Controlling particle morphology and size in the synthesis of mesoporous SBA-15 materials.

Plate-like particles of SBA-15 form from smaller units (primary particles) that aggregate in an oriented manner. In this report we influence this aggregation by adding salt to the ongoing synthesis, generating well-ordered hexagonal p6m structure (SBA-15), with varying particle diameters. The additions, with either NaCl or NaI, were made at a time corresponding to the onset of oriented aggregation.

Morphology of SBA-15-directed by association processes and surface energies.

We present a model that explains the morphology of mesoporous SBA-15 particles based on the relative surface energies of the defining faces. We also describe how the formation process influences the morphology and hence the surface energies. The model is compared to experimental observations, made primarily with scanning and transmission electron microscopy.

In situ observation of the genesis of mesoporous silica SBA-15: dynamics on length scales from 1 nm to 1 microm.

We report on the mechanism of growth of mesoporous silica (SBA-15, plane group p6m). In situ studies of the formation using ultrasmall angle X-ray scattering (USAXS) and small-angle X-ray scattering (SAXS) covering length scales from 5 to 10,000 A, complemented with UV-vis and transmission electron microscopy (TEM), provide unique data on particle growth coupled with information regarding the progression of the mesostructure formation and the micellar evolution.