CO2-Responsive Polymers for Membrane Applications: Synthesis and Adsorption Performance

The pressing need to address climate change has driven research into novel CO₂ capture materials. Here, the synthesis of CO₂-responsive diblock copolymers, i.e., poly(N-[3-(dimethylamino)propyl]-acrylamide)-b-poly(methyl methacrylate) (PDMAPAm-b-PMMA) through a two-step RAFT polymerization process, as well as the use of the synthesized diblock copolymer as a membrane for CO₂ capture were investigated. The resulting diblock copolymer features distinct segments with different properties. The PDMAPAm segment offers CO₂-responsive characteristics, while the PMMA segment provides mechanical stability. The gas transport properties of the fabricated thin-film composite membrane composed of PDMAPAm-b-PMMA or PDMAPAm and polydimethylsiloxane with a gutter layer were measured and the CO₂ adsorption behavior of both PDMAPAm and PDMAPAm-b-PMMA was evaluated. The copolymer exhibits responsiveness to CO₂ and can be customized for use in the fabrication of membranes and membrane adsorbers for direct air capture technologies.