Date of Award
Master of Arts (MA)
Electrical and Computer Engineering
This thesis presents a three dimensional on-chip microfabricated calorimeter (μ-calorimeter) to extract thermal diffusivity and specific heat capacity of liquid samples. These thermal properties are used to understand thermal reaction behavior, obtain information of stability for reactant molecules, and characterize a material. Thermally characterized solvents can be utilized to investigate a solute. The μ-calorimeter introduced in this work has 3D wafer-scale structure. The μ-calorimeter consists of a reaction chamber, a nickel heater, and a resistance temperature detector (RTD) sensor. The reaction chamber enables analysis of 200 nl liquid samples. Also, its enclosed structure prevents liquid sample evaporation during an experiment. The heater and the sensor are integrated on the top and bottom sides of the reaction chamber. The heat flux travels directly through a liquid sample from the heater to the sensor with this configuration. The heat penetration time measurement and thermal wave analysis (TWA) are used to measure thermal diffusivity and specific heat respectively. The heat penetration time measurement is the method that measures the heat penetration time through the liquid sample. Depending on the thermal diffusivity of the liquid sample and the heat flux distance, the heat penetration time alters. Since the geometry of the chamber is known, measuring heat penetration time allows detection of the thermal diffusivity of the liquid sample. The TWA is an AC calorimetry method. When an AC voltage of angular frequency, 2ω, is given to the heater, heat is generated by Joule heating at 2ω frequency. The heat capacitance of the sample can be extracted by measuring this 2ω component from the heater. Based on the experimental work of μ-calorimeter, a new measurement system for thermal analysis is introduced. The new system is available to minimize the distance between heater and sensor and facilitate user friendly operation.