Study On The Spectral And Other Properties Of Poly(N-isopropylacrylamide) Containing Rare Earth Ions (Tb, Eu)

As a kind of temperature-sensitive material, the application of Poly (N-isopropylacrylamide) (PNIPAM) nanoparticle has been paid much attention in recent years. In order to obtain multi-sensitive hydrogels, many studies were focused on theoretic explanation of the stimuli-response mechanism and the copolymerization of NIPAM with other monomers to modify their properties,which can be used for developing the new applications in the biomedical and fluorescence field.Based on the synthesis of PNIPAM and PNIPAM-g-P(NIPAM-co-St) (PNNS) by free radical and two-stage emulsifier-free emulsion polymerization, a new kind of the complex of rare earth ions (Terbium, Europium) and PNNS and PNIPAM with the novel temperature-responsive, magnetic and fluorescence properties was successfully prepared and characterized with different techniques. The main results obtained are as follows:1. Effects of initiator dosage, stirring rate, phase ratio and polymerization time on the PNNS core-shell nanoparticle sizes and monodispersity were investigated systematically. Then, nanoparticle was prepared under optimum conditions.2. The research interest of this thesis is concentrated on temperature-responsive, magnetic and fluorescence properties of complexes, and the research work were carried out by scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet-visual (UV-vis) absorption spectroscopy, X-ray photoelectron spectroscopy (XPS), SQUID magnetometer, dynamic light scattering (DLS) and fluorescence spectroscopy.3. Effects of reaction condition and composite of complexes on spectra properties were investigated by fluorescence spectrum. The concept of negative cooperative effect of the second ligand of PNIPAM-Tb(â…¢)-Phen was put forward, which accounted for why the introduction of Phen reduced the fluorescence intensity of ternary complexes of PNIPAM-Tb(â…¢)-Phen. Especially, PNIPAM-Eu(â…¢)-TTA, PNNS-Eu(â…¢)-TTA and PNNS-Tb(â…¢)-Phen not only possess intensive characteristic fluorescence, but also exhibit stable chemical behavior.