Study On Preparation Of P(NVA-co-St) Copolymer Nanospheres And Interaction With Rare Earth Ions

In this paper, N-vinylacetamide (NVA) was selected as a functional monomer, the random copolymer P(NVA-co-St) nanospheres and PNVA-co-PSt nanospheres with core-shell structure were prepared by traditional emulsifier-free emulsion polymerization of styrene (St) with NVA and two step emulsion copolymerization respectively. Then, four kinds of binary complexes were obtained by the coordination reaction of P(NVA-co-St) nanospheres or PNVA-co-PSt nanospheres and lanthanide ions such as Terbium(â…¢) and Europium(â…¢).First, for the random copolymer P(NVA-co-St) nanospheres, the reaction conditions such as monomer ratio of NVA to St, amount of potassium persulfate (KPS), polymerization temperature and polymerization time are considered, aim to find out the relationship of these parameters and the diameter of random copolymer P(NVA-co-St) nanospheres. Secondly, the molecular weight of the nanosphere sample was determined by Gel permeation chromatography (GPC). The complexes of P(NVA-co-St) nanospheres or PNVA-co-PSt nanospheres containing rare earth ions were characterized by Transmission electron microscopy (TEM), Scanning electron microscopy (SEM), Zeta potential, Fourier transform infrared spectroscopy (FTIR), Ultraviolet spectroscopy (UV) and Fluorescence spectroscopy.The experimental results of TEM and SEM showed that resulting nanospheres with nice sphere structure and narrow distribution in diameter, and its diameter has not been obviously changed after the rare earth ions adding into copolymer nanospheres. The results from Zeta potential, UV and FTIR spectra demonstrated two interactions between the copolymer nanospheres and rare earth ions, which one is electrostatic force, and another is coordination action. The two forces maybe change the conformation and conjugated structure of these nanosphere ligands, eventually leading to the changes of their spectral properties.The fluorescence emission spectra show that the complexes prepared by PNVA-co-PSt nanospheres with core-shell structures were better than the random copolymer P(NVA-co-St) nanospheres for fluorescence intensity. The binary complex of PNVA-co-PSt nanospheres containing Tb(â…¢) has a very high color purity for its sensitivity emission peaks, but the emission spectra of the complex containing Eu(â…¢) shows a broad peak, which illuminates that its application maybe restricted.