July 31, 2017 Essentially, when the nanopillars are tall and slender, the droplets formed inside and on the crevices can jump off the surface at a much smaller size, down to two micrometers. Likewise, short and stout pillars increase the size of the droplet required to jump -- up to 20 micrometers in the case of Mulroe's experiment. Credit: Virginia Tech

By better understanding the behavior of water in its smallest form, a Virginia Tech professor and his undergraduate student could be improving the efficiency of removing condensation in a major way.

Jonathan Boreyko, an assistant professor in the Department of Biomedical Engineering and Mechanics in the Virginia Tech College of Engineering, has been studying "jumping" dew droplets since he discovered the phenomenon in graduate school.

According to Boreyko, dew droplets only jump from water-repellent surfaces when they reach a large enough sizeabout 10 micrometersbut it was unclear why until Boreyko and his students made a breakthrough discovery, soon to be published in the high-impact journal ACS Nano.

In Boreyko's lab, then-undergraduate Megan Mulroe experimented with the surface of silicon chips to see how the nanoscopic topography of the surface might impact the jumping ability of condensation.

By creating and testing six different types of surfaces covered with so-called nanopillarsreminiscent of stalagmites on a cave floorMulroe found that the critical size of the jumping droplet can be fine-tuned based on the height, diameter, and pitch of the nanopillars.

"These results, correlated with a theoretical model, revealed that the bottleneck for jumping is how the droplets inflate inside of the surface after they first form," Boreyko said.

Essentially, when the nanopillars are tall and slender, the droplets formed inside and on the crevices can jump off the surface at a much smaller size, down to two micrometers. Likewise, short and stout pillars increase the size of the droplet required to jumpup to 20 micrometers in the case of Mulroe's experiment.

While the jumping droplets phenomena has been found to be the most efficient form of condensation removal, the ability to tweak the size of the droplets can allow for improved efficiency in removing condensation from surfaces.

"We expect that these findings will allow for maximizing the efficiency of jumping-droplet condensers, which could make power plants more efficient and enable robust anti-fogging and self-cleaning surfaces," Boreyko said. "The ultimate goal is for all dew droplets forming on a surface to jump off before they are even visible to the eye."

Mulroe, who was first author on the paper, conducted all of the experiments, while graduate student Farzad Ahmadi, who is pursuing a Ph.D. in Engineering Mechanics, backed up the findings with a theoretical model.

The research will be published July 31 in ACS Nano.

Explore further: Forget defrosting your car at a glacial pace: New research speeds process up tenfold

Journal reference: ACS Nano

Provided by: Virginia Tech

Jonathan Boreyko turned on the defroster in his car one cold winter morning and waited for the ice on the windshield to melt. And kept waiting.

In a completely unexpected finding, MIT researchers have discovered that tiny water droplets that form on a superhydrophobic surface, and then "jump" away from that surface, carry an electric charge. The finding could lead ...

A mathematical model that predicts how water condenses around tiny particles could help to improve chemical industrial processes, including the production of drug tablets, fertilizers and catalysts.

Sometimes, liquid drops don't drop. Instead, they climb. Using computer simulations, researchers have now shown how to induce droplets to climb stairs all by themselves.

(Phys.org) A simple new technique to form interlocking beads of water in ambient conditions could prove valuable for applications in biological sensing, membrane research and harvesting water from fog.

In a discovery that may lead to ways to prevent frost on airplane parts, condenser coils, and even windshields, a team of researchers led by Virginia Tech has used chemical micropatterns to control the growth of frost caused ...

(Phys.org)Assessing and ranking research institutes is important for awarding grants, recruiting employees, promoting institutes, and other reasons. But finding a fair and accurate method for assessing the performance ...

A newly discovered collective rattling effect in a type of crystalline semiconductor blocks most heat transfer while preserving high electrical conductivity - a rare pairing that scientists say could reduce heat buildup in ...

Los Alamos National Laboratory has produced the first known material capable of single-photon emission at room temperature and at telecommunications wavelengths. These carbon nanotube quantum light emitters may be important ...

Scientists searching for traces of drugs, bomb-making components and other chemicals often shine light on the materials they're analyzing.

Scientists at the University of Bristol have, for the first time, observed the formation of a crystal gel with particle-level resolution, allowing them to study the conditions by which these new materials form.

Science and the IT industry have high hopes for quantum computing, but descriptions of possible applications tend to be vague. Researchers at ETH Zurich have now come up with a concrete example that demonstrates what quantum ...

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

Read more:

New research could make dew droplets so small, they're invisible - Phys.Org