Electrospinning Construct Of One-Dimensional Functional Nanostructures

Magnetic-photoluminescent nanomaterials have potential applications in drug targeting, fluorescence labeling and fluorescence imaging, etc due to their unique magnetic and photoluminescent bifunctional properties. At present, some investigations on magnetic-photoluminescent bifunctional nanoparticles have been reported, however, the fabrication and the properties research of one-dimensional magnetic-photoluminescent bifunctional nanomaterials are rarely reported in the literature, and has become an imperative and meaningful subject of study. Nano-ZnS and nano-NiO have special optical, electrical and catalytic properties, which have broad application prospects in photocatalytic degradation of organic pollutants. Electrospinning is an efficient way of fabricating one-dimensional nanomaterials. Compared with other techniques, electrospinning possesses a lot of priorities, such as more cost-effective, simpler, more flexible, and the size and morphology of the product are easy to control, etc. In this thesis, the red and green fluorescence magnetic-photoluminescent bifunctional composite nanofibers, bistrand aligned composite nanofibers bundles, and the luminescent nanofibers and magnetic-photoluminescent bifunctional bistrand aligned composite nanofibers bundle with tunable emitting colour of red-yellow-green were fabricated by electrospinning. The magnetic and luminescent properties and their interactions between them were also investigated. Besides, Zn.S nanofibers and NiO nanotubes were prepared via electrospinning, respectively, and their photocatalytic properties were investigated.1. Red fluorescence Fe3O4/Eu(BA)3phen/PVP and green fluorescence Fe3O4/Tb(BA)3pben/PVP magnetic-photoluminescent bifunctional composite nanofibers based on ferroferric oxide nanoparticles, europium complex Eu(BA)3phen or terbium complexes Tb(BA)3phen and PVP were fabricated by single axial electrospinning. The morphology of the fibers, optimum adding concentration of the rare earth comlex and the impact of introducing various amounts of Fe3O4nanoparticles(NPs) on the magnetic and luminescent properties were studied. Results show that the diameters of the two kinds of nanofibers are200-250nm. The Fe3O4/Eu(BA)3phen/PVP composite nanofibers exhibited red emissions of predominant peaks at592nm and616nm of Eu3+under the excitation of274nm ultraviolet light, and the optimum concentration of Eu(BA)3phen to PVP as15%; Fe3O4/Tb(BA)3phen/PVP composite nanofibers exhibited green emissions of predominant peaks at490nm and545nm of Tb3+under the excitation of276nm ultraviolet light, and the optimum concentration of Tb(BA)3phen to PVP is20%. With introducing more Fe3O4nanoparticles into the composite nanofibers,the luminescent intensity of the fibers is greatly decreased while the saturation magnetization is enhanced.2. In order to decrease the absorption of the exciting and emitting light when black-coloured Fe3O4nanoparticles were scattered in the composite nanofibers. Fe3O4/PVP//Eu(BA)3phen/PVP and Fe3O4/PVP//Tb(BA)3phen/PVP magnetic-photoluminescent bifunctional bistrand aligned composite nanofibers bundles were fabricated by employing a homemade parallel axial electrospinning setup with the side by side dual spinnerets for the first time. Fe3O4NPs and rare earth complex were respectively dispersed into the individual strand fiber of the bistrand aligned composite nanofibers bundles, so that the rare earth complex was effectively isolated from Fe3O4NPs, which greatly reduced the effect of Fe3O4NPs on the luminescence of complex. The results indicated that the fluorescence intensity of bistrand aligned composite nanofibers bundles was obviously higher than that of the above composite nanofibers prepared by single axial electrospinning when the two nanostructures have the same saturation magnetization. The luminescent intensity is hardly decreased when more Fe3O4NPs were added. This kind of magnetic-photoluminescent bifunctional bistrand aligned composite nanofibers bundles possesses excellent magnetic properties and higher fluorescence intensity.3. A new kind of color-tunable PVP/[Tb(BA)3phen+Eu(BA)3phen] luminescent composite nanofibers which consisted of europium complex, terbium complex and PVP were prepared by single axial electrospinning for the first time. The emission spectrum analysis of samples showed that the emitting color of the PVP/[Tb(BA)3phen+Eu(BA)3phen] luminescent composite nanofibers can be tuned under the excitation of276nm single-wavelength ultraviolet light by adjusting the ratio of terbium and europium complexes in a wide color range of red-yellow-green.4. For the first time, a new kind of Fe3O4/PVP//[Tb(BA)3phen+Eu(BA)3phen]/PVP magnetic-photoluminescent bifunctional bistrand aligned composite nanofibers bundles with high fluorescence intensity, magnetism-tunable and colour-tuned characteristics were successfully prepared by parallel axial electrospinning. Fe3O4NPs and rare earth complex (Tb(BA)3phen and Eu(BA)3phen) were respectively dispersed into the individual strand fiber of the bistrand aligned composite nanofibers bundles. The fluorescence intensity of the Fe3O4/PVP//[Tb(BA)3phen+Eu(BA)3phen]/PVP bistrand aligned composite nanofibers bundles was obviously higher than that of Fe3O4/[Tb(BA)3phen+Eu(BA)3phen]/PVP composite nanofibers when they have the same saturation magnetization. The magnetism of the bistrand aligned composite nanofibers bundles could be tuned by adding different amounts of Fe3O4nanoparticles. The emitting color of the Fe3O4/PVP//[Tb(BA)3phen+Eu(BA)3phen]/PVP bistrand aligned composite nanofibers bundles can be tuned by adjusting the ratio of europium and terbium complexes in a wide color range of red-yellow-green. Thus, a kind of magnetic and color-tunable bifunctional bistrand aligned composite nanofibers bundles were obtained.5. ZnS nanofibers with the diameters of200±79nm were prepared by the combination of single axial electrospinning with vulcanization technology, and their photocatalytic properties were investigated. The results showed that the photocatalytic degradation rate of ZnS nanofibers on rhodamine B was higher than ZnO nanofibers, and reached up to98.8%after UV illumination for60min.Therefore, the prepared ZnS nanofibers had outstanding photocatalytic property.6. Ni(NO3)2/PVP hollow composite nanofibers were prepared by coaxial electrospinning, and NiO nanotubes with the outside diameters of185nm and inside diameters of40nm were fabricated by calcining the relevant composite nanofibers. The photocatalytic properties were studied. The results showed that the photocatalytic degradation effect of NiO nanotubes on rhodamine B was better than NiO nanofibers.