THESIS
2023
1 online resource (xxiii, 108 pages) : illustrations (some color)
Abstract
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...[
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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.
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