Air Date: Week of October 19, 2007

Amy Fish reports that the ingredient that gives vinegar potato chips their tangy taste may prove to be a powerful waterproof sealant for concrete.

Transcript

[SOUND OF PLASTIC BAG OPENING]

FISH: Mmm. Salt-and-vinegar potato chips. Bet you can’t eat just one. And soon, the ingredient that gives these chips their tangy taste may be used to improve our buildings.

[MUSIC: Science Note Theme]

FISH: Sodium acetate is a chemical derived from vinegar. It’s not only used to flavor chips but also to preserve food, treat leather hides, and make the heat in heating pads. And now, two university scientists in Jordan have discovered the chemical’s power as a waterproof sealant for concrete.

Concrete is the most widely used structural material in the world. But its many pores allow water and acid to seep in, which can cause the concrete to crack. Most sealants are not only expensive and short-lived—they’re often toxic to wildlife and humans.

But researchers found that sodium acetate is cheap, long lasting, and environmentally friendly when used as a sealant. Sodium acetate forms crystals that bind tightly to the pores inside concrete. The crystals absorb moisture and swell to fill the pores, which block water from entering the concrete. In dry conditions, the crystals shrink back to their original size, allowing moisture to evaporate.

So sodium acetate may help concrete become water resistant—even if it won’t help you resist that bag of chips.

That’s this week’s note on emerging science. I’m Amy Fish.