CO2 capture-induced polymer complexes

Intensified global warming is the most pressing worldwide issue. Effective capture of CO2 facilitates the resolution of this problem. This paper provides a novel and simple method to capture and store CO2 as carbonic acid in polymer complexes by combining an acid-base reaction and electrostatic ion exchange. This method is energy-savings without heating and a long reaction time and uses harmless polymers containing no metals except Na. A polymer supporting 2,2,6,6-tetramethylpiperidine, a hindered amine, captured carbonic acid in water by introducing gaseous CO2. The polymer containing the tetramethylpiperidinium bicarbonate produced insoluble complexes with poly(sodium 4-styrenesulfonate) (PSS) through their ion exchange. The complexes with a low-molecular-weight PSS were reversibly dissociated by introducing N 2 , whereas those with a high-molecular weight PSS stored the carbonic acid in their tight structures. The complexes in an aqueous methanol solution were irreversible, being independent of the PSS chain length. The PSS chain length produced a difference in the morphology of the complex aggregates; the short PSS produced linear and rigid aggregates with a ribbon-like morphology. In contrast, the long PSS provided aggregates with a planar morphology. These findings indicated that the capture and storage of carbonic acid in the polymer complexes are helpful not only in preserving the marine ecosystem from ocean acidification, but also in creating new materials composed of carbonic acid.