(401p) Enhancing CO2 Permeability of PDMS Nanocomposite Membranes By Incorporating Mesoporous Silica Particles Toward Efficient Gas Separation

CO₂ separation has attracted attention in various fields such as direct air capture and the production of energy resources (e.g., CO₂ methanation). Gas separation membranes have been extensively studied as a promising route toward efficient CO₂ separation and recovery, due to their ease of operation, energy efficiency, and environmental friendliness. Among gas separation membranes, mixed matrix membranes (MMMs), which combine the advantages of particulate fillers and polymer matrices, are promising materials. Polydimethylsiloxane (PDMS) has been widely studied as a matrix polymer for MMMs because of its flexibility and unique gas permeation properties, such as CO₂/N₂ selectivity. Mesoporous particles have attracted attention as fillers because they can enhance the gas permeability of MMMs in addition to improving their mechanical properties. However, the effects of mesoporous particles incorporated into PDMS membranes have not been studied in detail so far. In this study, the gas permeability and CO₂ selectivity of the PDMS incorporating mesoporous silica particles (MPs) or Stöber silica particles (SPs) with a similar size were evaluated. The mechanical properties of membranes (PDMS, PDMS/MPs, or PDMS/SPs) were characterized through tensile testing, which revealed that MPs improved the strength of membranes more effectively than SPs. As shown in the figure, PDMS/MPs membranes exhibited enhanced CO₂ permeability while CO₂ selectivity was mostly maintained. Our investigations highlight the advantages of mesoporous silica particles as fillers, which can enhance both the mechanical property and gas permeability of MMMs.