Thiazole Groups without Hydrogen-Bond Donors Endow PIM Membrane with High CO₂ Separation Performance

Polymers of intrinsic microporosity (PIMs) are promising membrane materials for CO₂ separation, but suffer from the trade-off effect between permeability and selectivity. And it is a challenge to design suitable groups in PIMs to improve the CO₂ separation performance. Herein, this work reports that thiazole groups without hydrogen-bond donors could endow the PIM membrane with high CO₂ permeability and separation selectivity. The abundant N atoms of the thiazole groups could provide Lewis acid-base interactions with CO₂ and significantly enhance the solubility selectivity. The lack of hydrogen-bond donors and the rigid structure of thiazole unit could inhibit the pore collapse and enhance the permeability and stability of PIM membranes. The resultant PIM membranes exhibit CO₂/N₂ and CO₂/CH₄ selectivities of 36.6 and 22, respectively, with corresponding CO₂ permeabilities of 9196 and 3801 Barrer. This work provides new insights into the rational design of functional groups for PIMs with high gas separation performance.