Residual strain in thermally annealed periodic mesoporous silica revealed by x-ray scattering

We have applied x-ray scattering to characterize residual strain in nanostructured glasses. The first sharp diffraction peak (FSDP) and the nanostructures of periodic mesoporous silica were investigated as a function of annealing temperature. It is found that position and width of the FSDP exhibit different temperature dependencies, which correspond to two types of residual strain caused by defects and constrained nanostructures, respectively. The latter appear to be inherent to the periodic mesoporous material as confirmed by the small-angle x-ray scattering analysis. Our study has implications for the structural properties of periodic mesoporous materials.