In situ SAXS/XRD on mesoscopically ordered surfactant-silica mesophases; What can we learn?

In situ investigations have proven to be a very useful means of understanding the different processes involved in the formation of mesoporous materials. In this communication, we demonstrate the potential of in situ small angle x-ray scattering, SAXS and x-ray diffraction, XRD, measurements for giving both qualitative and quantitative results on the structural evolution during the early stages of the surfactant-silicate composite formation. The examples given are based on results obtained for 2D hexagonal structures, synthesized both under acidic and alkaline conditions. Careful analysis of both the scattering and diffraction patterns allows the different stages of the formation to be described in some detail. Thus, new synthesis approaches can be foreseen that allow the structure of the final hybrid mesophase to be rationally controlled.