CO2-Philic Polymer Membranes for High Flux CO2 Separation

The vast majority 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 and post functionalization were used and the careful design permits to prepare well-defined novel high 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. Tuning the balance of the interaction enables to achieve the CO₂ separation performance over the Robeson upper bound, e.g. CO₂ permeability 3000-8000 Barrer and CO₂/N₂ selectivity 18-20. The structure-property relationships especially on CO₂ uptake, CO₂ and N₂ permeability, CO₂/N₂ selectivity to the polymer structure will be discussed.