Determination of morphology and texture, degree of order and orientation of chain molecules requires imaging instrumentation
appropriate for a wide range of length scales. Optical microscopy in reflected and transmitted light along with associated techniques
covers the regions down to roughly 1 µm. In addition, polarization microscopy is a powerful tool providing evidence of mutual o
rientation of macromolecules. The cost of sample preparation for light-optical microscopic observations is modest.
Imaging of morphologies at dimensions down to several Å requires higher microscopic resolution. Their visualization
is the domain of transmission electron microscopy (TEM) which generally requires appropriate preparation necessary to provide very
thin (approx. 50 nm) and thus electron transparent samples.
The electron microscopy group operates 3 TEM“s providing a resolution down to 1.5 Å with a wide range of analysing capabilities.
Equipped with an integrated electron energy loss spectrometer (EELS) the LEO 912 TEM can be applied to differentiate phases containing
distinct heteroatoms. Supplementarily, the Tecnai F20 offers the possibility of scanning TEM (STEM) together with an energy dispersive
x-ray analysis (EDX) and a high angular annular dark field (HAADF) detector. The first supplies local information on the elemental
composition of the sample whereas the latter provides STEM dark field information with an element specific contrast depending on the atomic number.
Furthermore, many scientific questions concern the molecular structure and self-assembly in a liquid surrounding.
These are usually only accessible for methods using scattering techniques since common imaging methods need a dry sample, which might
change the native structure of the objects under examination. However, with special equipment it is possible to vitrify the sample
solution as a thin film and to examine the sample by Cryo-TEM in its native environment.
The investigation of surfaces in a medium resolution range down to some nm is the domain of scanning electron microscopy (SEM).
Imaging using low acceleration voltage (< 1 kV) supersedes any additional coating of the sample for conductivity reasons. Thus,
SEM examination requires plain sample preparation only.
Moreover, the electron microscopy group is an integral part of the Electron microsopic Centere Mainz (EMZM),
which is an integration of electron microscopy groups at the university of Mainz and the MPI-P in order to gain synergetic effects
in sharing expertise and equipment