The Electrical Properties of Interfacial Double Layers

Jones, Mark Hedley

The Electrical Properties of Interfacial Double Layers

dc.contributor.advisor	Scott, Jonathan B.
dc.contributor.advisor	Wilson, Marcus T.
dc.contributor.author	Jones, Mark Hedley
dc.date.accessioned	2016-09-01T21:01:43Z
dc.date.available	2016-09-01T21:01:43Z
dc.date.issued	2016
dc.date.updated	2016-07-31T19:24:25Z
dc.description.abstract	When solids and liquids are brought together, interfacial double-layers are likely to form. They are too small to feel or see so their presence goes mostly unnoticed at the macroscopic level. A double layer is essentially a cluster of ions and/or charged molecules which are drawn from the body of a liquid to the surface of a solid. They are responsible for stabilising some of our most important fluids -- blood, milk, paints, and inks. Without the protection of double-layers, these mixtures clump and lose their fluidity. This thesis examines both electricity generation from, and the electrical impedance of, interfacial double layers. Interfacial double-layers represent the underlying theme of this work, which is broken into two parts. In part I, double layers are used as a means of converting fluid-mechanical energy into electrical energy. My application for this is an energy harvester that could power electronic water meters. Domestic water meters are typically installed where electrical connection is not feasible. Harvesting energy at the meter may make electronic metering a feasible long-term solution. My findings show that double layer based energy harvesters are not efficient enough for this application yet. However, recent literature on the subject suggests large gains in efficiency may be possible using more exotic materials. Such gains would allow a compact harvester to generate enough energy to operate an electronic meter with wireless transmitter. Part II models the electrical impedance of electrodes submerged in electrolytes. Double-layers contribute to the electrical impedance between solid-fluid interfaces. This work is important to designers of medical implants. Engineers use solutions of saline to mimic the environment experienced by their implants once implanted. This provides a way to test implant electronics without putting a patient at risk. A way of characterising the interface between electrodes and an electrolyte is to model it mathematically. An electrical model of an electrode-electrolyte interface was recently developed by my supervisor, Jonathan Scott. I use that model to compare electrodes placed in solutions of saline to those placed in a living animal. Measurements of the two show that no one concentration of saline matches the situation inside a live spinal cavity. I then create a low-cost electrolyte test solution that better matches the impedance measured in a living animal's spinal cavity.
dc.format.mimetype	application/pdf
dc.identifier.citation	Jones, M. H. (2016). The Electrical Properties of Interfacial Double Layers (Thesis, Doctor of Philosophy (PhD)). University of Waikato, Hamilton, New Zealand. Retrieved from https://hdl.handle.net/10289/10617	en
dc.identifier.uri	https://hdl.handle.net/10289/10617
dc.language.iso	en
dc.publisher	University of Waikato
dc.rights	All items in Research Commons are provided for private study and research purposes and are protected by copyright with all rights reserved unless otherwise indicated.
dc.subject	Electrode modelling
dc.subject	Interfacial double layers
dc.title	The Electrical Properties of Interfacial Double Layers
dc.type	Thesis
pubs.place-of-publication	Hamilton, New Zealand
thesis.degree.grantor	University of Waikato
thesis.degree.level	Doctoral
thesis.degree.name	Doctor of Philosophy (PhD)