Preparation And Performance Of Eu³⁺ Complex Luminescent Films Based On Watet-soluble Curdlan

The luminescent films based on the lanthanide composite exhibit high luminescence intensity,long luminescence lifetime,high transparency and excellent processing performance,has great application prospects in the fields of sensors and optoelectronic devices.The thesis aims to use natural polysaccharides as starting materials which have a rich source in nature to develop new lanthanide luminescent films.In this thesis,Curdlan was used as the raw material.Firstly,the water-soluble aminated Curdlan Cur-NH₂ was prepared by azide and reduction.Then,Two kinds of water-solublecurdlanderivatives1-carboxyethyl-3-methylimidazolium bromamidated Curdlan named Cur-NH-IL and Succinic acid amidated Curdlan namedCur-NH-SAwereobtainedbyamidereactionviagrafting1-carboxyethyl-3-methylimidazolium bromide and succinic acid to Cur-NH₂.The synthesized compounds were confirmed by ¹³C-NMR,¹H-NMR,MS and FT-IR.Finally,Cur-NH₂,Cur-NH-IL and Cur-NH-SA were used as polymer matrix to prepare a series of luminescent solutions combination with Eu³⁺?tta?_n@Lap which comes from in situ forming Eu³⁺-?-dikeonate complexes on Laponite platelets in aqueous.Furthermore,the corresponding transparent flexible luminescent films?EuTL@Cur-NH₂,EuTL@Cur-NH-IL and EuTL@Cur-NH-SA?were prepared by casting method.We used the FT-IR,Vis-UV,and FS to test the luminescent films.The transparent luminescent films are colorless under sunlight,and emit red light brightly under the excitation of 350 nm UV light.Moreover,they all have high quantum yield?the minimum is 50.25%,the maximum is 86.87%?,and their fluorescence lifetime shows a significant increase compared with EuTL without water soluble curdlan's derivatives?from 0.139 ms to 0.215 ms?.Moreover,such luminescent films are sensitive to acid/base atmospheres.The red light is significantly weakened until disappears at the HCl vapor;meanwhile,the red light rapidly becomes stronger in the Et₃N gas environment,and the transition is highly sensitive and can be circulated more than 10 times.In summary,the new types of transparent flexible luminescent films of lanthanide complexes were successfully obtained in this thesis.The films showed excellent luminescent performances,and were very sensitive to the acid/base environment.Therefore,they have the innegligible potential application value for developing luminescent sensor.