PREPARATION AND CHARACTERIZATION OF FLUORESCENT COPOLYMER EMULSION CONTAINING EUROPIUM BY SOAP-FREE EMULSION POLYMERIZATION

A novel fluorescent complex was synthesized with Eu3+, acrylic acid (AA) and 1, 10-phenanthroline (Phen), using absolute ethyl alcohol as solvent. The chemical structure and fluorescent property of the complex were characterized by elemental analysis, FTIR, H-1-NMR spectroscopy and fluorescence spectroscopy. The results indicted that the fluorescent complex Eu(AA)(3) Phen was successfully prepared and had an excellent fluorescence property. Afterwards, a series of novel fluorescent copolymer emulsions were prepared via soap-free emulsion polymerization, with methyl methacrylate (MMA) and acrylamide (AM) as main monomers, Eu(AA)(3) Phen as functional monomer and 4-vinylbenzenesulfonic acid sodium salt (NaSS) as polymerizable emulsifier. The structures of the copolymers were characterized by FTIR. The results revealed that copolymerization occurred among MMA, AM, NaSS and Eu(AA)(3) Phen, and the copolymers were prepared successfully. The influences of the dosages of Eu(AA)(3) Phen on the stability of copolymer emulsions were studied by the technique of centrifugation, indicating that the emulsions had excellent stability. The average particle size and distribution were measured by photon correlation spectroscopy (PCS), and the result showed that the hydrodynamic diameters and distribution of micelles both increased gradually with the contents of Eu(AA)(3) Phen. The morphology of latex particles were examined by transmission electron microscopy (TEM), and the images showed that the particles were sphere-shaped, whose size was in good agreement with the measurement results from PCS. In addition, the emulsions were characterized by fluorescence spectroscopy, and it was found that copolymer emulsions exhibited marked luminescence at the wavelength of 594 and 619 nm. More importantly, the fluorescence intensity increased gradually with the contents of Eu(AA)(3) Phen in the copolymers.