In our project we work with planar particles of titanium dioxide (TiO2) as a potential UV absorber for composite construction parts which are on organic base. Particles of TiO2 synthesized the same way were already characterized earlier but with different results of morphology particles than we obtained. We decided to focus on the influence of increasing scale of synthesis and sample preparation for electron microscopy on particles’ morphology.
It is well known that scanning electron microscopy thanks to its long depth of field is suitable tool for acquiring information about the morphology of particles and their surface features. Nevertheless, for a reliable ultrahigh resolution image specific procedures regarding sample preparation must be adopted, and the measurement conditions must be carefully chosen. Usually this part of research is underestimated.
In our case scanning transmission electron microscopy (STEM) and transmission electron microscopy (TEM) was applied as complementary methods towards to SEM. Transmission mode was used to identify and compare the same specimen area with scanning mode otherwise TEM was much more reliable for detailed characterization of particles because of its better resolution. We compared our experimental studies with current state of the art and show also the influence of substrate (carbon tape or silicon wafers) and sample preparation on the obtained images.
Titanium dioxide is a semiconductor therefore in case of observation of non-coated specimen in high vacuum mode one has to deal with the unavoidable charging effect. To reduce the signal‐to‐noise ratio, low energies were used (5 and 10kV) as well as different ways of obtaining the image (photo versus integrated image). Removing possible contaminants (thin hydrocarbon film) from the specimens’ surface by means of ultraviolet radiation revealed to be helpful.