Experimental analysis of lateral thermal inhomogeneity of a specific chip-calorimeter sensor

Abstract

© 2019 Elsevier B.V. Fast scanning calorimetry (FSC) requires reliable temperature measurements and knowledge about the temperature distribution in the chip calorimeter sensor. Analysis of the melting temperature of indium placed at different positions on the sensor and thermo-optical analysis of the isotropization of 4,4′-octyloxy cyanobiphenyl (8OCB) liquid crystal allow estimation of the lateral temperature distribution of chip calorimeter sensors. The chip sensor UFS 1 (Flash DSC1™ Mettler Toledo, Switzerland) was chosen as an example but the procedures described also hold for other sensors. The data revealed on one side existence of distinct hot- and cold-spots and on the other side an area with a rather homogeneous temperature distribution. The latter, central area of the sensor is recommended for placing samples if precise measurement of transition temperatures are anticipated. The observed inhomogeneous temperature distribution over the total sensor area is confirmed by thermo-optical analysis of melting of poly (L-lactic acid) and crystallization of isotactic polypropylene, emphasizing the need for careful sample preparation/positioning in typical fast scanning chip calorimeter analyses.