Soluble polymeric metal-organic frameworks toward crystalline membranes for efficient cation separation

Abstract

Metal-organic frameworks (MOFs) with ordered and uniform-sized channels show promising applications in ion separations. The lack of solution processability of MOFs restrains them from processing for diverse membrane-based separations. Herein, we report soluble polymeric MOFs (polyMOFs) with versatile linkers obtained by Williamson ether polycondensation. The polyligands lead to crystalline and porous MOFs with a high solubility in N-methyl pyrrolidone for membrane fabrication via a casting method. The designed polyMOFs maintain their framework structure after several dissolution and precipitation cycles. The polyMOF membranes exhibit an outstanding cation separation performance because of the nanopore sieving effect. Our findings provide a platform for the facile construction of MOF membranes by rational design of soluble polyMOFs using a variety of polyligands.