An investigation of the thermodynamic properties of molecular crystals by the differential scanning calorimetry

The thermodynamic properties of long-chain molecular crystals (LMC) have been investigated by using differential scanning calorimetry. The impact of the chain length and of the chain end group type on the thermodynamic characteristics of the first and second order phase transitions in LMC has been studied. A method of the analysis of the peak shape of the first order transitions based on the theory of diffused phase transitions has been developed. The method allows one to estimate the size of the new phase nuclei within the bulk of the former phase. To estimate a true peak shape of the first order phase transition, a method to separate the overlapped heat capacity peaks has been proposed for the first time. This new method takes into consideration the hysteresis effects.