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

Abstract

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.