Salt-Enhanced CO 2 -Responsiveness of Microgels.

Here, we report a distinct mechanism for harnessing CO 2 -responsiveness through enhancing CO 2 capture ability. The finding is demonstrated on the microgels that are composed of oligo(ethylene glycol) and sulfonate moieties. Laser light scattering studies on dilute aqueous dispersion of these microgels indicated a low CO 2 -responsivity, which can be significantly enhanced by adding NaCl and other salts. This salt-enhanced CO 2 -responsiveness of microgels can be elucidated by the antipolyelectrolyte behavior and its superposition of forming cross-links physically with CO 2 as an intermediate. Further results of the filtration experiments on microgel translocation through pores suggest the feasibility of the explanation. The finding is also supported by the CO 2 capture-release experiments on the dispersion, which can reversibly absorb and desorb CO 2 .