Highly Permeable CO2-Philic Polymer Membranes for Carbon Capture

Most of the world’s energy is presently derived from the burning of fossil fuels, which releases vast quantities of carbon dioxide (CO₂) into the environment and results in undesirable climate change. Practical and cost-efficient methods of CO₂ separation and capture would thus solve one of the most challenging problems today. This presentation summarizes our effort on the development of novel polymer membranes functionalized with CO₂-philic groups for high flux CO₂ separation. Our strategy focuses on tuning solubility selectivity in addition to diffusivity selectivity for achieving high permeability membranes combined with good selectivity. Various synthetic techniques including ROMP, thiol-ene click reaction, and post functionalization were used and the careful design permits to prepare well-defined novel highly permeable polymers containing CO₂-philic groups. This study demonstrated the addition of CO₂-philic groups (e.g. amidoxime and PEO) significantly increased the solubility selectivity of CO₂ over N₂. The membrane performance is also highly dependent on the balance of gas/functional group interaction, intra/inter- molecular interaction (H-bonding etc.) of membrane, packing, and polymer dynamics (degree of crosslinking). Tuning the balance of the interaction and dynamics enables to achieve the CO₂ separation performance over the Robeson upper bound, e.g. CO₂ permeability 6800 Barrer and CO₂/N₂ selectivity 19, or CO₂ permeability 930 Barrer and CO₂/N₂ selectivity 38. The structure-property relationships especially on CO₂ uptake, CO₂ and N₂ permeability, CO₂/N₂ selectivity to the polymer structure, as well as the effort on the selective layer coating will be discussed.