Center for Membrane and Water Science and Technology, Zhejiang University of Technology, Hangzhou, 310014, China.
Beijing Key Laboratory for Green Catalysis and Separation, Department of Environmental and Chemical Engineering, Beijing University of Technology, Beijing, 100124, China.
Adv Mater. 2021 Sep;33(38):e2102292. doi: 10.1002/adma.202102292. Epub 2021 Aug 4.
Nanofluidics derived from low-dimensional nanosheets and protein nanochannels are crucial for advanced catalysis, sensing, and separation. However, polymer nanofluidics is halted by complicated preparation and miniaturized sizes. This work reports the bottom-up synthesis of modular nanofluidics by confined growth of ultrathin metal-organic frameworks (MOFs) in a polymer membrane consisting of zwitterionic dopamine nanoparticles (ZNPs). The confined growth of the MOFs on the ZNPs reduces the chain entanglement between the ZNPs, leading to stiff interfacial channels enhancing the nanofluidic transport of water molecules through the membrane. As such, the water permeability and solute selectivity of MOF@ZNPM are one magnitude improved, leading to a record-high performance among all polymer nanofiltration membranes. Both the experimental work and the molecular dynamics simulations confirm that the water transport is shifted from high-friction-resistance conventional viscous flow to ultrafast nanofluidic flow as a result of rigid and continuous nanochannels in MOF@ZNPM.
基于低维纳米片和蛋白质纳米通道的纳流体制备对于先进的催化、传感和分离至关重要。然而，聚合物纳流体制备过程复杂且尺寸较小，限制了其发展。本工作通过在由两性离子多巴胺纳米颗粒（ZNPs）组成的聚合物膜中限制超薄金属有机骨架（MOFs）的生长，实现了模块化纳流体制备。MOFs 在 ZNPs 上的限制生长减少了 ZNPs 之间的链缠结，形成刚性界面通道，从而增强了水分子通过膜的纳流传输。因此，MOF@ZNPM 的水透过率和溶质选择性提高了一个数量级，使其在所有聚合物纳滤膜中具有最高的性能。实验工作和分子动力学模拟均证实，由于 MOF@ZNPM 中存在刚性且连续的纳米通道，水传输从高摩擦阻力的传统粘性流转变为超快纳流。
