UV-crosslinked PDMS membranes with site-selective alicyclic epoxy units exhibited outstanding CO₂ permeance and selectivity. By comparing end- and side-functionalized PDMS structures, we reveal that low crosslinking density and long siloxane chains favor CO₂ diffusion. Ultrathin (~100 nm), freestanding films fabricated via photoacid-induced curing achieved a CO₂ permeance of up to 5200 GPU with a CO₂/N₂ selectivity of 11.0. This study demonstrates the potential of molecularly engineered siloxane networks for high-performance gas separation, especially in membrane-based direct air capture (m-DAC) applications.
- Shiori Hashiguchi
- Masahiko Kawata
- Masashi Kunitake
