HughPickens.com writes 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. Now Kenneth Chang reports at the NYT that scientists have just solved one of life's little problems — how to get that last little bit of ketchup (or glue) out of a bottle. Using a coating that makes the inside of the bottle permanently wet and slippery, glue quickly slides to the nozzle or back down to the bottom. The technology could have major environmental payoffs by reducing waste. Superhydrophobic surfaces work similar to air hockey tables. Tiny peaks and valleys on the surface create a thin layer of air between the liquid and the coating. The air decreases friction, so the liquid almost levitates above the surface, just like the hockey puck floats above the table. LiquiGlide's approach is similar, but it uses a liquid lubricant, not a gas. "What could be a solution that provides sort of universal slipperiness?" says Dr. Varanasi. "The idea we had was, Why not think about trapping a liquid in these features?" Dr. Varanasi and Mr. Smith worked out a theory to predict interactions among the surface, the lubricant and air. Essentially, the lubricant binds more strongly to the textured surface than to the liquid, and that allows the liquid to slide on a layer of lubricant instead of being pinned against the surface, and the textured surface keeps the lubricant from slipping out. "We're not defying physics, but effectively, we are," says Smith.
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