State Key Laboratory of Luminescent Materials and Devices & South China Advanced Institute for Soft Matter Science and Technology, South China University of Technology, Guangzhou, 510640, P. R. China.
Macromol Rapid Commun. 2023 Dec;44(24):e2300477. doi: 10.1002/marc.202300477. Epub 2023 Oct 17.
The emergence of polymers with intrinsic microporosity provides solutions for flexible gas separation membranes with both high gas permeability and selectivity. However, their applications are significantly hindered by the costly synthetic efforts, limited availability of chemical systems, and narrow window of microporosity sizes. Herein, flexible mixed matrix membranes with tunable intrinsic microporosity can be facilely fabricated from the coordination assembly of polymer brushes and coordination nanocages. Polymer brushes bearing isophthalic acid side groups can coordinate with Cu to assemble into polymer networks crosslinked by 2 nm nanocages. The semi-flexible feature of the polymer brush and the high crosslinking density of the network prevent the network from collapsing during solvent removal and the obtained aerogels demonstrate hierarchical structure with dual porosity from the crosslinked polymer network and coordination nanocage, respectively. The porosity can be facilely tuned via the amount of Cu by regulating the network crosslinking density and nanocage loadings, and finally, optimized gas separation that surpasses Robeson upper bound for H /CO can be achieved. The coordination-driven assembly protocol paves a new avenue for the cost-effective synthesis of polymers with intrinsic microporosity and the fabrication of flexible gas separation membranes.
具有本征微孔的聚合物的出现为具有高气体渗透性和选择性的柔性气体分离膜提供了解决方案。然而，它们的应用受到昂贵的合成努力、有限的化学体系可用性以及微孔尺寸狭窄窗口的显著限制。在此，通过聚合物刷和配位纳米笼的配位组装，可以简便地制备具有可调本征微孔的柔性混合基质膜。带有间苯二甲酸侧基的聚合物刷可以与 Cu 配位，组装成由 2nm 纳米笼交联的聚合物网络。聚合物刷的半柔性特征和网络的高交联密度可防止网络在去除溶剂时坍塌，所得气凝胶分别具有由交联聚合物网络和配位纳米笼形成的具有双重孔隙率的分级结构。通过调节网络交联密度和纳米笼负载量，可以轻松调节孔隙率，最终可以实现超过 H/CO 的 Robeson 上限的优化气体分离。配位驱动的组装方案为具有本征微孔的聚合物的经济高效合成和柔性气体分离膜的制备开辟了新途径。
