Recent progress of SEM technology enabled us to observe the ordered structure of mesoporous materials.
Direct SEM observation of mesoporous materials can provide detail information on the external and
internal structures, though it often faces charging problems of insulating frameworks and the structural
collapse due to the electron beam irradiation. Low voltage SEM observation has become common both
for top-surface imaging and reducing beam damage. In this work, high-resolution, direct SEM imaging of
mesoporous silica powders and films was carried out under the condition of low voltages to characterize
the surface structure that cannot be evaluated by TEM,XRDandN2 adsorption/desorption measurements.
Wesynthesized SBA-15 powders using different aging temperatures, and observed the differences in surface
structure.Wealso observed the surface structure of dip-coated SBA-16 films prepared with different
template concentrations. The SBA-15 powder, which was aged at a lower temperature, was extremely
beam sensitive, and the SBA-16 films prepared on glass substrates were heavily charging. For the SEM
observation, we used beam deceleration and an improved scanning method to reduce the charging phenomenon
and beam damage. We achieved this using a Hitachi S-4800 or an SU8000 FE-SEM, which
both employ a snorkel type objective lens, a beam deceleration function and newly designed beam scan
settings that combine slow and fast scanning techniques.