The development of membranes that block solutes while allowing rapid water transport is of great importance. The microstructure of the membrane needs to be rationally designed at the molecular level to achieve precise molecular sieving and high water flux simultaneously. We report the design and fabrication of ultrathin, ordered conjugated-polymer-framework (CPF) films with thicknesses down to 1 nm via chemical vapour deposition and their performance as separation membranes. Our CPF membranes inherently have regular rhombic sub-nanometre (10.3 × 3.7 Å) channels, unlike membranes made of carbon nanotubes or graphene, whose separation performance depends on the alignment or stacking of materials. The optimized membrane exhibited a high water/NaCl selectivity of ∼6,900 and water permeance of ∼112 mol m−2 h−1 bar−1, and salt rejection >99.5% in high-salinity mixed-ion separations driven by osmotic pressure. Molecular dynamics simulations revealed that water molecules quickly and collectively pass through the membrane by forming a continuous three-dimensional network within the hydrophobic channels. The advent of ordered CPF provides a route towards developing carbon-based membranes for precise molecular separation.
|Original language||English (US)|
|State||Published - Aug 8 2022|
Bibliographical noteKAUST Repository Item: Exported on 2022-09-14
Acknowledged KAUST grant number(s): BAS/1/1372-01-01, OSR-2018-CARF/CCF-3079
Acknowledgements: The financial support for this work was provided by Baseline Funds (BAS/1/1372-01-01) to Y.H. from King Abdullah University of Science and Technology (KAUST), to J.J. from the A*STAR AME IRG Grant (A20E5c0092), the Ministry of Education of Singapore and the National University of Singapore (R-279-000-598-114 and R-279-000-574-114). This work was also partially supported by the National Key Research and Development Project of China (2022YFE0113800). V.T. and Y.C. are indebted to the support from the KAUST Office of Sponsored Research (OSR) under award number OSR-2018-CARF/CCF-3079. V.T. acknowledges support from KAUST Solar Center (KSC). This research used resources of the Core Laboratories of KAUST. We acknowledge helpful discussions with Q. Li and J. Wang from Soochow University; J. Yin, Y. Wan and L. Chen from KAUST, and Y. Zhang from Nanjing Tech University.
ASJC Scopus subject areas
- Mechanics of Materials
- Materials Science(all)
- Mechanical Engineering
- Condensed Matter Physics