Preparation Of Organic/Inorganic Nanocomposites Based On Superamolecular Self-Assembly

Organic/inorganic nanocomposites not only overcome some shortcomings that inorganic particles are not easy to be processed and organic polymers always have low strength and poor stability, but also get some better performance after the synergistic effect. The self-assembly technology of supramolecular provides a new way for the preparation of nano-materials. In this paper, we get some new types of Organic/inorganic nanocomposites by the self-assembly technology of supramolecular, and we study their nature in great detail. It provide the basis for their potential application in different fields.In chapter 2, we report a novel way to prepare PPy composites by using silica spheres loaded with [Ag(NH₃)₂]⁺ ions as the supporter. Oxidation polymerization of pyrrole monomer and reduction of [Ag(NH₃)₂]⁺ ions took place on the surface of silica spheres simultaneously and raspberry-like composites were formed in one step. No stabilizers were used in the whole process, which significantly improved the quality of the composites. The catalytic property of raspberry-like composites was investigated by reducing the methylene blue (MB) dye with sodium borohydride (NaBH4) as the reducing agent. With traditional metal nanoparticle catalyst compared, the raspberry-like composites could be easily removed from the reaction solution by centrifugation due to the large size of silica sphere supporters and then can be reused.In chapter 3, we report a promising strategy for the facile synthesis of ultra small nanoparticles functionalized hollow silica nanosphere by using a functional cross-linked organic/inorganic hybrid core, which can be obtained simply through successive spontaneous reactions in water. We take Eu2O3 NPs decorated H-SiO2 (denoted as Eu₂O₃@H-SiO₂) nanospheres as an example to demonstrate this concept. First we successfully synthesized EUBA, When europium bromoacetate (EUBA) and (3-aminopropyl) triethoxysilane (APTES) were mixed in water, two successive spontaneous reactions would occur and formed the cross-linked hybrid cores. Under the right conditions, the cross-linked hybrid cores can be translated into Eu₂O₃@H-SiO₂ nanospheres. It can be perfectly indexed to the face-centered cube (fcc) structure of Eu2O3 phase. We confirmed that high pressure within hollow spheres, which is resulted from thermal decomposition of the hybrid cores, is essential for the formation of fcc structured Eu2O3 NPs. At room temperature, Eu₂O₃@H-SiO₂ nanospheres show paramagnetic property with a typical hysteresis curve for paramagnetic material. The fluorescence spectroscopy and fluorescence microscopic photographs of Eu2O3@H-SiO2 nanospheres confirmed that it is red and the lifetime is 0.116 ms.