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Electrochemical and infrared spectroscopy studies of an ionizable self-assembled monolayer

Switchable surfaces, also called smart surfaces or controllable surfaces, respond to changes in their local environment resulting in altered surface properties. There are various environmental perturbations that can cause changes to the surface properties but the focus of this thesis is on the affect of electrostatic potential. Significant evidence is provided from previous reports on electrochemical and infrared spectroscopic experiments suggesting that self-assembled monolayers (SAMs) of 4-mercaptobenzoic acid (4-MBA) undergo protonation-deprotonation by the application of an electric field. However, there are plenty of aspects of this electric field driven protonation-deprotonation mechanisms using carboxylic acid terminated SAMs that are not well understood. Most importantly, there is a lack of model independent measurements to validate this process. As such, experimental techniques utilizing infrared spectroscopy were employed to correlate electrochemical measurements and models.<p>
This body of work demonstrates the importance of the intermolecular hydrogen bonding network on the measured voltammetric peak associated with the protonation-deprotonation of these SAMs. The voltammetric peak height diminishes with increasing exposure to an electrolyte solution. This behaviour is attributed to the replacement of the carboxylic acid protons with electrolyte cations and ultimately the disruption of the hydrogen bonded network.<p>
We attempted to further our ex-situ infrared measurements by using an in-situ spectroelectrochemical technique. We had some initial successes, presented within, but more work is needed to complete this picture and is beyond the scope of this thesis. To summarize, the protonated state of SAMs of 4-MBA can be driven by the application of an electric field providing a potential platform to build a controllable smart surface.

Identiferoai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:SSU.etd-10212009-111400
Date21 October 2009
CreatorsRosendahl, Scott Michael
ContributorsRogers, Michael, Bowles, Richard, Gravel, Michel, Burgess, Ian
PublisherUniversity of Saskatchewan
Source SetsLibrary and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada
LanguageEnglish
Detected LanguageEnglish
Typetext
Formatapplication/pdf
Sourcehttp://library.usask.ca/theses/available/etd-10212009-111400/
Rightsunrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Saskatchewan or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report.

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