Smart synthesis of polymers and tailored material development inevitably require likewise characterization skills. Besides many other characterization methods the infrastructure of the MPI-P offers an advanced electron microscopy facility with adequate instrumentation in association with the necessary expertise. Our spectrum comprises the examination of a variety of different samples like organic and inorganic nanoparticles, polymers and soft matter, biological specimens and any combination of these.
The challenges for the electron microscopic characterization arising from the wide spectrum of different research projects within the MPI-P are complex and manifold, concerning adequate sample preparation as well as sophisticated microscopic techniques.
The electron microscopy group provides the complete electron microscopy service comprising the initial planning of the experiment, sample preparation, tailored examination and the final discussion of the results.
Scanning electron microscopy (SEM) is the method of choice for surface sensitive imaging and morphological examination down to a size scale of some nanometers. Using low beam currents in combination with a low acceleration voltage down to some 100 V polymeric samples can be imaged with minimal beam damage and hence morphological alteration. Furthermore, discrimination of the backscatter and secondary electron signals together with energy filtering yields additional image information concerning the local electron density and elemental sample composition.
Transmission electron microscopy (TEM) is used when even smaller structures in the sub-nanometer range need to be imaged as for example multicomponent polymeric nanoparticles. Additionally, the analytic potential of the TEM is versatile. Its analytical spectrum comprises electron diffraction techniques, X-ray fluorescence spectroscopy (EDS), Electron energy loss spectroscopy (EELS) and examination under cryogenic conditions.
Electron diffraction yields information of the crystallography of materials, either inorganic or polymer in conjunction with a high lateral resolution. However, in order to exploit these two advantages for the examination of polymer crystals, their extreme beam sensitivity has to be taken into account. This is done by extreme reduction of the beam current. This beam is scanned over the sample area of interest and supplies local diffraction information together with a lateral image of the sample (low dose nano area parallel beam technique).