Introducing amphipathic copolymer into intermediate layer to fabricate ultra-thin Pebax composite membrane for efficient CO2 capture

Pebax-based membranes have attracted intensive interest for high separation efficacy of carbon dioxide . For achieving excellent gas permeance, ultrathin membrane thickness is always the pursuit of composite membrane technology, in which controlling the interfacial property of the multi-layer remain a great challenge. Herein, we introduced an amphipathic copolymer polydimethylsiloxane (PDMS)-block-polyethylene oxide (PEO) (PDMS- b -PEO) into the intermediate layer to tune the interfacial adhesion, enabling fabrication of ultra-thin Pebax composite membrane. It was demonstrated that surface segregation of PEO segments not only suppressed formation of dense SiO x layer due to the plasma treatment on PDMS intermediate layer, but also provided extra hydrophilic sites and interfacial compatibility for subsequent Pebax selective layer coating. With the present of PDMS- b -PEO in the intermediate layer, an integrated Pebax selective layer with thickness of ∼50 nm was successfully fabricated. The resulting ultra-thin Pebax composite membrane exhibited outstanding performance with CO 2 permeance of 2142 GPU and CO 2 /N 2 selectivity of 36. The strategy of using amphipathic copolymer as intermediate layer enhanced the composite membrane integrity and simplified the plasma pre-treatment, showing great potential in developing highly permeable membrane for efficient CO 2 capture.