Special surface manipulation forces dropped liquids to spiral when they rebound

March 7, 2019 by Bob Yirka, Phys.org report

A team of researchers affiliated with several institutions in China has found a way to force liquid drops to spiral as they rebound after landing on a manipulated surface. In their paper published in the journal Nature Communications, the group describes how their method works and possible applications.

Most people are well aware of what happens when a drop of water or other liquid falls onto a flat —it rebounds in random ways, quite often making a mess. In this new effort, the researchers changed the plain to one they describe as heterogeneous, which forced the drop to upward as it rebounded in very specific ways.

To change the way a drop would rebound, the researchers first noted that one ineffective approach would be to wet the surface—that would only result in "plopping." Instead, they started by coating an aluminum plate with a nonstick chemical very much like that found in cooking sprays. They followed that up by placing a mask on some parts of the surface while leaving others exposed—those left uncovered were bathed in , which made them "wettable"—water dropped on it would spread more than normally before rebounding. Notably, the masks were made in whirl patterns reminiscent of pinwheels.

When a drop of landed on the treated surface, those parts of it that struck the wettable spirals tended to stick a little before rebounding. Those that struck the parts that had been masked, on the other hand, rebounded nearly instantly, because they had been made hydrophobic. This led to "non-axisymmetric spinning forces" applied to different parts of the drop at the same time. The result was twisting of the liquid, forcing the drop to spin as it rebounded upward.

The researchers created multiple swirl patterns and found that one of them forced the drop to spin at approximately 7,300 revolutions per minute. They suggest their technique might be used in hydro-energy collection efforts, self-cleaning devices or perhaps as a way to de-ice plane wings or car windshields.

Explore further: Drops of water found to spring from oscillating surface faster than the surface moves

More information: Huizeng Li et al. Spontaneous droplets gyrating via asymmetric self-splitting on heterogeneous surfaces, Nature Communications (2019). DOI: 10.1038/s41467-019-08919-2

Related Stories

Leidenfrost effect drops found to be self-propelled

September 12, 2018

A team of researchers at Physique et Mécanique des Milieux Hétérogènes in France has found that Leidenfrost effect drops move around on a hot pan because they are self-propelled. In their paper published in the journal ...

A way to create liquid droplets inside of air bubbles

February 8, 2018

A team of researchers at Zhejiang University in China has developed a technique to create liquid droplets inside of air bubbles. In their paper published in the journal Physical Review Letters, the group describes the technique ...

Recommended for you

Coffee-based colloids for direct solar absorption

March 22, 2019

Solar energy is one of the most promising resources to help reduce fossil fuel consumption and mitigate greenhouse gas emissions to power a sustainable future. Devices presently in use to convert solar energy into thermal ...

Physicists reveal why matter dominates universe

March 21, 2019

Physicists in the College of Arts and Sciences at Syracuse University have confirmed that matter and antimatter decay differently for elementary particles containing charmed quarks.

ATLAS experiment observes light scattering off light

March 20, 2019

Light-by-light scattering is a very rare phenomenon in which two photons interact, producing another pair of photons. This process was among the earliest predictions of quantum electrodynamics (QED), the quantum theory of ...

How heavy elements come about in the universe

March 19, 2019

Heavy elements are produced during stellar explosion or on the surfaces of neutron stars through the capture of hydrogen nuclei (protons). This occurs at extremely high temperatures, but at relatively low energies. An international ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.