Abstract: Uniform hollow nanostructural hollow silica microsphers were produced by the layer-by-layer electrostatic self-assembly technique. The core-shell microspheres were constructed by alternately depositing positive polyelectrolyte PDDAMAC and silica nanoparticles (10nm, 20nm) onto the polystyrene PS microspheres which were used as the colloidal templates, then the templates were decomposed by calcination and hollow mesoporous silica microspheres come into being. TEM show monodispered silica microspheres have spherical void. XRD analyses indicate that crystallization degree of silica is nearly the same after heating treatment, which still maintain an amorphous from. The measurements of N₂ adsorption-desorption isotherms yield the surface area of the hollow spheres assembled of silica with a diameter of 10 or 20nm are 282.71m²·g^-1 and 158.17m²·g^-1, and the average pore diameters of them are 11nm and 15nm respectively. The permeability and sustained release property of hollow silica sphere were also confirmed by the experiments of dye loaded and released.

Key words: layer-by-layer self-assembly, hollow silica microspheres, release