Berlin 2008 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 34: POSTERS Polymerphysics
CPP 34.33: Poster
Donnerstag, 28. Februar 2008, 17:00–19:30, Poster A
Nanotomography of semicrystalline polypropylene using bimodal atomic force microscopy — •Christian Dietz1, Mario Zerson1, Christian Riesch1, Alexander M. Gigler2, Robert W. Stark2, Nicolaus Rehse1, and Robert Magerle1 — 1Technische Universität Chemnitz, Reichenhainer Str. 70, 09107 Chemnitz, Germany — 2Center for Nanoscience and Dept. Earth and Environmental Sci., Ludwig-Maximilians-Universität München, Theresienstraße 41/II, 80333 München
High resolution volume images of semicrystalline polypropylene were obtained by stepwise wet-chemical etching followed by atomic force microscopy imaging of the specimen. Compositional contrast changes from crystals that are stiff to the amorphous phase which is rather soft. The dissipated energy as function of the cantilever's oscillation amplitude allows to identify dissipation processes at the nanoscale and to distinguish crystalline from amorphous regions. To enhance resolution a bimodal atomic force microscope was used where the first two flexural eigenmodes of the cantilever are mechanically excited and the cantilever deflection signal is analyzed using two lock-in amplifiers. While the amplitude of the first mode is used as an electronic feedback signal, the amplitude and phase signal of the second eigenmode are used to distinguish compositional changes of the material. This approach allows for a higher signal to noise ratio than the phase signal of the first eigenmode and it is less influenced by the sample topography.