Tröger's base (TB) polymer of intrinsic microporosity has aroused increasing attention in various membrane-mediated gas separations. Herein we report macromolecular engineering to tune the microporosity of Tröger's base polymer of intrinsic microporosity (TB-PIM) via ionization for highly permselective helium recovery from natural gas. We reveal that the ionization of TB-PIM tightens polymer chain-packing, leading to dramatic enhancement of gas selectivities. Consequently, the ionic ITB-PIM membranes display the He/CH₄ selectivity increments in the range of 34–158% and impressively high gas selectivities for helium recovery (i.e., α(He/CH₄) = 246; α(He/N₂) = 229). Due to the enhancement of inter-chain interactions induced by electrostatic interaction, the ITB-PIM membranes exhibit enhanced plasticization resistance compared to the pristine TB-PIM membranes. Notably, the ITB-Trip membrane showed excellent low-temperature gas separation performance with a He permeance of 3162 Barrer and He/CH₄ selectivity of 38.5 at −30 °C, far beyond the 2008 upper bound. It is also proved that the microporosity and gas separation performance of ITB-PIM membranes is highly tailorable by adjusting the TB monomer structure. The facile functionalization method, highly diverse tunability, and excellent gas separation performance render the ITB-PIM membranes promising for helium recovery from natural gas.

Tröger 基 (TB) 聚合物的固有微孔性在各种膜介导的气体分离中引起了越来越多的关注。在此，我们报告了大分子工程，通过电离调整 Tröger 固有微孔隙率基础聚合物 (TB-PIM) 的微孔隙率，从而从天然气中回收高选择性渗透的氦气。我们发现 TB-PIM 的电离会收紧聚合物链堆积，从而显着提高气体选择性。因此，离子 ITB-PIM 膜显示出 34-158% 范围内的 He/CH ₄选择性增量和令人印象深刻的高气体选择性以回收氦气（即 α(He/CH ₄ ) = 246；α(He/N _2个) = 229). 由于静电相互作用引起的链间相互作用的增强，与原始 TB-PIM 膜相比，ITB-PIM 膜表现出增强的抗塑化性。值得注意的是，ITB-Trip 膜显示出出色的低温气体分离性能，在 -30 °C 时 He 渗透率为 3162 Barrer，He/CH ₄选择性为 38.5，远高于 2008 年的上限。还证明了通过调整TB单体结构，ITB-PIM膜的微孔率和气体分离性能具有高度可定制性。简便的功能化方法、高度多样化的可调性和出色的气体分离性能使 ITB-PIM 膜有望用于从天然气中回收氦气。