If you have ever struggled to get ketchup out of a glass jar, you'll understand why this phenomenon is annoying. Actually, it's beyond that. It's quite wasteful.
Tests by Consumer Reports in 2009 found that much of what we buy never makes it out of the container and is instead thrown away — up to a quarter of skin lotion, 16 percent of laundry detergent and 15 percent of condiments like mustard and ketchup.
A professor at the Massachusetts Institute of Technology (MIT), Kripa Varanasi, created a new company called LiquiGlide to market a product that promises to overcome this effect.
What makes it hard to get mayonnaise and toothpaste out is that they are what scientists call Bingham plastics. A Bingham plastic, named after Eugene Bingham, a chemist who described the mathematical properties, is not made of plastic; the term describes a highly viscous material that does not flow without a strong push.
Ironically, the professor actually was searching for the answer to an entirely different problem.
Dr. Varanasi did not set out to solve the problem of clingy glue and mayonnaise. Rather, he was thinking of larger-scale industrial challenges, like preventing ice formation on airplane wings and allowing more efficient pumping of crude oil and other viscous liquids. How to make a slippery surface has been an interest for many scientists and engineers with many potential uses.
When water or other liquids flow through a pipe, the layer of liquid next to the pipe wall typically sticks, not moving. Farther from the pipe wall, the liquid flows, fastest at the center. “Different layers of water are sliding past one another, and therefore there is friction, which is viscosity, and that is why you need to pump it,” said Neelesh A. Patankar, a professor of mechanical engineering at Northwestern University, who is not involved with LiquiGlide.
One simple example is when a droplet of water skitters across a hot pan that vaporizes some of the water. The droplet is riding on a layer of steam like a hovercraft, not touching the pan.
Dr. Patankar and other scientists have been investigating superhydrophobic surfaces. A hydrophobic surface repels water; a superhydrophobic surface, as one might imagine, really repels water. Inspired in part by lotus leaves, the surface of a superhydrophobic material looks rough, at least under a microscope. Water rolls up into balls, sitting on the tips of the rough surface, but mostly on air trapped between the droplet and the rough surface. The droplets roll off easily
The successful commercialization of this product could help reduce waste dramatically. There might even be potential uses in healthcare. The pictures below help show the action and how the product works.
Here is the link to the full article: http://www.nytimes.com/2015/03/24/science/with-new-nonstick-coating-the-wait-and-waste-is-over.html
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