Preparation of MMMs
After successful synthesis of MOF materials, the MOF NPs and pMOF MSs were mixed in PSF matrixes to fabricate MMMs. The MOF particles and PSF powders were first dispersed and blended in CHCl3 for obtaining homogeneous inks, followed by casting and complete drying for membrane formation. The SEM images of the pristine PSF membrane, MOF-NP/PSF MMM (NH2-UiO-66 NPs and PSF), and pMOF-MS/PSF MMM (polymer-embedded NH2-UiO-66 MSs and PSF) were captured for observing the microstructures (Figure 4 and Figure S5,S6). Compared with the smooth PSF membrane, the MOF-NP/PSF and pMOF-MS/PSF MMMs displayed rough cross section due to the incorporation of MOF fillers. It could be found that the serious aggregation of fillers and the distinct interfacial defect between two phases appeared in the MOF-NP/PSF MMM (Figure 4a,b), which would serve as non-selective pathways for molecular transports and then reduce selectivity. The filler aggregation and the interfacial defect of the pMOF-MS/PSF MMM were alleviated substantially, derived from the identical characteristics of the embedded PSF with the matrix of MMMs as well as the micrometer-sized structures of the pMOF MSs (Figure 4c,d). The broken pMOF MSs and the well cohesive interface suggested that the interfacial binding force was even stronger than that of the intrinsic MSs themselves (Figure 4d). The tight interfacial combination confirmed the excellent affinity of the polymeric matrixes to the pMOF MSs.