Scientists manage to boil water without bubbles
A new type of nanomaterial exploits the Leidenfrost effect, in which droplets of water can skate across hot a hot surface without boiling away, to boil water without creating explosive bubbles.
A new nanomaterial vanquishes the bubbles that normally pop up with boiling, a finding that may point to ways to help prevent explosions in nuclear power plants, researchers say.Skip to next paragraph
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To understand how this material works, imagine a hot skillet. When its surface is warm, water on it will bubble. However, once the skillet gets hot enough, the water drops will skitter across its surface as they levitate on a cushion of vapor, an effect known as the Leidenfrost regime after the scientist who investigated it in 1756.
"The Leidenfrost state of a water drop is often used worldwide to gauge the temperature of a hot skillet while cooking," researcher Neelesh Patankar, a mechanical engineer at Northwestern University in Evanston, Ill., told LiveScience.
Tinkering with a surface's properties can alter the temperature at which water touching it goes from this explosive bubbling phase to the Leidenfrost regime. Making a surface hydrophobic, or water-repellant, affects how well heat gets transferred from that surface to water. Making it craggy instead of smooth also controls how heat flows from it. [Top 10 Greatest Explosions]
Scientists developed a craggy super-water-repellant coating made of nanoparticles covered with an organic, hydrophobic compound. (Nanoparticles are particles only nanometers, or billionths of a meter, in size.)
When a steel rod covered with this coating was heated, the result was a continuous film of vapor on the rod without bubbling. "One can make surfaces on which a liquid will never bubble as it starts boiling, a phenomenon that is contrary to the experience of anyone who has ever cooked," researcher Ivan Vakarelski, a physicist at King Abdullah University of Science and Technology in Saudi Arabia, told LiveScience. [See Video of the No-Bubble Boil]