Microporous polymeric composite membranes with advanced film properties: Pore intercalation yields excellent CO₂ separation performance

Polymers of intrinsic microporosity (PIMs) are revolutionary gas separation materials because of their ultra-high permeability, but suffer from low gas pair selectivity (for example CO₂/N₂) and poor durability due to brittleness. Here we present a simple solution to these problems by blending PIM-1 with compatible polymer blend composed of PIM-1 and an ether side chain polyphosphazene (MEEP80), which possesses better mechanical flexibility and higher CO₂/N₂ selectivity than the native PIM-1 while maintaining high CO₂ permeability. Under mixed gas test conditions, a blend of 25 wt% MEEP80 in PIM-1 has a CO₂ permeability of 2440 barrer and a CO₂/N₂ selectivity of 39 under mixed gas testing conditions, putting it among the best known polymers for CO₂/N₂ separation.