Infiltrating molecular gatekeepers with coexisting molecular solubility and 3D-intrinsic porosity into a microporous polymer scaffold for gas separation
Infiltrating molecular gatekeepers with coexisting molecular solubility and 3D-intrinsic porosity into a microporous polymer scaffold for gas separation
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DOI：
10.1039/c9ta12028a
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发表时间：
2020-03
影响因子：
--
通讯作者：
Ji Wu;S. Japip;T. Chung
中科院分区：
文献类型：
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作者：
Ji Wu;S. Japip;T. Chung
聚合物膜中固有的宽孔径分布使其具有较少的尺寸选择性微孔区域，这可能会影响其性能，并且需要在埃级上进行具有挑战性的尺寸控制，以实现节能气体分离。在这里，我们通过一种非常规的后（膜）制造渗透（PFI）方法，成功地重塑了具有亚埃尺寸敏感性的聚合物膜中的非选择性微孔区域，该方法基于高度可调和可扩展的有机大环家族的水溶性成员，即4-磺基[4]芳烃（SCA4）。SCA4分子的小分子尺寸和附加的多个磺酸基使它们能够在常见的膜处理质子溶剂（如甲醇）中完全溶剂化，这样它们就可以分子渗透到已经制造的聚合物膜的整个微孔结构中，这些聚合物膜具有广泛的氢键或离子键位点，起着相互作用支架的作用。同时，SCA4分子具有固有的粒径筛分三维开腔，可以作为分子看门人，有效地延缓粒径不区分的气体输送，实现卓越的分子筛分性能，实现多种重要气体对的有效分离。这种超简单但非常规的PFI设计避免了长期存在的界面纳米缺陷和孔隙堵塞问题，并且通过使用其他水溶性和功能化的大环对应物来发现新的复合膜设计的可能性，也具有潜在的多样性。
The inherently broad pore-size distribution in polymer membranes endows them with fewer size-selective microporous regions which could impair their performance and would require challenging size control at the angstrom level for enabling energy-efficient gas separation. Here, we successfully remodeled the non-selective microporous regions in polymer membranes with sub-angstrom size-sensitivity via an unconventional post-(membrane) fabrication infiltration (PFI) method based on a water-soluble member of the highly tunable and expandable organic macrocyclic family, namely, 4-sulfocalix[4]arene (SCA4). The small molecular size and attached multiple sulfonic groups of SCA4 molecules have enabled their complete solvation in common membrane-treating protic solvents, like methanol, such that they could molecularly infiltrate the entire microporous structure of already fabricated polymer membranes which plays the role of an interactive scaffold with extensive hydrogen or ionic bonding sites. Meanwhile, bearing an intrinsic size-sieving 3D open cavity, SCA4 molecules could act as molecular gatekeepers that effectively retard size-indiscriminative gas transport for realizing exceptional molecular-sieving properties towards efficient separation of multiple important gas pairs. This ultra-facile yet unconventional PFI design is free from the longstanding issues of interfacial nano-defects and pore blockage and is also potentially diversifiable by using a pool of other water-soluble and functionalizable macrocyclic counterparts for uncovering new composite-membrane design possibilities.