| Summary: | 博士 === 國立成功大學 === 化學工程學系碩博士班 === 93 === A simple synthetic route for the preparation of luminescent and magnetic nanocomposite materials is disclosed. The method comprises providing chelating group-containing polymer templates, and producing nanoparticles on the surface of said polymer template. Various kinds of nanoparticles can be synthesized on polymer templates with electroless plating, ultraviolet irradiation, gas phase and liquid phase chemical precipitation methods. This approach is suitable not only for the preparation of semiconductor nanoparticles but also other nanoparticles, especially those that can be prepared from the reduction of an appropriate metal ion-polymer complex.
The PSG-I latex was prepared by the soap-free emulsion copolymerization of styrene and GMA-IDA. The PSG-I microsphere templates were be used to chelating metal ions, at which CdS particles were grown. The growth kinetic of CdS nanoparticles was studied by TEM and photoluminescence spectra (PL). The size and morphology of CdS particles were influenced by the amount of iminodiacetic acid group on the surface of the copolymer microspheres, the pH value, and the chelating amount of Cd+2 ions. The PSG-I1(A)-CdS sample with [Cd+2]/[GMA-IDA]=1/6, pH=3.5, which can prepared the ultrafine CdS nanoparticles with mean diameters of below 5nm immobilized on the surface of copolymer microspheres, emitted photons with a maximum photoluminescence quantum yield (7.4%) than other samples in this investigation. Other microsphere templates, such as poly(St-co-AA)、poly(St-co-MAA)、poly(St-co-AN)、poly(St-co-AAm) and poly(MA-co-GMA-IDA) were also be prepared for synthesizing nanocomposites and compared the luminescence properties with PSGG-I-CdS in this study.
The polymer templates PBGG-I films were prepared by soap-free emulsion copolymerization of BA, GMA and GMA-IDA. GMA-IDA chelating groups within the copolymer were the coordination sites for chelating Cd+2, at which nanosized CdS nanocrystals were grown by the dry method (H2S) and the wet method (Na2S). The particle size and morphology of CdS nanocrystals were observed by TEM, SEM and AFM. TEM observations demonstrate that the mean diameters of CdS nanoparticles can be prepared between 1~3nm inside the matrix of PBGG-I films by the dry method and between 3~6nm by the wet method. AFM images reveal that CdS nanocrystals on the surfaces of PBGG-I films formed by the dry method have rod-like morphology. Both the PBGG-I-CdS prepared by gas and liquid method appears a good luminescent property and the luminescent property can be promoted by dopping Zn+2 ions. In addition, the magnetism material, PBGG-I-Ni, also be synthesized with the particle sizes of nickel are 1~6nm and 20~100nm. The hysteresis curves measured by SQUID reveal that particle sizes in 1~6nm have superparamagnetism phenomenon and 20~100nm have high coercive force and saturated magnetization.
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