Research On Molecular Chain Orientation Characteristics And Optical Anisotropy Of Polymer Materials Based On MOF Nano-confined Space

With the advent of the 5G era,people have increasingly higher requirements for optical communications.With its unique advantages,highly optically anisotropic polymer materials and waveguide devices that process and manipulate the polarization state of light have become one of the key research directions for future development.The optical anisotropy of a material means that all or part of the chemical and physical properties of a substance change with the change of direction,showing different properties in different directions,which is mainly reflected in the dichroism of the material in a macroscopic view,orientation characteristics and birefringence.However,the polymer optical waveguide devices fabricated based on optically anisotropic materials have some shortcomings,such as the inability to accurately control the birefringence and high cost.Therefore,the preparation of a low-cost,high-birefringence polymer material has become the key to the design and preparation of polymer optical waveguide devices in the future.The use of Metal-Organic Frameworks materials can be used as templates for ordered pore structure.The polymer chains are efficiently introduced by the direct chain introduction method,and finally the MOF template is selectively removed to obtain oriented polymer materials.In this paper,through a combination of theoretical design and experimental preparation and characterization,a long-range ordered MOF template material was synthesized and the non-luminescent PMMA polymer chain and the luminescent MEH-PPV polymer chain were efficiently introduced by the direct chain introduction method.Their optical anisotropy and luminescence characteristics are studied.In this paper,a long-range ordered MOF template material is synthesized based on solvothermal method,and the morphology and size of the synthesized MOF are adjusted by adding acidic auxiliary agent and ligand exchange modification.By selecting the appropriate temperature and solvent,the direct chain introduction method is adopted.The efficient introduction of polymer chains,and finally the selective removal of the MOF skeleton to obtain oriented polymer materials.We have fully verified through the results of X-ray diffraction and nitrogen adsorption that the two polymer chains have been successfully introduced into the ordered pores of the MOF.Observing the oriented PMMA obtained under a transmission microscope,we found that the morphology and size of the obtained PMMA are affected by the morphology of the initial selected MOF template and the temperature of introduction.Under the polarized light microscope system,it can be seen that the PMMA obtained after removing the MOF template has a relatively obvious light and dark change,which qualitatively verifies that the obtained product has good optical anisotropy.The measurement results of fluorescence microscopy and photoluminescence spectra show that the MEH-PPV@MOF composite material synthesized by direct chain introduction has better luminescence characteristics.The measurement results of the polarized luminescence spectrum show that the PPV@MOF composite material synthesized by direct chain introduction also has good photoluminescence anisotropy.The research results in this paper provide an effective scheme and experimental guidance for the design and preparation of optically anisotropic polymer materials.