Synthesis And Characterization Of Fluorescent Polymer Microspheres Containing Rare Earth Complexes

Fluorescent polymer microspheres made up of rare earth organic complexesare interesting materials because of their unique luminescence properties.On one hand,they are organometallic luminescent materials which possess high luminescence efficiency;on the other hand,they also possess the advantages of polymer such as good post-processing ability and mechanical properties.With improving maturity of its preparation techniques and testing methods,functional microspheres have become an important field in scientific research.Polystyrene(PS)has become a common carrier material to prepare these functional microsphere due to its excellent mechanical property and high thermal stability.In our dissertation,organometallic complexes of europium organic complex were designed to synthesize,and then used as the fluorescent molecules to prepare corresponding fluorescent microspheres by in-situ dispersion polymerization and gradual solvent evaporation respectively.The fluorescence properties of organometallic complexes in solvent and microsphere carrier were investigated.Moreover,the effects of chemical compatibility between complexes and styrene monomer on the doping rate into microspheres were also studied.These provide some instructional meanings for further investigation of the preparation and application of fluorescent microspheres.The detailed outlines are elaborated as follows:(1)The high efficient luminescence europium organic complex Eu(DBM)3·2TPPO(DBM:dibenzoylmethane,TPPO:triphenylphosphine oxide)was successfully synthesized and encapsulated into polystyrene(PS)microspheres by in-situ dispersion polymerization and gradual solvent evaporation.(These fluorescent microspheres are monodisperse and spherical in shape with diameter around 2 ?m.),The partial diameter of fluorescent microspheres increased with the increase of monomer and initiator;but its uniformity was reduced.The PS fluorescent with monodisperse and micron grade microspheres was prepared,and the two kinds of methods for preparing PS microspheres were studied in detail.The particle size of PS microspheres increased with the increase of monomer concentration and the amount of initiator.While with the increase of PVP content,the PS microsphere size decreased.Finally,the optimum conditions for the preparation of fluorescent microspheres for the two methods are determined via large number of experiments as follows:?in-situ dispersion polymerization with the following conditions:ethanol was used as a solvent,monomer concentration of 23%,PVP amount of 8%,and AIBN amount of 2%,reaction took place under stirring speed of 180rpm for 24h under 70?.? gradual solvent evaporation method with the following conditions:ethanol and water as solvent,monomer concentration of 14%,PVP amount of 7%,DVB amount of 10%,and AIBN amount of 1%,reaction under stirring speed of 120rpm for 24h under 70?.(2)As the rare earth complexes have some solubility in the solvent,and rare earth complexes may dissociated in the polymerization process so that the rare earth ions were dissolved in the solvent phase,which make rare earth ions decrease in doping efficiency of polymer microspheres.Therefore,copolymerized acrylic acid diphenyl phosphoryl methyl ester(ADPME)was employed to solve this problem.On one hand,ADPME has a strong effect with rare earth ions(coordination bond).On the other hand,the copolymerization of this monomer with styrene is more stably fixed in the polymer phase.The results show that with this method,micron fluorescent microspheres with monodisperse,narrow distribution,high luminous efficiency and long fluorescence lifetime can be obtained.