Electron‐Donating Conjugated Microporous Polymer Membranes for Enhanced CO 2 Capture

ABSTRACT The development of conjugated microporous polymers (CMPs) with extended π ‐conjugation has positioned them as promising candidates for advanced gas separation membranes. Realizing their superior performance hinges on the rational design of their porous frameworks. Herein, we report a novel strategy to create tunable localized electric fields within CMPs by incorporating triazine rings at varied molecular positions, thereby achieving highly efficient CO 2 separation in Pebax‐based mixed matrix membranes (MMMs). As designed, the fine‐tuning of the triazine units enables the construction of an optimized donor‐ π ‐acceptor (D‐ π ‐A) electronic structure in the CMP‐PT framework. This tailored structure enhances intermolecular interactions, confers a larger dipole moment, improves coordination capability, and ultimately optimizes the microporous environment of the resultant MMM. Compared to the pristine Pebax membrane, the optimal Pebax‐CMP‐PT‐1% MMM exhibits a remarkable 83.4% enhancement in CO 2 permeability and a CO 2 /N 2 selectivity of 167.31 at 20 bar, surpassing the 2019 Robeson upper bound. This work provides a valuable strategy for the development of next‐generation high‐performance CO 2 separation membranes.