[Thesis]. Manchester, UK: The University of Manchester; 2018.
Heat transfer fluids are materials responsible for heat distribution, transfer and
storage. Their significance is undeniable - many technological processes cannot be
carried out without using heat transfer materials (for example due to overheating).
These are usually mixtures of many compounds, for example glycols, silicones or water.
Today's technologies constantly require more efficient, environmentally- and economically-friendly
solutions for heat transfer applications. It is necessary to know the full physicochemical
characteristics to design a new heat transfer fluid (mainly density, heat capacity,
viscosity and thermal conductivity). Nanofluids (mixture of a basefluid and nanoparticles)
were proposed as a solution for many industrial issues due to their enhanced thermophysical
properties (i.e. thermal conductivity) than pure liquids. Moreover, these enhancements
exhibit unusual features which make this group of materials interesting from molecular
and industrial point of view. Ionic liquids, task specific materials with tuneable
properties were repeatedly recommended as heat transfer fluids due to their specific
properties (mainly low vapour pressure, wide liquidus range, or non-flammability)
caused by the ionic structure. A very interesting material can be obtained by mixing
ionic liquids and nanoparticles where specific properties of ionic liquids are preserved,
and thermophysical properties are enhanced due to nanoparticles dispersion.
In this work, we investigated ionic liquid - based nanofluids from the experimental
and theoretical point of view, including imidazolium-, pyrrolidinium- and phosphonium-based
ionic liquids with several different anions, and multiwalled carbon nanotubes, graphite,
boron nitride and mesoporous carbon as nanoparticles, and also in mixtures with water.
As a final result, we assessed the molecular recognition of the thermophysical properties
enhancements in ionanofluids, developed the predictive models for physical properties,
compared all investigated systems to commercial heat transfer fluids.
The project was supported by King Faisal University (Saudi Arabia) through a research
fund from the International Cooperation and Knowledge Exchange Administration department
at KFU. Cytec are thanked for the generous donation of the trihexyl(tetradecyl)phosphonium