Polymer ultrapermeability from the inefficient packing of 2D chains
Polymer ultrapermeability from the inefficient packing of 2D chains
复制标题
DOI：
10.1038/nmat4939
复制
发表时间：
2017-09-01
期刊：
影响因子：
41.2
通讯作者：
McKeown, Neil B.
中科院分区：
文献类型：
--
作者：
Rose, Ian;Bezzu, C. Grazia;McKeown, Neil B.
超渗透聚合物，如聚（三甲基甲硅烷基丙炔）（PTMSP），用于减小气体分离膜的尺寸和提高其效率的前景由于其差的选择性而仍未实现。我们报告了一种具有固有微孔性的超渗透聚合物（PIM-TMN-Trip），其选择性比PTMSP大得多。从分子模拟和实验测量中，我们发现PIM-TMN-Trip的二维（2D）链的低效堆积产生了高浓度的小（< 0.7 nm）和大（0.7-1.0 nm）微孔，前者增强了选择性，后者增强了渗透性。PIM-TMN-Trip的气体渗透率数据超过了2008年Robeson关于O-2/N-2、H-2/N-2、CO2/N-2、H-2/CH 4和CO2/CH 4的上限，证明了相关气体混合物的沼气净化和碳捕获潜力。PIM-TMN-Trip和具有三维（3D）扭曲链的结构相似的聚合物之间的比较证实，其额外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包装产生的。这种微孔聚合物链的形状定向堆积的策略可以应用于用于气体分离的其他刚性聚合物。
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 O-2/N-2, H-2/N-2, CO2/N-2, H-2/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 threedimensional (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.