Phase transitions of n-C32H66 measured by means of high resolution and super-sensitive DSC

A high resolution and super-sensitive differential scanning calorimetry (DSC) has been constructed by using two kinds of semi-conducting thermoelectric modules; one is used as a high-sensitive heat flow sensor and the other is for a main heater or cooler using the Peltier effect. The baseline fluctuation of the calorimeter was within ±25 nW. Thermal analysis of n-C32H66 was conducted using this DSC and two large peaks due to the solid-solid transition at 339.1 K from the crystalline phase to the rotator phase and the melting transition at 341.9 K were observed at the heating rate of 0.4 mK s−1. In addition, a small peak was detected first by DSC at 338.1 K, indicating a high sensitivity of this DSC. In the solidifying process from the melting state at the cooling rate of 40 μK s−1, several small exothermic sub-peaks were observed in addition to the main solidifying peak.