Picojoule and Submillisecond Calorimetry with Micromechanical Probes

Y. Nakagawa^{1, 2}, R. Schaefer¹, and H.-J. Guentherodt¹

1) Department of Physics, University of Basel, Klingelbergstr. 82, CH-4056 Basel, Switzerland.
2) Toray Research Center, Inc., 3-3-7 Sonoyama, Otsu 520-8567, Japan.

High-sensitive and fast thermal analysis has been realized by using a microcantilever as a "bimetallic" temperature sensor. The experimental limits of the calorimetry at ambient conditions are pursued. In the analysis of phase transitions of n-alkanes, a heat sensitivity of 500 pJ and a time resolution of 0.5 ms were achieved with a commercial AFM cantilever. Heat transfer via air was found to be a problem in precise quantification of the transition enthalpies. A calibration procedure is proposed to overcome the problem. Thermogravimetry with nanogram sensitivity can be also accomplished with the same instrumentation. Future improvements and potential applications of the calorimetry will be discussed.