Formation of highly ordered mesoporous silica materials adopting lyotropic liquid crystal mesophases

Mesoporous silica materials have been synthesised in strongly acidic media at pH 1.3 using high concentrations of a non- ionic surfactant (Brij 76) as a structure- directing agent. Well- defined ordered mesoporous silicas with hexagonal (H-I), lamellar (L-infinity) and solid phase (S) structure have been prepared at room temperature according to the lyotropic liquid crystalline mesophases of Brij 76. At high temperature (60 degreesC), highly ordered cubic (Ia3d), cubic (Im3m) and 3-d hexagonal (p6(3)/mmc) nanostructured materials have been produced. The synthesised materials were studied by powder X- ray diffraction (XRD), the Brunauer- Emmett-Teller (BET) method for nitrogen adsorption/ desorption isotherms and surface area measurements. Transmission electron microscopy (TEM), XRD and TEM patterns for all materials show well- defined long- range porous architectures. It was found that BET surface area values of the nanostructured materials are reduced upon increasing the temperature of synthesis.