Preparation And Characterization Of Sodium Alginate/rare Earth Composite Functional Materials

Alginate is an abundant natural polysaccharide.Combing alginate's biodegradable and biocompatible characteristics with lanthanide's excellent luminescence?high purity,long luminescence lifetime,color tunability?will be one of the novel approaches to prepare environmentally friendly hybrid materials.This new kind of hybrid materials has revealed overwhelming potential value in bio-analysis,fluorescence labels,biosensors etc.In this master thesis,photoluminescent hybrid materials based lanthanide complexes and alginate have been prepared by facile preparation methods.Binary and ternary europium complexes have been doped into alginate by physical doping.The prepared hybrid materials presented characteristic red emission of Eu³⁺.In addition,binary and ternary terbium complexes have been doped into alginate matrix.These hybrid materials displayed characteristic green emission of Tb³⁺.Moreover,a new“green chemistry”preparation method to successfully covalently bond lanthanide complex into alginate matrix has been designed.This preparation approach is thoroughly unlike to conventional way and demonstrated great advantages.At room temperature and normal pressure,luminescent lanthanide complexes have been grafted into alginate by ligand replacement in water or common organic solvents.Alginate acted both as matrix and ligand.Hybrid materials showing luminescence in red region have been prepared through carefully choosing organic ligand?2-Thenoyltrifluoroacetone?and corresponding Eu³⁺ion.The green emission hybrid materials have also been prepared by the same method using Tb³⁺as luminescence center.Different organic ligands,such as 4-Aminobenzoic acid and?-diketone?acetylacetone and 1,1,1-Trifluoro-2,4-pentanedione?both showed excellent“antenna effect”in hybrid materials containing terbium ions.Taking into the different applications background of the hybrid materials,four kinds of gel materials?hydrogel,alcogel,xerogel and aerogel?have been prepared.The luminescence of hybrid materials has been characterized by photoluminescence spectra.The study will not only offer a novel way to the preparation of luminescent hybrid materials containing covalently-bonded lanthanide complex,but also enrich the lanthanide hybrid materials and enhance their potential application scope.