Low voltage scanning electron microscopy and atomic force microscopy: state-of-the-art microscopy techniques for investigations of polymer single crystals

Recent studies on organization and reorganization of polymer single crystals have contributed to the actual discussion on novel approaches towards understanding polymer crystallization and melting. In this context, low voltage scanning electron microscopy (LVSEM) and atomic force microscopy (AFM) demonstrate their importance for the investigation of polymer crystals. Both techniques are able to visualize the morphology of individual single crystals, which have a thickness in the order of 10 to 30 nm and a lateral size of a few micrometers, respectively, without any additional sample treatment such as coating or etching. Main advantage of LVSEM is its large range of observation: LVSEM is suited for fast screening and sample quality evaluation on the millimeter or micrometer level, and at the same time it has the prospect for detection of morphological details with nanometer resolution. The main strength of AFM is twofold: first, its excellent ability for precise quantitative thickness determination of the crystals, and second, using non-contact mode it can act as a non-destructive investigation technique, which allows in situ investigation of dynamic processes during sample treatment. By presenting some results of our studies, e. g., time dependent growth or temperature dependent annealing behavior of individual single crystals, we like to point out the specific advantages of the two techniques for fundamental studies on individual crystals, or ultra-thin polymer layers in general.