In Situ Preparation And Fluorescence Properties Of Coordination Polymer@Cellulose Fibers Hybrid Material

Coordination polymers(CPs)and perovskite with fluorescence properties are widely used in chemical sensing,fluorescence imaging.fluorescence detection fluorescence anticounterfeiting,electronic devices and other fields.Cellulose has many kinds and is easy to be modified.It is an excellent flexible substrate material.With the improvement of the requirements for environmental protection and sustainability of materials,the research on cellulose-based fluorescent materials has gradually developed,and the development of different types of cellulose-based fluorescent materials with different functions has broad prospects.In this paper,taking cellulose fiber as the substrate,CPs were loaded on the surface of cellulose fiber by in-situ synthesis,which was conducive to improve the deposition rate of CPs and the uniformity of CPs distribution.Given that cellulose fibers are not resistant to high temperatures and do not disperse easily in organic solvents,CPs synthesized at lower temperature.in water or water alcohol phase were taken as the main research object to prepare CPs@cellulose fibers hybrid materials with fluorescence anti-counterfeiting or fluorescence detection performance.The main work of this paper was divided into the following parts:(1)Firstly,Pb-MOF@PFs was prepared using pulp fiber as the substrate,and MAPbBr3@Pb-MOF@PFs was prepared using Pb-MOF@PFs as the template in order to further endow the material with fluorescence properties.By analyzing the experimental results.it was found that the deposition amount of Pb-MOF on cellulose fibers surface was affected by different ligands,systems,drug addition sequence and adsorption time.The morphology and composition of Pb-H3BTC(H3BTC as ligand)and Pb-H4BTC(H4BTC as ligand)were different owing to different binding modes between ions and ligands.The lead source can react with MABr to form MAPbBr3,so Pb-H3BTC@CFs and Pb-H4BTC@CFs could be applied to anti-counterfeiting encryption writing paper.MABr was used as the anti-counterfeiting ink to write the content on Pb-H3BTC@CFs and Pb-H4BTC@CFs,and the green fluorescent writing was visible under UV excitation(Ex 365 nm)and achieveing extinction and reconstruction of fluorescence.In addition.Pb-H3BTC@CFs and Pb-H4BTC@CFs were be immersed in MABr solution to prepare MAPbBr3@Pb-H3BTC@CFs and MAPbBr3@Pb-H4BTC@CFs fluorescent anti-counterfeiting paper with green fluorescence characteristics.(2)In order to solve the problem of single fluorescence of perovskite,paper matrix composites with encryption writing performance and double fluorescence anti-counterfeiting were prepared by virtue of the difference of fluorescence excitation wavelength between EuMOF and Tb-MOF and MAPbBr3 to achieve multilevel anti-counterfeiting.Tb-MOF@CFs and Eu-MOF@CFs have a single green or red fluorescence.On this basis,appropriate amount of lead was added to prepare Pb/Tb-MOF@CFs and Pb/Eu-MOF@CFs.MABr was used as the ink to realize encryption writing on Pb/Tb-MOF@CFs and Pb/Eu-MOF@CFs,and the handwriting was MAPbBr3 perovskite.Pb/Tb-MOF@CFs and Pb/Eu-MOF@CFs were immersed in MABr solution to prepare fluorescent anti-counterfeiting paper with two luminescence modes at 254 nm and 365 nm UV excitation wavelengths.(3)The fluorescence of Eu-MOF could not only be reflected in anti-counterfeiting paper,but also could be used for fluorescence detection.However,pulp fibers were not conducive to the sensitivity of Eu-MOF.Therefore,carboxylated nanocellulose fibers(TOCNF)were selected as the substrate to prepare copper ion detection film with fluorescence quenching effect through in-situ synthesis(Eu-MOF@TOCNF).Eu-MOF@TOCNF had good selectivity and high sensitivity and recognition to copper ions in solution when there was interference from other ions.The fluorescence intensity of Eu-MOF@TOCNF decreased gradually with the increase of copper ion concentration,and I0/I-1 showed a good linear relationship with c(Cu2+).One of the most important points was that Eu-MOF@TOCNF not only had excellent chemical stability in acidic or alkaline aqueous solutions with a pH range of 3-11,but also had excellent transparency and mechanical strength,which had a great application prospect in the rapid detection of copper ion specificity.(4)Ciprofloxacin(CIP)is one of many water pollutants.In order to expand the detection object of nanocellulose composite film and solve the problem that Eu-MOF@TOCNF cannot detect CIP,TOCNF were used as the substrate to prepare the new fluorescence-enhanced TbAMP@TOCNF composite film by in-situ synthesis in HEPEs aqueous solution.The large number of carboxyl groups on the surface of TOCNF could be used as an anchor site for metal ions and capture a large number of Tb-AMP.which was beneficial to reducing agglomeration of Tb-AMP.With the increased of CIP concentration,the fluorescence intensity(Ex 254 nm)of Tb-AMP@TOCNF composite films increased,and there was a good linear relationship between I and c(CIP).Tb-AMP@TOCNF had good selectivity,sensitivity and recognition ability to CIP even if it was interfered by other ions and biological small molecules during the detection process.Tb-AMP@TOCNF remained chemically stable under neutral conditions which were similar to the pH environment in human body.So Tb-AMP@TOCNF had potential applications in the detection of antibiotics in urine and blood.(5)In addition to lanthanide coordination polymers with luminescence properties,some coordination polymers can also emit light with the aid of guest.On the basis of the aggregation induced luminescence properties of antibiotics,Zn-BDC@TOCNF were prepared to explore its potential in antibiotic fluorescence detection.It was found that Zn-BDC@TOCNF had no fluorescence propert.When Zn-BDC@TOCNF adsorbed low concentration of tetracycline or ciprofloxacin(CIP)solution,it emitted yellow green fluorescence(365 nm Ex)or blue fluorescence(365 nm Ex)respectively under UV excitation.Taking CIP as an example,there was a linear relationship between fluorescence intensity and concentration of CIP,and the weak acid environment was favorable for its luminescence.Even if CIP was interfered by other ions and biomolecules in the detection process,CIP could still be aggregated to emit light.When the deposition amount of Zn-BDC was less,it did not affect the transparency of the film,whose transparency was about 90%being similar to that of pure TOCNF.The transparency decreased with the increased of deposition amount,but the maximum stress and thermal stability increased with the increase of deposition amount.