Surfactant‐Mediated Self‐Assembly of Highly Oriented ZIF‐8 Nanosheet Membranes for Propylene/Propane Separation

An oriented seed layer is crucial for the preparation of the oriented molecular sieving membrane via secondary growth. However, achieving a highly ordered seed layer remains a significant challenge due to the “coffee‐ring” effect during seeds deposition. Herein, we reported a surfactant‐mediated self‐assembly strategy for the preparation of highly ordered and oriented ZIF‐8 nanosheet layers. The ZIF‐8 nanosheets were arranged side‐by‐side and stacked layer‐by‐layer on the substrate, thus forming an oriented ZIF‐8 nanosheet layer. This ZIF‐8 nanosheet layer is readily transformed into an oriented ZIF‐8 membrane through a simple polymer‐sealing process. The resulting ZIF‐8 nanosheet membrane exhibits a high C 3 H 6 /C 3 H 8 selectivity of 36.9 and remarkably high C 3 H 6 permeance of 5.1 × 10 −8 mol m −2 s −1 Pa −1 . Moreover, this surfactant‐mediated self‐assembly strategy can also be extended to achieve ordered arrangements of other nanosheets such as ZIF‐L and Dia(Zn) on various substrates, demonstrating the universal applicability of our approach.