Preparation Of Inorganic Oxide Hollow Microspheres With Composite Coatings Structure

Core-Shell structure material is an attractive topic in material areas due to its special nature different from the core or shell single component. Hollow materials are formed by removal of the core by a solvent or heating. Hollow microspheres have widely potential applications as delivery vehicles for the controlled release of drugs, dyes due to their special hollow structure. The surface of the shell contains a lot of microporous, was permeability. Polystyrene spheres are more used as a template to prepare core-shell materials nowadays. And nano-scale core-shell spheres produced, but for micron-level core-shell spheres relatively few reports.Monodisperse polystyrene microspheres with 3～5μm diameter were synthesized by dispersion polymerization. As sulfonated polystyrene microspheres template, Titania coated polystyrene core-shell spheres produced through hydrolysis Tetrabutyl titanate in ethanol. The influence of Tetrabutyl titanate, deionized water and reaction time on the formation of the core-shell microspheres and hollow microspheres are studied. It revealed that core-shell spheres were smooth and homogeneous surface on the condition of 30mg template, 1.0ml Tetrabutyl titanate and 0.5 ml deionized water. Coating reaction almost finished in 2 hours. The resulting hollow titanium dioxide was obtained by removal of the core with toluene or by calcination. From the individual broken particles fracture observation, a single coating thickness about 50nm.Using chitosan modified PS/TiO₂ core-shell particles as template, silicon dioxide coating formed onto PS/TiO₂ surface by hydrolysis tetraethyl ortho-silicate in ammonia and composite core-shell spheres prepared. Rough and half coating surface in lower ammonia and deionized water concentration. The integrity, uniform and smooth coating surface produced when ammonia and deionized water concentration increased. Hollow microspheres were made by removing template with toluene and calcination.With the same PS/TiO₂ particles as a template, PS/TiO₂/Fe₃O₄/TiO₂ multilayer coated microspheres produced through Fe₃O₄ nanoparticles adsorption and hydrolysis of Tetrabutyl titanate in ethanol. TiO₂/Fe₃O₄/TiO₂ composite sandwich structure hollow particles obtained when removing cores. Ferrous and ferric as raw materials, magnetic coating spheres prepared by chemical coprecipitation method. It revealed that both Fe₃O₄ and Fe(OH)₃ composite coating formed. The more homogeneous and rough surface core-shell microspheres obtained using ferrous as material by precipitation method. Magnet macro tests showed that these microspheres are good magnetic properties.