Preparation And Characterization Of Inorganic / Organic Composite Core / Shell Structure And Shell Material

This work studies about controllable fabrication of SiO₂ andSiO₂/polypyrrole core/shell particles. An improved ethanol hydrolyzationprogress has been used in the synthesis of SiO₂ particles; then an in-situpolymerization route has been developed to synthesize SiO₂/polypyrrolecore/shell particles with controllable shell thickness. Hollow polypyrrolespheres could be obtained via etched method by HF. The influences oftemperature and addition volume of pyrrole monomer on the shapes ofproduct are explored. The morphology, structure and chemicalcomposition of the SiO₂,core/shell particles and hollow spheres areobtained in this study are investigated by SEM, TEM, and FTIR spectrum.The results of TEM and SEM show that PPy has formed a uniform shellround the core. The diameter of hollow sphere is about 400 nm. Thethickness of shell could be adjusted in 40 nm～70 nm by changing thepyrrole monomer's concentration.Using the same fabrication mechanism, we have fabricatedFe₃O₄/PPy core/shell particles. The result of FTIR,magenetic andelectromagnetism implies there is an interaction between Fe₃O₄ and PPy.Fe₃O₄/PPy core/shell particles have a wider microwave absorption bandthan that of Fe₃O₄.A method for the synthesis of metal oxide hollow spheres has beendeveloped by using carbonaceous polysaccharide microspheres preparedfrom saccharide solution as templates. Hollow spheres of a series of metaloxides have been prepared in this way. The method involves the initialabsorption of metal ions from solution into the functional surface layer ofcarbonaceous saccharide microspheres; these are then densified andcross-linked in a subsequent calcination and oxidation procedure to formmetal oxide hollow spheres. TEM has been used to characterize thestructures. The result of the fluorescence spectrum of La₂O₃: Eu hollowspheres show the hollow structure can influence the fluorescenceperformance of La₂O₃: Eu hollow spheres.