Study On The Preparation And Performance Of Metal-Organic Framework Materials Based On Microfluidics

Metal-organic frameworks(MOFs)are a new kind of functional materials with uniform pore size,large specific surface area and diverse structure and function.They have been broadly used in energy storage,catalysis,adsorption separation,fluorescent labeling,biomolecular recognition and other fields.However,the conventional methods for preparing MOFs are still hydrothermal or solvothermal.The limitation of this method is that only one metal-organic framework material can be obtained in a single reaction process.Moreover,most of the reactions need to be carried out under high temperature,high pressure and long-term conditions,which can not achieve continuous and controllable preparation.Therefore,it is very necessary to find a short-term,continuous and controllable method of synthetizing MOFs at room temperature and normal pressure.Self-supporting MOFs are important research topics in the application of MOFs.Compared with the powder MOFs,the macrostructures of self-supporting MOFs,such as fiber,film and gel,give new properties to MOFs.It has shown its unique advantages in the field of drug release,cell labeling,gas separation,energy storage,and supercapacitors.However,the current methods of preparing self-supporting MOFs present the disadvantages of complicated preparation process,expensive equipment and high requirements for preparation technology.Therefore,it is particularly important to explore a method demonstrating simple preparation process,strong operability and low cost to continuously and controllably prepare self-supporting MOFs.Based on the above situation,we propose a simple and general method to continuously and controllably prepared MOFs based on microfluidic technology,and shape them to prepare self-supporting MOFs with well-defined structure,mechanical strength and physical flexibility with retaining their original characteristics.X-ray diffractometer characterization,scanning electron microscope,fluorescence microscope,fluorescence spectrometer,ultraviolet-visible spectrophotometer and other instruments are used to characterize and study the properties of the MOF powders and the shaped MOF functional materials.The main research work is as follows.1.Microfluidic technology is used to design a multi-channel microchip structure.Based on the characteristics of enhanced mass transfer by microfluidics,assisted by temperature control system and stirring system,the rapid preparation of MOFs at atmospheric temperature and pressure is realized.By using the characteristics of microfluidics to continuously control the proportion of reaction raw materials,six kinds of fluorescent MOFs,with a wavelength range of 470 nm-650nm,are continuously,dynamically and controllably prepared.2.A coaxial microreactor is constructed by microfluidic technology.The fluorescent MOF fibers with core-shell structure are prepared by wet spinning and chemical crosslinking.When the flow rate ratio is 1:5-1:9 and the concentration ratio is 1:4-1:7,the fluorescent MOF fibers with high strength and high flexibility can be prepared,which possesses a diameter range of 170?m-410?m,a tensile strength of 85.6 MPa and excellent environmental stability.3.A metal microreactor is constructed by using microfluidic technology.The MOF@polymer precursor is introduced into the microreactor by using MOF@polymer hybrid strategy.The mixed matrix films with different MOF loading are prepared by extrusion through microchannel.The prepared films possess high specific surface area of751 m²g^-1,with uniform thickness,high transmittance,excellent thermal stability and gas adsorption performance.