KAIST develops method to prevent liquid dripping

More than 500 years ago, the Renaissance master Michelangelo endured paint dripping onto his face for more than four years while painting "The Creation of Adam" on the ceiling of the Sistine Chapel. The experience was so grueling that he famously described the task as closer to torture than painting. Now, researchers in South Korea say they have developed a technique that can keep liquid from falling under the pull of gravity.

The Korea Advanced Institute of Science and Technology said Thursday that a team led by mechanical engineering professor Kim Hyeong-su has proposed a method to control gravitational instability by mixing a small amount of volatile liquid into another liquid. When liquid collects on an upper surface and begins to collapse downward under gravity, such as paint dripping from a ceiling during painting, the phenomenon is known as Rayleigh–Taylor instability.

The researchers focused on how a suspended liquid behaves when a small amount of volatile substance is added. As the volatile component evaporates, the liquid’s surface tension begins to vary across different areas. Surface tension is the force that pulls a liquid’s surface inward and allows droplets to maintain a rounded shape. When surface tension differs across regions, areas with stronger tension pull toward those with weaker tension. The team found that this effect can help hold the liquid in place and prevent it from falling.

As the volatile liquid evaporates, it generates a force that pulls the liquid upward, counteracting gravity and stabilizing the fluid.

Applying this principle could make it possible to produce thinner and more uniform liquid films in processes such as precision coating and layered manufacturing. The researchers said the concept could also be extended to technologies designed to control fluids in specialized environments, including space.


최지원 jwchoi@donga.com