New material pulls carbon from the air for self-repair
With the recent report from the Intergovernmental Panel on Climate Change (IPCC) painting a pretty alarming picture of the not-too-distant future, it's not enough to reduce our carbon output – we need to actively remove some from the atmosphere. Direct Air Capture systems could do the really heavy lifting, but on a smaller scale MIT engineers have developed a new material that can suck carbon out of the air and use it to get stronger or patch itself up.
The material in question is a hydrogel matrix, made of an aminopropyl methacrylamide (APMA) and glucose polymer, and an enzyme known as glucose oxidase. But the active ingredients are chloroplasts, the bits of plant cells that catalyze light during photosynthesis. In this case they were extracted from spinach leaves and embedded into the hydrogel, where they get to work plucking carbon out of the ambient air, turning it into a solid form and using that to "build" itself.
"Imagine a synthetic material that could grow like trees, taking the carbon from the carbon dioxide and incorporating it into the material's backbone," says Michael Strano, corresponding author of the study.
This ability gives the material a few advantages. Along with removing carbon from the air, it can also make for a surface that automatically patches up any cracks, scuffs and scratches that form on it. Plus, it could make transporting building materials easier – it starts off light for shipping, then once it arrives it bulks itself up to become stronger.
"Our work shows that carbon dioxide need not be purely a burden and a cost," says Strano. "It is also an opportunity in this respect. There's carbon everywhere. We build the world with carbon. Humans are made of carbon. Making a material that can access the abundant carbon all around us is a significant opportunity for materials science. In this way, our work is about making materials that are not just carbon neutral, but carbon negative."
Promising as it seems so far, there are still plenty of hurdles to leap over before this proof-of-concept material could hit the market. For one, the chloroplasts only survive for a few hours once removed from the plant, so the team is working to develop synthetic versions that do the same job for longer. More work will also need to be done to make the material strong enough to build with, but in its current form it could work as a self-healing coating or gap-filler.
The research was published in the journal Advanced Materials.