Highly Permeable Oligo(ethylene oxide)-co-poly(dimethylsiloxane) Membranes for Carbon Dioxide Separation

Abstract

A series of cross-linked, freestanding oligo(ethylene oxide)-co-(polydimethylsiloxane-norbornene) membranes with varied composition is synthesized via in situ ring-opening metathesis polymerization. These membranes show remarkably high CO2 permeabilities (3400 Barrer) and their separation performance approaches the Robeson upper bound. The excellent permeability of these copolymer membranes provides great potential for real-world applications where enormous volumes of gases must be separated. The gas transport properties of these films are found to be directly proportional to oligo(ethylene oxide) content incorporation, which stems from the increased solubility selectivity change within the copolymer matrix. This work provides a systematic study of how gas separation performance in rubbery membranes can be enhanced by tuning the CO2-philicity of their constituent monomeric subunits.