A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Nanotechnology

Thesis (M. Eng.) - Asian Institute of Technology, 2015

In this research, the effect on boiling point of water by adding ZnO and SiO2 nanoparticles was studied. At first, the boiling points of water and water with sugar were standardized, calibrated and analyzed statistically. Varying concentrations of ZnO and SiO2 nanofluids were heated at a constant heating rate until 350 °C hotplate temperature was achieved. Boiling temperature was determined after averaging three experiments using a standard liquid thermometer. Linear regression was accomplished for temperature vs. concentration curves to determine correlation. The slope of heating rate was also measured and analyzed with linear regression to gain insight into heating behavior of the nanofluids. ZnO nanoparticles and SiO2 nanoparticles were characterized by UV-Vis spectroscopy, Dynamic light scattering (DLS) and Scanning electron microscopy (SEM). Addition of greater concentrations of ZnO and SiO2 nanoparticles to the solutions resulted in boiling point depression of the fluids compared to pure water. This is in stark contrast to boiling point enhancement achieved for sugar/water mixtures that conformed to traditional principles defined under colligative properties. One possible cause for boiling point depression is that addition of hydrophilic (good surface wetting) nanoparticulates served to lower the overall heat capacity by providing enhanced heat transfer within the solution. Additionally, by adding perturbations to the highly organized water system (e.g. regular clusters linked with hydrogen bonding), disruptions in the normally strong bonding in water required less energy to cause the solution to boil at lower temperatures.