Eliasson Kasper, Jiang Fanfan, Åhlén Michelle, Strømme Maria, Xu Chao
Division of Nanotechnology and Functional Materials, Department of Materials Science and Engineering, Ångström Laboratory, Uppsala University, SE-752 37 Uppsala, Sweden.
State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, 211800 Nanjing, China.
J Am Chem Soc. 2025 Aug 13;147(32):29271-29281. doi: 10.1021/jacs.5c08788. Epub 2025 Jul 30.
Covalent organic framework (COF) membranes hold significant promise for applications in separation, catalysis, and energy conversion; however, their industrial adoption has been hindered by the lack of scalable and efficient fabrication methods. Here, we present a fast, versatile, and broadly applicable strategy for fabricating free-standing and flexible COF membranes by casting precursor suspensions, followed by heat treatment under controlled humidity. This approach enables the fabrication of COF membranes with lateral dimensions up to several square decimeters and thicknesses that are tunable down to submicron levels within 1 h. It demonstrates remarkable versatility for producing a family of ketoenamine-linked COF membranes through the condensation of 1,3,5-triformylphloroglucinol with various amine monomers differing in length, side groups, and geometry. The resulting crack-free COF membranes exhibit high mechanical strength, with ultimate tensile strength up to 60 MPa and Young's modulus up to 1.7 GPa, as well as exceptionally high porosity, with Brunauer-Emmett-Teller (BET) surface areas reaching up to 2226 m g. More importantly, the morphology, porosity, and crystallinity of the membranes can be finely tuned by modulating the heating conditions. The membranes with optimized microstructures demonstrate excellent separation performance, achieving over 99% rejection in nanofiltration of aqueous dye solutions, and a separation factor of 11 with an H permeance of 2857 GPU in H/CO gas separation. This approach provides a scalable and effective pathway toward large-scale COF membrane manufacturing for advanced molecular separations and other membrane-based technologies.
共价有机框架（COF）膜在分离、催化和能量转换应用方面具有巨大潜力；然而，缺乏可扩展且高效的制备方法阻碍了它们在工业上的应用。在此，我们提出了一种快速、通用且广泛适用的策略，通过浇铸前驱体悬浮液，然后在可控湿度下进行热处理，来制备独立且柔性的COF膜。这种方法能够在1小时内制备出横向尺寸达数平方分米、厚度可调控至亚微米级别的COF膜。通过1,3,5-三甲酰基间苯三酚与各种长度、侧基和几何形状不同的胺单体缩合，该方法在制备一系列酮烯胺连接的COF膜方面展示出显著的通用性。所得的无裂纹COF膜具有高机械强度，极限拉伸强度高达60 MPa，杨氏模量高达1.7 GPa，以及极高的孔隙率，布鲁诺尔-埃米特-泰勒（BET）表面积高达2226 m²/g。更重要的是，通过调节加热条件可以对膜的形态、孔隙率和结晶度进行精细调控。具有优化微观结构的膜表现出优异的分离性能，在水性染料溶液的纳滤中截留率超过99%，在H₂/CO₂气体分离中分离因子为11，H₂渗透率为2857 GPU。这种方法为大规模制造用于先进分子分离和其他基于膜的技术的COF膜提供了一条可扩展且有效的途径。
