Insect-Inspired Strategy for Conferring Reversible, High Responsivity on Microgels to Dilute-Source CO₂

We described an insect-inspired strategy for conferring reversible, high responsivity on polymer microgels to dilute-source CO₂ (≤5000 ppm in gas mixtures). This is demonstrated on oligo(ethylene oxide)-based microgels that contain tertiary amines on the polymer chains with proper organic small molecular carbonates in the polymer-solvent system. Similar to the synergistic contribution of the CO₂ receptor subunits in mosquitoes for CO₂ response, laser light scattering and related studies indicated that the CO₂-response of the microgels in terms of the volume changes works through the coordination of different functional moieties in the system, making it different from the conventional CO₂-response mechanism. While this pushes the lower response threshold of CO₂ concentration down to ca. 1000 ppm, this unique strategy can also satisfy the urge to achieve both effective CO₂ capture and facile CO₂ release, making it possible to couple the detection with the capture and utilization of indoor excess CO₂.