Electropolymerization of Molecular-Sieving Polythiophene Membranes for H₂ Separation

Membrane technologies that do not rely on heat for industrial gas separation would lower global energy cost. While polymeric, inorganic, and mixed-matrix separation membranes have been rapidly developed, the bottleneck is balancing the processability, selectivity, and permeability. Reported here is a softness adjustment of rigid networks (SARs) strategy to produce flexible, stand-alone, and molecular-sieving membranes by electropolymerization. Here, 14 membranes were rationally designed and synthesized and their gas separation ability and mechanical performance were studied. The separation performance of the membranes for H₂/CO₂, H₂/N₂, and H₂/CH₄ can exceed the Robeson upper bound, among which, H₂/CO₂ separation selectivity reaches 50 with 626 Barrer of H₂ permeability. The long-term and chemical stability tests demonstrate their potential for industrial applications. This simple, scalable, and cost-effective strategy holds promise for the design other polymers for key energy-intensive separations.