Author(s): Calvin Crawford
Mentor(s): Gabriela Chilom
Institution UTech
Excess heat capacity (CpE) represents the difference between the heat capacity of a mixture and the sum of the heat capacities of its pure components, assuming no interactions. The magnitude and sign of CpE reveal insights into intermolecular interactions within the mixture, such as bonding and structural changes. For CpE to be a reliable metric, measurements need to be rapid, accurate, and sensitive to composition variations. Differential Scanning Calorimetry (DSC) is commonly used to measure heat capacities, but conventional DSC instruments, while precise, are limited by the small sample quantities they can accommodate. This limitation is particularly challenging when analyzing complex, heterogeneous mixtures where component interactions are critical, as deviations from ideal composition can introduce artifacts that mimic or obscure CpE effects. This study introduces a custom-built scanning calorimeter designed to balance high sensitivity with a larger sample capacity, reducing composition-related artifacts and improving the accuracy and reproducibility of CpE measurements. This approach enhances the reliability of excess heat capacity as a tool for characterizing complex mixtures by mitigating the impact of sample heterogeneity.