Regensburg 2007 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 13: Polymer Physics IV: Thin Films
CPP 13.2: Vortrag
Dienstag, 27. März 2007, 14:45–15:00, H40
Reversible charge storage and modification of thin polymer films investigated by electrostatic force microscopy — •Andreas Kleiner1, Othmar Marti1, Armin Knoll2, Bernd Gotsmann2, and Urs Dürig2 — 1Institute of Experimental Physics, Ulm University, 89069 Ulm, Germany — 2IBM Research GmbH, Zurich Research Laboratory, 8803 Rüschlikon, Switzerland
Atomic force microscope (AFM) modes like force curve measurements, Pulsed Force Mode or intermittent contact techniques apply certain amounts of normal and lateral forces to the sample. In most cases this creates surface charges, similar to the macroscopic contact electrification of insulators. These charges can be imaged by Kelvin Probe or Electric Force Microscopy (KPFM / EFM). The quantity of charge depends on parameters like contact time, applied force or scanning velocity. By adjusting the tip voltage during contact, the amount and polarity can be controlled and charges can be erased and overwritten without change in the polymer structure. High voltages between tip and sample lead to raised topographic features due to the large non-uniform electric field. The height of these structures reaches several nanometers, depending on tip shape and applied voltage, and is reversible. Long-term measurements of these surface charges on different polymers at various temperatures will lead to a better understanding of charge storage and transport mechanisms on thin films.