The promise of ultrapermeable polymers, such as poly(trimethylsilylpropyne) (PTMSP), for reducing the size and increasing the efficiency of membranes for gas separations remains unfulfilled due to their poor selectivity. We report an ultrapermeable polymer of intrinsic microporosity (PIM-TMN-Trip) that is substantially more selective than PTMSP. From molecular simulations and experimental measurement we find that the inefficient packing of the two-dimensional (2D) chains of PIM-TMN-Trip generates a high concentration of both small (<0.7 nm) and large (0.7–1.0 nm) micropores, the former enhancing selectivity and the latter permeability. Gas permeability data for PIM-TMN-Trip surpass the 2008 Robeson upper bounds for O₂/N₂, H₂/N₂, CO₂/N₂, H₂/CH₄ and CO₂/CH₄, with the potential for biogas purification and carbon capture demonstrated for relevant gas mixtures. Comparisons between PIM-TMN-Trip and structurally similar polymers with three-dimensional (3D) contorted chains confirm that its additional intrinsic microporosity is generated from the awkward packing of its 2D polymer chains in a 3D amorphous solid. This strategy of shape-directed packing of chains of microporous polymers may be applied to other rigid polymers for gas separations.

中文翻译：

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二维链效率低下导致的聚合物超渗透性

诸如聚（三甲基甲硅烷基丙炔）（PTMSP）之类的超渗透性聚合物由于其选择性差而无法实现减小尺寸和提高气体分离膜效率的承诺。我们报告了固有微孔性（PIM-TMN-Trip）的超渗透性聚合物，其本质上比PTMSP更具选择性。通过分子模拟和实验测量，我们发现PIM-TMN-Trip的二维（2D）链效率低下，产生了高浓度的小孔（<0.7  nm）和大孔（0.7-1.0  nm），前者提高选择性，后者提高渗透率。PIM-TMN-Trip的气体渗透率数据超过了2008年Robeson的O ₂ / N ₂，H ₂ / N上限参照图₂，CO ₂ / N ₂，H ₂ / CH ₄和CO ₂ / CH ₄，对于相关的气体混合物显示了沼气净化和碳捕获的潜力。PIM-TMN-Trip与具有三维扭曲（3D）扭曲链的结构相似的聚合物之间的比较证实，其附加的固有微孔性是由其2D聚合物链在3D无定形固体中的笨拙堆积所产生的。这种微孔聚合物链的形状定向堆积的策略可以应用于其他刚性聚合物进行气体分离。