droplets float on the vapor layer formed when they meet a hot surface. Janssens and his colleagues at OIST and the National Institute of Materials Science in Japan studied the fluid dynamics of this interaction, as well as the self propulsion of the Leighton Frost effect (which has its own name, the Marangoni effect), to understand more potential mechanics. Their surprising results were published in this week's AIP Journal of Fluid Physics.
Usually, acetone (the main component of most nail washing water) and water are miscible, which means that unlike oil and water, they mix together and do not separate or form droplets when mixed.
The boiling point of acetone is 56 degrees Celsius, much lower than the boiling point of water, so when it approaches the surface of hot water, it will evaporate violently, "Jensen said. I assume that strong evaporation may form a gas layer between the acetone droplets and the water surface to suppress merging
Janssens and his co authors used high-speed camera technology to study the dynamics and potential mechanisms of room temperature droplets, closely monitoring variables such as droplet size and self droplet velocity. When they did this, they discovered some unexpected behaviors.
Jason said, "After analyzing the video obtained from high-speed camera imaging, I also noticed that a self-propelled droplet gradually submerged beneath the undisturbed water surface." "This immersion begins when the horizontal velocity of the droplet is about 14 centimeters per second. Finally, after carefully measuring the displacement of several droplets, we concluded that soaking causes resistance
They found that acetone droplets will move on the water surface until they reach a certain speed, pull them below the water surface, remain droplets, and then they will be subject to resistance from the surrounding water.
Janssens said, "To our knowledge, this immersion type of resistance is not described in the literature, and it is important to consider this when measuring the resistance of small objects supported by the liquid gas interface." In addition, aquatic creatures such as water striders, water spiders, and wandering beetles may use the immersion resistance to move.
Even more strangely, they found that the faster the droplets moved below the surface, the faster the speed.
Janssens said, "We observed that droplets accelerate faster with increasing horizontal velocity until they immerse themselves in water." "This initial runaway effect may attract interest in future research involving self propulsion driven by the Marangoni effect
By comparing their data with the theoretical model, Janssens and his colleagues developed a strategy to estimate the thickness of the vapor layer supported by droplets. However, there is still much to learn about this unusual system, and Janssens' team is still working hard to investigate this issue.
Janssens said, "Due to many unknown phenomena in this work, there is still a lot of work to be done." "I designed some control experiments to deepen our understanding of non coalescence.”
