Polymer Passes Up N₂ For CO₂

Although scientists have come up with many materials for soaking up excess carbon dioxide, most have drawbacks that keep them from ever leaving the lab. In the case of organic nanoporous polymers, the problem is that as temperatures rise, these materials have trouble differentiating CO₂ from nitrogen gas. Now a team led by Cafer T. Yavuz and Ali Coskun of Korea Advanced Institute of Science & Technology has come up with polymers that get better at separating CO₂ from N₂ as they get hotter (Nat. Commun., DOI: 10.1038/ncomms2359). The nanoporous polymers feature aromatic groups bridged by azo units. The researchers believe that these azo units make the materials N₂-phobic. “Any gas separations that require the efficient exclusion of N₂ gas would do well to employ azo units in the sorbent chemistry,” they note. The polymers are stable up to 350 °C in air and can also survive a boiling water bath for a week. They are particularly good at keeping out N₂ under typical industrial plant gas-discharge temperatures of above 40 °C.