Building with CO₂

MIT chemical engineers have come up with a material that can react with carbon dioxide from the air to expand and get stronger. As long as its surface is exposed, the carbon-based material continuously reinforces itself by capturing and converting the greenhouse gas from the air.

The new material, a polymer, is a synthetic gel-like substance that performs a chemical process similar to the one plants use to incorporate carbon dioxide from the air into their growing tissues. It could someday be used as a protective coating or a construction material such as panels of a lightweight matrix. Shipping those to a building site, where they would harden and solidify from exposure to air and sunlight, would reduce the energy and cost associated with transportation.

“This is a completely new concept in materials science,” says professor Michael Strano, who led the research with postdoc Seon-Yeong Kwak.

“Imagine a synthetic material that could grow like trees, taking the carbon from the carbon dioxide and incorporating it into the material’s backbone.” The material, which becomes stronger as it incorporates the carbon, is not yet strong enough to be used as a building material, though it might function as a crack filler or a self-repairing coating material, the researchers say.

After working out how to produce materials of this type by the ton, they’re now optimizing their properties. “Our work shows that carbon dioxide need not be purely a burden and a cost,” Strano says. “It is also an opportunity.”