Constructing polymer/metal-organic framework nanohybrids to design compatible polymer-filler-polymer membranes for CO2 separation

Membrane technology is energy-saving and environmentally friendly for gas separation. Mixed matrix membranes containing filler-polymer two components and adjusted transport pathways are promising for carbon capture. However, weak filler-polymer interfacial interaction and filler agglomeration usually cause defect formation and performance deterioration. In this study, we report a concept of polymer-filler-polymer membranes for efficient CO2 separation, highlighted by polymer of intrinsic microporosity (PIM)-metal-organic framework (MOF)-PIM combination. Key point is that the membrane systems consist of polymer matrices, MOFs as fillers for membranes and as hosts for inserted polymers, and polymer guests in MOFs. With partial functionalization of PIM to generate linker-analogous segments and retain unmodified sections, the PIM derivative chains can be uniformly coordinated in MOF nanohybrids and service as interfacial binders to enhance filler-polymer compatibility and filler dispersibility. Meanwhile, the PIM incorporation can regulate the morphologies and inner channels of MOF nanohybrids. For CO2/N2 separation, the polymer-filler-polymer membranes exhibit substantially improved permeability of 9532 Barrer, selectivity of 63.2, and antiaging property. We envisage that this concept reported here provides an alternative route to design compatible and high-performance membranes and other composites for separations and other applications.