Tiny Tech 46: Slick as a Whistle

Today from the world of Tiny Tech:

Spray-on windshield coatings that repel rain are really slick: they consist of a thin film of silicone, the same rubbery material used as caulking around the home.

Silicones are hydrophobic, which means that they repel water, but some materials repel water so strongly that they are called superhydrophobic. Superhydrophobic surfaces have tiny bumps on them. Water droplets touch the surface only at the tops of the bumps, and the tiny contact area means water droplets roll off all by themselves.

Recently, a one-step method has been developed to make coatings that are superhydrophobic as well as robust and eco-friendly. The surface is heated and sprayed with silica nanoparticles, which make the tiny bumps, and simultaneously sprayed with regular hydrophobic substances including silicone and some fatty acids – which attach the nanoparticles firmly to the surface. The resulting coating remains highly superhydrophobic even after being exposed to wear, solvents, or UV light. Nifty.

So, our take-home lesson for today is that surfaces can be made superhydrophobic by roughing them up a bit, but in this case that’s a really slick thing to do!

Tiny Tech is made possible by the National Science Foundation and WUFT. To learn more about Tiny Tech, go to tinytechradio.org.

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