Solvent-Responsive and Switchable Nanofiltration Membranes based on Hypercrosslinked Polymers with Permanent Porosity
Solvent-Responsive and Switchable Nanofiltration Membranes based on Hypercrosslinked Polymers with Permanent Porosity
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DOI：
10.1002/cnma.201800036
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发表时间：
2018-06
期刊：
影响因子：
9.9
通讯作者：
K. Schute;Felicitas Jansen;M. Rose
中科院分区：
文献类型：
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作者：
K. Schute;Felicitas Jansen;M. Rose
多孔有机骨架材料如超交联聚合物（HCP）在多种溶剂中显示出高的化学稳定性和动态行为，而它们的孔性质在混合基质膜（MMM）中显示出巨大的应用潜力。然而，它们在MMM中作为多孔填料的影响，特别是在液相过滤中的应用仍然未被开发。在此，我们展示了一种基于HCP的MMM，用于通过纳滤（NF）在液相中进行分子分离。取决于溶剂，膜通过收缩或溶胀改变其自由体积分数。与此相关，孔径也会受到影响，因此提供了可调的渗透率和分子截止值。孔体积和尺寸的减小直接关系到NF性能的改善，而体积的增加则完全降低了NF性能。非凡的柔韧性和高度交联确保了永久的多孔性，并使动态行为完全可逆。因此，能够实现NF性质的溶剂响应性“开”和“关”切换，并且实验证明了这一点。总的来说，这提供了关于膜污染和再生以及通过可调分离性能抑制膜衍生过程中孔堵塞的替代策略。
Porous organic framework materials such as hypercrosslinked polymers (HCP) show a high chemical stability and dynamic behavior in a variety of solvents while their pore properties exhibit great potential for mixed matrix membrane (MMM) applications. However, their influence as porous filler in MMMs, especially for applications in liquid‐phase filtration is still unexploited. Herein, we demonstrate an HCP‐based MMM for molecular separation in the liquid phase by nanofiltration (NF). Depending on the solvent, the membrane changes its fractional free volume by shrinking or swelling. In connection to that, the pore size is also influenced, hence, providing a tunable permeance and molecular cut‐off. The reduction of the pore volume and size directly correlates to the improvement of the NF performance, while the volume increase completely diminishes it. The extraordinary flexibility and high degree of crosslinking assure permanent porosity and render the dynamic behavior fully reversible. Thereby, a solvent‐responsive “on” and “off” switching of the NF properties is enabled and was experimentally proven. Overall, this provides alternative strategies regarding the fouling and regeneration of membranes as well as the inhibition of pore blocking in membrane‐derived processes by a tunable separation performance.