Current Trends in Metal-Organic and Covalent Organic Framework Membrane Materials

Metal-organic frameworks (MOFs) and covalent organic frameworks (COFs) have been thoroughly investigated with regards to applications in gas separation membranes in the past years. More recently, new preparation methods for MOFs and COFs as particles and thin-film membranes, as well as for mixed-matrix membranes (MMMs) have been developed. We will highlight novel processes and highly functional materials: Zeolitic imidazolate frameworks (ZIFs) can be transformed into glasses and we will give an insight into their use for membranes. In addition, liquids with permanent porosity offer solution processability for the manufacture of extremely potent MMMs. Also, MOF materials influenced by external stimuli give new directions for the enhancement of performance by in situ techniques. Presently, COFs with their large pores are useful in quantum sieving applications, and by exploiting the stacking behavior also molecular sieving COF membranes are possible. Similarly, porous polymers can be constructed using MOF templates, which then find use in gas separation membranes.

Automated summary

Metal-organic frameworks (MOFs) and covalent organic frameworks (COFs) have been extensively studied for gas separation membranes in recent years. New preparation methods have been developed for MOFs and COFs, as well as for mixed-matrix membranes (MMMs). Unique processes and materials, such as Zeolitic imidazolate frameworks (ZIFs) transforming into glasses and liquids with permanent porosity for manufacturing potent MMMs, have been highlighted. MOF materials influenced by external stimuli offer new directions for performance enhancement using in situ techniques.