Tailoring the Microporosity of Polymers of Intrinsic Microporosity for Advanced Gas Separation by Atomic Layer Deposition

Tailoring the microporosity of intrinsically microporous polymers at the atomic level is one of the biggest challenges in achieving high-performance polymeric gas separation membranes. In this study, for the first time, the Al₂O₃ atomic layer deposition (ALD) technique was used to modify the microporosity of a typical polymer of intrinsic microporosity (PIM-1) at the atomic level. PIM-1 with six ALD cycles (PIM-1-Al₂O₃-6) exhibited simultaneous high thermal, mechanical, pure- and mixed-gas separation, and anti-aging properties. The O₂/N₂, H₂/N₂, and H₂/CH₄ separation performances were adequate above the latest trade-off lines. PIM-1-Al₂O₃-6 showed CO₂ and O₂ permeabilities of 624 and 188 Barrer, combined with CO₂/CH₄ and O₂/N₂ selectivities of 56.2 and 8.8, respectively. This significantly enhanced performance was attributed to the strong size sieving effect induced by the Al₂O₃ deposition.