Tech
MIT Scientists Create Most Waterproof Surface Ever (Video)
Catherine Griffin
First Posted: Nov 21, 2013 09:58 AM EST
Scientists may have just made one of the most waterproof materials in existence. Although there's a theoretical limit on the time it takes for a water droplet to bounce away from a hydrophobic surface, researchers have discovered a way to burst through that perceived barrier. The findings could lead to a new generation of materials in the future.
"The time that the drop stays in contact with a surface is important because it controls the exchange of mass, momentum and energy between the drop and the surface," said Kripa Varanasi, one of the researchers, in a news release. "If you can get the drops to bounce faster, that can have many advantages."
According to the theoretical limit, the minimum time a bouncing droplet can stay in contact with a surface depends on the time period of oscillations in a vibrating drop, also known as the Rayleigh time. The way to achieve that minimum contact time is to minimize interaction between the water and the surface, such as by creating low-adhesion superhydrophobic surfaces.
Yet it turns out that there's a way to get past this barrier. The researchers discovered that increasing the surface interaction in a particular way can speed the process beyond the limit. To facilitate this interaction, the scientists added macroscopic features, such as ridges that break the droplet's symmetry and can serve to split it, causing it to recoil in highly irregular shapes. These ridged surfaces can have contact times that are as much as 40 percent shorter than control surfaces.
"We've demonstrated that we can use surface texture to reshape a drop as it recoils, in such a way that the overall contact time is significantly reduced," said James Bird, one of the researchers, in a news release. "The upshot is that the surface stays drier longer if this contact time is reduced, which has the potential to be useful for a variety of applications."
What applications are these? It could, potentially, be used to help prevent the buildup of ice on an airplane wing. Contact time of raindrops is critical when it comes to ice; the longer a droplet stays in contact with a surface, the greats its chances are of freezing in place. This means that the new method could be used to help reduce the amount of ice freezing on airplanes.
The findings could be huge for everything from airplanes to turbine blades in electric power plants. The method could improve efficiency and lead to materials for future applications.
The findings are published in the journal Nature.
Want to learn and see more? Check out the video below, courtesy of YouTube.
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NASA's Juno Spacecraft's Rendezvous With Jupiter's Mammoth Cyclone
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First Posted: Nov 21, 2013 09:58 AM EST
Scientists may have just made one of the most waterproof materials in existence. Although there's a theoretical limit on the time it takes for a water droplet to bounce away from a hydrophobic surface, researchers have discovered a way to burst through that perceived barrier. The findings could lead to a new generation of materials in the future.
"The time that the drop stays in contact with a surface is important because it controls the exchange of mass, momentum and energy between the drop and the surface," said Kripa Varanasi, one of the researchers, in a news release. "If you can get the drops to bounce faster, that can have many advantages."
According to the theoretical limit, the minimum time a bouncing droplet can stay in contact with a surface depends on the time period of oscillations in a vibrating drop, also known as the Rayleigh time. The way to achieve that minimum contact time is to minimize interaction between the water and the surface, such as by creating low-adhesion superhydrophobic surfaces.
Yet it turns out that there's a way to get past this barrier. The researchers discovered that increasing the surface interaction in a particular way can speed the process beyond the limit. To facilitate this interaction, the scientists added macroscopic features, such as ridges that break the droplet's symmetry and can serve to split it, causing it to recoil in highly irregular shapes. These ridged surfaces can have contact times that are as much as 40 percent shorter than control surfaces.
"We've demonstrated that we can use surface texture to reshape a drop as it recoils, in such a way that the overall contact time is significantly reduced," said James Bird, one of the researchers, in a news release. "The upshot is that the surface stays drier longer if this contact time is reduced, which has the potential to be useful for a variety of applications."
What applications are these? It could, potentially, be used to help prevent the buildup of ice on an airplane wing. Contact time of raindrops is critical when it comes to ice; the longer a droplet stays in contact with a surface, the greats its chances are of freezing in place. This means that the new method could be used to help reduce the amount of ice freezing on airplanes.
The findings could be huge for everything from airplanes to turbine blades in electric power plants. The method could improve efficiency and lead to materials for future applications.
The findings are published in the journal Nature.
Want to learn and see more? Check out the video below, courtesy of YouTube.
See Now: NASA's Juno Spacecraft's Rendezvous With Jupiter's Mammoth Cyclone