Dresden 2006 – wissenschaftliches Programm

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CPP: Chemische Physik und Polymerphysik

CPP 4: New Experimental Techniques

CPP 4.4: Vortrag

Montag, 27. März 2006, 15:00–15:15, ZEU Lich

Transitions in Nanometer thin films - Investigations by AC-Chip calorimetry — •Heiko Huth, Alexander Minakov, and Christoph Schick — University of Rostock, Institute of Physics, Universitätsplatz 3, 18051 Rostock, Germany

Calorimetry is known as a very powerful tool for the characterization of a wide variety of materials and their transitions. The combination of silicon technology and calorimetry opens up new possibilities in this research area as demonstrated recently (1). Based on a differential AC-calorimeter we show an improved experimental setup combining the advantages of the different methods. The measurements are done at slow scanning or at constant bath temperature. The frequency chosen provides a well defined time scale of the experiment. In several cases, e.g. at glass transition, a direct comparison with results from other dynamic methods like dielectric spectroscopy is possible. Due to the differential setup we achieve a sensitive in the pico Joule per Kelvin range allowing to measure samples below one nanogram and consequently films down to 1 nm thickness (2, 3). Because of the small total heat capacity (addenda + sample) not only a high sensitivity is achieved but AC measurements at relative high frequencies are possible too. The capabilities are demonstrated by different nanometer thin polymeric films.

[1] D. W. Denlinger; E. N. Abarra; K. Allen; P. W. Rooney; M. T. Messer; S. K. Watson; F. Hellman, Rev. Sci. Instrum. 65 (1994) 946

[2] H. Huth, A. Minakov, C. Schick, Netsu Sokutei 32 (2005) 69

[3] Lupascu V., Huth H., Schick C. and W"ubbenhorst M. Thermochim. Acta 432 (2005) 222