Rapid synthesis and morphological control of self-assembly mesoporous silica materials

Mesoporous silica MCM-41 with regular particle morphologies, e.g. gyroids and hexagonal prisms, are rapidly synthesized under strongly acidic condition in less than an hour. All samples show typical XRD patterns and nitrogen adsorption-desorption characteristics of mesoporous materials. It was shown that the gyroids could form in the early stage of reaction during stirring, whereas hexagonal prisms could be obtained by aging the reaction mixtures under static condition at elevated temperature. It was believed that the formation of gyroids was due to the growth of spiral surfactant-silicate micellae in shear stress field during stirring in solution, while the packing habit of hexagonal liquid-crystal structures led to the formation of precise hexagonal prism forms through the accretion of surfactant micellae combined with silicate oligomers after withdrawing the shear stress field.