Berlin 2012 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 15: Poster: New Instruments and Methods

CPP 15.12: Poster

Tuesday, March 27, 2012, 18:15–20:15, Poster A

Applicability of local thermal analysis using heatable AFM probes with respect to environmental influences for monitoring polymer surface properties — •Martin Laher, Thomas Fischinger, and Sabine Hild — Institut für Polymerwisschaften, Johannes Kepler Universität Linz

Local thermal analysis (LTA) in the nanometer scale has nowadays become a commercial add-on for atomic force microscopes. Heatable cantilever probes with tip radii below 50 nm provide the possibility to perform LTA measurements at defined surface positions with nanometer resolution. On condition that an appropriate tip-temperature calibration has been conducted, phase transition temperatures can be measured. Modification processes like solvent treatment or plasma activation are proposed to change thermo-mechanical properties. In this study, LTA is used to investigated the influence of activation parameters like plasma power or treatment time in softening temperatures on a close to surface region. It has been shown that for time dependent effects like solvent evaporation from swollen polymer surface layers there is an influence of one LTA measurement on subsequent ones. Point arrays of measurements show a thermal influence of each LTA on the surrounding area of several microns which decreases resolution. Supplying additional thermal energy to the sample with an external heater reveals that LTA does not probe softening temperatures but rather the amount of thermal energy transferred. Force distance measurements of mechanical properties are compared to thermal LTA results.