The synthesis of a core-shell hybrid composite micro-sphere with controllable homogenous or heterogeneous multi-shell structure by multiple-growth via a combination method

The preparation of controllable multi-shell nano and micro particles has great significance not only for their potential applications but also for fabricating novel composite functional advanced materials. In this paper, MSiO₂, MTiO₂ and SSiO₂ with good monodispersity and no agglomeration among spheres have been synthesized successfully based on Stöber's method. MSiO₂ were characterized as the silica with a worm-like mesopore structure and with uniform pore sizes of about 2.0nm, and about 700m²/g of specific surface area. A core-shell hybrid composite micron-sized spherical particle with multi-shell structures by using the synthesized MSiO₂, MTiO₂ and SSiO₂ with a combination method has been designed and fabricated. The multiple-layers of these spherical particles can be controllably prepared via multiple deposits in an alcohol solution system, and the standard deviations of particle size of each sample are less than 3%. The temperature and the seeds mass effect on the morphologies of MSiO₂/SSiO₂ and MSiO₂/SSiO₂/SSiO₂ via multiple-growth by coating solid silica layers have been investigated. In order to illustrate the sphere with multi-shell structure may have multi-functionalized, the MSiO₂ sphere embedded methylene blue in the pores and coated with solid silica shell was fabricated.