Precise Sub-Angstrom Ion Separation Using Conjugated Microporous Polymer Membranes

Polymer membranes typically possess a broad pore-size distribution that leads to much lower selectivity in ion separation when compared to membranes made of crystalline porous materials; however, they are highly desirable because of their easy processability and low cost. Herein, we demonstrate the fabrication of ion-sieving membranes based on a polycarbazole-type conjugated microporous polymer using an easy to scale-up electropolymerization strategy. The membranes exhibited high uniform sub-nanometer pores and a precisely tunable membrane thickness, yielding a high ion-sieving performance with a sub-1 A size precision. Both experimental results and molecular simulations suggested that the impressive ionsieving performance of the CMP membranes originates from their uniform and narrow pore-size distribution.

Automated summary

Polymer membranes usually have a wide pore-size distribution, resulting in lower selectivity in ion separation compared to membranes made of crystalline porous materials. However, ion-sieving membranes based on conjugated microporous polymers with high uniform sub-nanometer pores can achieve high ion-separating performance with a sub-1 A size precision, attributed to their uniform and narrow pore-size distribution.