Regensburg 2010 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 11: Poster: New Instruments and Methods

CPP 11.11: Poster

Montag, 22. März 2010, 16:30–18:00, Poster C

Local thermomechanical characterization of phase transitions on polymers using heated SFM-probes — •Thomas Fischinger, Martin Laher, and Sabine Hild — Department of Polymer Science, Johannes Kepler University Linz, Altenbergerstrasse 69, 4040 Linz, Austria

Thermal analysis methods are important instruments for polymeric research, however, up to now mainly bulk properties are detected. Local thermal analysis (LTA) based on scanning probe microscopy (SPM) allows the probing of melting and glass transition temperatures on a 100 nm length scale. To understand local mechanisms for temperature-induced phase transitions in polymers quantitative measurements of characteristic thermomechanical properties such as glass transition and melting temperatures as well as temperature dependent elastic and loss modulus and thermal expansion coefficients in nanoscale volumes are required. Since conventional LTA is insensitive to changes in the dissipative properties in the materials a new approach based on the combination of acoustic atomic force microscopy band excitation detection and a heated tip probe is for the unambiguous detection of changes in resonance frequency and tip-surface dissipation. In the first step, an appropriate temperature calibration method has been established using carboxylic acids with defined melting points to correlate the deflection signal or amplitude and frequency changes with the temperature of the probe. Bases on this, the glass transition temperature will be determined on microscopic scale. The opportunities given by this method are demonstrated in selected model polymeric systems.