Preparation And Properties Of Flexible Nanofibers With Lanthanide Complexes

Rare earth complexes have been widely used in biological imaging,acid-base sensing,pollutant detection,information storage and optical display devices in recent years due to their special optical properties of rare earth elements and the adjustable frame structure of organic ligands.But as a result of pure rare earth complexes’mechanical processing performance is poor,their practical application has certain limitations,so many researchers have focused on combining the rare earth complexes and other materials by different means,so as to improve the machining performance of composite materials,and further promote their applications in real life.In this paper,two kinds of pyridine derivatives as ligands were used to synthesize fourteen complexes with rare earth metal ions,and three kinds of complexes with excellent luminescent properties were combined with polymer matrix by electrospinning technology to form composite nanofiber films with excellent performance.The content of this paper mainly includes the following three chapters:In chapter 1,the research background of rare earth complexes and electrospinning technology is briefly described,and the research progress of rare earth compounds composites in recent years is summarized.In chapter 2,4-carboxyphenyl-2,2’:6’,2’’-tridipyridine and twoβ-diketone were used as the ligands,ten rare earth complexes were successfully synthesized by solvent volatilization at room temperature.The crystal structures,FT-IR,PXRD,fluorescence properties and thermal stability of these complexes were investigated.Based on the properties of 1-Eu,which has good red light emission and long fluorescence lifetime,the detection properties of 1-Eu for Fe³⁺in aqueous solution and nitrobenzene were discussed.It was found that1-Eu has high sensitivity and selectivity for both of them,and the response time of detection is very short.1-Eu was combined with polyacrylonitrile and polymethyl methacrylate substrates by means of electrospinning to prepare composite fluorescence nanofiber membrane.Through the infrared spectrum analysis and X-ray powder diffraction,fluorescence spectroscopy,fluorescence decay curve and thermogravimetric,the fluorescent fibers are characterized in detail and the influence of different matrix on composite materials is analysed.In the third chapter,the crystal structure,FT-IR,PXRD,fluorescence properties and thermal stability of the four rare earth complexes with 5-sulfoisophthalic acid and phen as the ligands were investigated.Based on the properties of the complex 12-Tb,which has good green light emitting,long fluorescence lifetime and high quantum yield,the detection properties of 12-Tb for Fe³⁺and nitrobenzene were discussed.It was found that 12-Tb had high sensitivity and selectivity for both,and the response speed of detection was very fast.The complex 11-Eu and 12-Tb were physically doped with polyvinylpyrrolidone and polymethyl methacrylate matrix,respectively.And the composite fluorescent nanofiber films with high fluorescence intensity,long fluorescence life,good thermal stability and mechanical properties were prepared by electrospinning.Considering that 11-Eu and 12-Tb are isomorphic complexes,and both of them have excellent luminescent monochromatism.Therefore,we mixed the two with PMMA matrix to form composite polychromatic luminescent nanofibers.The resulting composite nanofibers can adjust the luminescence color by adjusting the doping ratio of 11-Eu and 12-Tb,and the series of films can show tunable luminescence from green to yellow to red under the irradiation of 254 nm ultraviolet light.