Preparation And Interfacial Compatibility Of MOFs/Polymer Composite Membrane Materials

Metal-organic frameworks(MOFs)with the advantages of large specific surface area,good stability,tunable channel structure and easily controlling were potentially applied in areas such as catalysis,separation,biological medicine,sensing.Although MOFs is becoming a hot research topic in the field of organic-inorganic hybrid materials,they are usually loose powders or crystal particles,limiting their engineering operation and processing.This study chooses the good processable performance of polymer materials combing with stable MOFs(ZIF-8 and UiO-66,HKUST-1)to form the composite membrane materials.It is expected that,the pore structure characteristics of MOFs can be retained with the good physical,thermal and mechanical stability.We investigated the interfacial compatibility between different MOFs and polymer materials to provide theoretical basis for the preparation and application of MOFs/polymer composites.The effects of method,solvent type and MOFs loading capacity on the structure and performance of MOFs/polyethersulfone(PES)composite membrane materials were investigated,the optimized process for preparation of composite membrane materials were obtained.Three kinds of MOFs/PES composite membrane materials with good quality were successfully prepared.By comparing the morphology and porosity of the composite membrane materials,it was found that the solvent exchange method based on DMF as the solvent could produce dense and continuous composite membrane layer with the loading of ZIF-8 higher than 60 wt.%,and the composite has a good gas adsorption performance.The interface structures of three kinds of MOFs/PES were studied by molecular dynamics simulation(MD)calculations.It was found that the ZIF-8/PES composite membrane material has good interface compatibility,which can be attributed to the large overlap interface area,the high atomic coverage,the large number of hydrogen bond sites on the MOFs surface,and the strong interpolymer interaction.Through changing the types of MOFs and polymer materials at the same time,more types of the MOFs/polymer composite membrane materials were prepared.The results showed that ZIF-8 had good compatibility with various of polymer materials(PES,PMMA,PVDF).The dense,continuous composite membranes materials could be formed,and the porosity of ZIF-8 was retained in composite membranes materials.The results of this paper are expected to promote the research on more MOFs combining with different polymers to form the composite materials with specificied properties.