MIT researchers have unraveled exactly how water birds like ducks and cormorants keep dry when diving in up to 100 feet of water. The secret is a combination of water-repelling oil the birds spread on their feathers during preening and the tightly interlocking structure of the feather’s barbs and barbules.
By testing and modeling the action of water on a feather, they were able to see that the bird’s plumage doesn’t totally repel the liquid and can actually get wet when immersed. But the bird’s preening oil increases the energy needed for water to wet the feather. When the animal leaves the water, the wetting is reversed and the water is ejected off the feather.
“If a feather gets wet, there is no need for it to dry out, in the traditional sense of evaporation,” says Robert Cohen, a chemical engineering professor on the research team. “It can dry by directly ejecting the water from its structure, as the pressure is reduced as it comes back up from its dive.”
Coating Makes Steel Tougher, Keeps Microbes From Sticking
More and more objects are getting superhydrophobic coatings that make liquids bounce right off. Surfaces with complex nanoscopic structures that prevent wetting will soon be deployed on wind turbine blades and aircraft wings to prevent ice from sticking, and even concrete is being doped with superhydrophobic compounds to help it last decades longer.
Much still needs to be done, though, to strengthen these coatings because any damage can remove the ability to repel liquids. Such an advance is hugely important since there are potentially life-saving healthcare applications if this hurdle could be overcome with a stable, nontoxic coating for steel. Just imagine if implants, scalpels and other tools used on patients had a surface impossible for infection-causing microbes to cling to.
Now, Joanna Aizenberg and her colleagues at Harvard’s Wyss Institute for Biologically Inspired Engineering have demonstrated a possible solution. They’ve been able to coat stainless steel with nanoporous tungsten oxide, which repels all liquids. What’s more, the surface is extremely tough, maintaining superhydrophobicity even after being scratched with sharp steel objects and diamond.
Happy MariMarch, everyone! This Saturday we will be unveiling our first Mob Arena, Rabbit Arena, an arena loosely based on Alice in Wonderland! We will be having a party at 8pm EST (5pm PST) Saturday to celebrate the grand opening, and we will be giving away cool and unique prizes for everyone who plays the arena! Come and play with us! Click the read more below for extra info about the plugin and what you can find in the Arena. Thank you for playing MarimoCraft!
Engineers report they have created a surface like a Teflon pan on steroids that can repel all liquids.
For years, researchers have been working on coatings that, like lotus leaves, don’t get wet when a liquid falls on them. Such coatings are integral in industrial and other applications where wet surfaces can impact performance or cause corrosion to begin. They are also being pursued for medical applications to prevent bacteria from building up on devices and other surfaces.
Engineered water repellant “superhydrophobic” and oil repellant “superoleophobic” surfaces use textures or chemical means to minimize the surface’s contact with a liquid drop. This forces the droplet to stay intact through the cohesive force of its own surface tension. Up until now, though, even the most water and oil resistant surfaces could still get wet when liquids with extremely low surface tension like certain industrial solvents made contact.
Engineers can now create materials that repel liquids so well they’re called superhydrophobic, i.e. they have a serious water phobia. With funding from the National Science Foundation (NSF), this booming area of research has the potential to benefit society in a big way.
Txch This Week: Control A Living Avatar And 3-D-Printed Face Transplants
by Jared Kershner
This week on Txchnologist, engineers have reported that they created a surface that can repel all liquids, like a Teflon pan on steroids. Made of a structured silicon dioxide, the coating is covered with microscopic nailheads that hold up any liquid while distributing its weight through many contact points. Liquids sit on a cushion that is 95 percent air, and the fluid’s surface tension holds it together to roll over the surface without wetting it.
MIT engineers have developed a new computer model that allows them to design the most complex 3-D shapes ever created out of DNA, including intricate rings, bowls, and geometric cages. The program works by stapling together snips of DNA in predictable ways to create a host of geometries. The information in the DNA, instead of being used for replication or other biological functions, is used as building materials to piece together these nanoscopic assemblies.
Now we’re bringing you the news and trends we’ve been following this week in the world of science, technology and innovation.