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

Abstract 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 Al 2 O 3 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‐Al 2 O 3 ‐6) exhibited simultaneous high thermal, mechanical, pure‐ and mixed‐gas separation, and anti‐aging properties. The O 2 /N 2 , H 2 /N 2 , and H 2 /CH 4 separation performances were adequate above the latest trade‐off lines. PIM‐1‐Al 2 O 3 ‐6 showed CO 2 and O 2 permeabilities of 624 and 188 Barrer, combined with CO 2 /CH 4 and O 2 /N 2 selectivities of 56.2 and 8.8, respectively. This significantly enhanced performance was attributed to the strong size sieving effect induced by the Al 2 O 3 deposition.