An integrated materials approach to ultrapermeable and ultraselective CO 2 polymer membranes

Abstract

Advances in membrane technologies that combine greatly improved carbon dioxide (CO 2 ) separation efficacy with low costs, facile fabrication, feasible upscaling, and mechanical robustness are needed to help mitigate global climate change. We introduce a hybrid-integrated membrane strategy wherein a high-permeability thin film is chemically functionalized with a patchy CO 2 -philic grafted chain surface layer. A high-solubility mechanism enriches the concentration of CO 2 in the surface layer hydrated by water vapor naturally present in target gas streams, followed by fast CO 2 transport through a highly permeable (but low-selectivity) polymer substrate. Analytical methods confirm the existence of an amine surface layer. Integrated multilayer membranes prepared in this way are not diffusion limited and retain much of their high CO 2 permeability, and their CO 2 selectivity is concurrently increased in some cases by more than ~150-fold.