Abstract: Thiol-functionalized nanosized mesoporous silica particles with a diameter of 50-200 nm were prepared and characterized by TEM, TG, and DTA. (3-mercaptopropyl) trimethoxy silane (MPTMS) was introduced into the silica networks through three synthesis routes. The mercapto group induces significant changes in the particle morphology, transforming highly ordered hexagonal particles into nanoscale bars. The size of mesoporous silica can be adjusted by controlling reacting time. The addition of triethanolamine instead of NaOH leads to the formation of functionalized spherical particles having a diameter of ca 100 nm. The template can be extracted by HCl-ethanol solution for protecting thiol functional group. In addition, the formation mechanism of the mesoporous silica particles was also discussed.

Key words: Mesoporous silica, Thiol-functionalization, Colloidal suspension