The Preparation And Properties Of Magnetic Microspheres Of Naphthalimide Fluorescent Polymer

The fluorescent polymer magnetic microspheres have the characteristics of both magnetism and fluorescence.They can migrate and label under the action of magnetic field.There are still some disadvantages in the development of fluorescent magnetic dual-functional microspheres,such as:low yield of fluorescent monomer,low efficiency,low color fastness of fluorescent monomer,easy migration,high toxicity and low compatibility with organism.Therefore,the preparation of polymer composite microspheres with high yield,high color fastness,no migration,superparamagnetism,migration under magnetic field and fluorescent labeling function has always been the goal pursued by researchers.In this paper,the fine emulsion polymerization method,mainly from the following aspects of exploration and research:1.The fluorescent dye monomer FD1/FD2 was synthesized from 4-bromo-1,8-naphthalene anhydride 2-amino-1,3-propanediol,sodium methoxide,diethylamine and acryloyl chloride by three steps of imidization,substitution and esterification,respectively.The fluorescent dyes were characterized by ¹H NMR,FTIR,UV-Vis-UV and fluorescence spectra.The results show that the fluorescence quantum yields of the reactive dye monomer FD1/FD2 are 0.82 and 0.06 respectively.The maximum absorption wavelengths（λmax）of FD1/FD2 in ethyl acetate solutions in UV-Vis absorption spectra are 361 and 413 nm,and the maximum excitation wavelengths（λex）and the maximum emission wavelengths（λem）of FD1 in fluorescence spectra are 362and 431 nm respectively.And the maximum excitation wavelengths（λex）and the maximum emission wavelengths（λem）of FD2 in fluorescence spectra are 430 and 515nm respectively.2.Magnetic Fe₃O₄ nanoparticles were prepared by thermal decomposition from FeCl₃·6 H₂O,sodium oleate,oleic acid and octadecene.It was characterized by X-ray diffraction（XRD）,transmission electron microscopy（TEM）,and particle size analysis.Magnetic Fe₃O₄ nanoparticles with high purity,uniform particle size distribution and surface modified by oleic acid were prepared.3.The magnetic Fe₃O₄ nanoparticles were prepared by microemulsion polymerization with styrene（St）,butyl acrylate（BA）,hexadecane（HD）,sodium dodecyl sulfate（SDS）and ammonium persulfate（APS）as magnetic functional units.Polymer microspheres coated with magnetic Fe₃O₄ nanoparticles were prepared.The particle size was between 50 nm and 200 nm,and the monodispersity was high.4.Fluorescent dye monomer FD1/FD2 was copolymerized onto the surface of magnetic polymer microspheres to prepare fluorescent polymer magnetic nanospheres.The microspheres were characterized by transmission electron microscopy（TEM）,scanning electron microscopy（SEM）,particle size analysis and potential analysis.The fluorescent magnetic polymer nanospheres coated with magnetic Fe₃O₄ nanoparticles and polymerized with fluorescent dye monomers were prepared.