Liu Yuhao, Li Wei, Yuan Chen, Jia Lei, Liu Yan, Huang Aisheng, Cui Yong
School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules and State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai, 200240, China), .
Shanghai Key Laboratory of Green Chemistry and Chemical Processes, Department of Chemistry, East China Normal University, Shanghai, 200241, China), .
Angew Chem Int Ed Engl. 2022 Jan 10;61(2):e202113348. doi: 10.1002/anie.202113348. Epub 2021 Nov 25.
Covalent organic frameworks (COFs) hold great potentials for addressing the challenge of highly efficient oil-water separation, but they are restricted by the poor wettability and processability as crystalline membranes. Here we report the design and synthesis of two-dimensional (2D) robust COFs with controllable hydrophobicity and processability, allowing the COF layers to be directly grown on the support surfaces. Three 2D COFs with AA or ABC stacking are prepared by condensation of triamines with fluorine and/or isopropyl groups and perfluorodialdehyde. They all show excellent tolerance to water, acid, and base, with water contact angles (CA) of 111.5-145.8°. The two COFs with isopropyl and fluorine mixtures can grow as a coating on a stainless-steel net (SSN) substrate, whereas the one with only fluorine substituents cannot. The superhydrophobic COF@SSN coating with water CA of up to 150.1° displays high water-resistance and self-cleaning properties, enabling high oil-water separation performances with an efficiency of over 99.5 % and a permeation flux of 2.84×10 L m h , which are among the highest values reported for state-of-the-art membranes.
共价有机框架材料（COFs）在应对高效油水分离挑战方面具有巨大潜力，但作为结晶膜，它们受到润湿性和可加工性差的限制。在此，我们报告了具有可控疏水性和可加工性的二维（2D）坚固COFs的设计与合成，使COF层能够直接生长在支撑表面上。通过三胺与含氟和/或异丙基的基团以及全氟二醛缩合制备了三种具有AA或ABC堆积的二维COF。它们都表现出对水、酸和碱的优异耐受性，水接触角（CA）为111.5 - 145.8°。两种含有异丙基和氟混合物的COF可以作为涂层生长在不锈钢网（SSN）基材上，而仅含氟取代基的COF则不能。水接触角高达150.1°的超疏水COF@SSN涂层具有高耐水性和自清洁性能，实现了高效油水分离性能，效率超过99.5%，渗透通量为2.84×10 L m h ，这是目前报道的最先进膜的最高值之一。
