The synthesis of micron-sized spherical core-shell particles with a thin mesoporous silica shell is shown in this work.The dense silica used as the core is prepared by calcination of a mesoporous SBA-3-type silica,in the form of micron-sized spherical particles.The shell is formed by polycondensation,upon the core particles of: a) tetraethylortosilicate in the presence of a triblock copolymer Pluronic (P123 or F127) in acidic medium (CSA samples) or b) Silicic species,which are generated by partial dissolution of the core in basic medium (NH_4OH) in the presence of cetyltrimethylammonium bromide (CSB samples).Conditions that improve the interaction between the nuclei and the shell precursors in order to form mesoporous shells are discussed.The results of the evaluation of some of these samples as stationary phases in normal HPLC show the interest of these materials for this application.
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