Calorimetry is an interdisciplinary technique used to directly measure the enthalpy change or heat flow during physical or chemical processes, providing valuable information on the thermodynamic properties of reactions or materials. With the advancement of microelectromechanical systems technology, chip calorimeters have been developed as a more efficient alternative to traditional calorimeters with lower sample consumption and better sensitivity.

This thesis aims to develop the very first enclosed thin-film chip calorimeter for sub-nL liquid sample analysis. The chip calorimeter adopts a silicon nitride based self-enclosed channel to precisely quantify the sample and facilitates a high-precision measurement under vacuum. This thesis has made several original contributions to the field...[ Read more ]

Calorimetry is an interdisciplinary technique used to directly measure the enthalpy change or heat flow during physical or chemical processes, providing valuable information on the thermodynamic properties of reactions or materials. With the advancement of microelectromechanical systems technology, chip calorimeters have been developed as a more efficient alternative to traditional calorimeters with lower sample consumption and better sensitivity.

This thesis aims to develop the very first enclosed thin-film chip calorimeter for sub-nL liquid sample analysis. The chip calorimeter adopts a silicon nitride based self-enclosed channel to precisely quantify the sample and facilitates a high-precision measurement under vacuum. This thesis has made several original contributions to the field of chip calorimetry. First, DNA melting curve analysis was introduced to chip calorimetry for sensor calibration and temperature uniformity characterization. The calibrated chip was further verified by measuring liquid crystal nematic-isotropic phase transitions, and the activation energy of the phase transition was extracted through a series of temperature scans using the Kissinger method. Second, chip calorimetry is applied for the evaluation of the photothermal transduction efficiency of plasmonic nanoparticles; a task often performed on a cuvette-based platform that is slow and inconvenient. Further, the chip calorimeter has been used to perform the differential scanning calorimetry measurements for lysozyme at various pH, concentrations, and scan rates. The chip can provide excess heat capacity peaks and enthalpy change steps without much alteration induced by the thermal lag at elevated scan rates up to 100 ℃·min–1, which is an order of magnitude faster than many chip counterparts.