Waveguide Sensor Platforms: A) Development of the Electroactive Fiber-Optic Chip and B) Attenuated Total Reflectance Spectroscopy of New Molecular Materials

Persistent Link:
http://hdl.handle.net/10150/194142
Title:
Waveguide Sensor Platforms: A) Development of the Electroactive Fiber-Optic Chip and B) Attenuated Total Reflectance Spectroscopy of New Molecular Materials
Author:
Beam, Brooke Michelle
Issue Date:
2008
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
The work embodied in this dissertation is specifically focused on the evanescent interaction of light with thin-films which has lead to two related instrument based projects: i) the Electroactive Fiber-Optic Chip (EA-FOC) and ii) Attenuated Total Reflectance (ATR) spectroscopy of novel materials. The EA-FOC combines the sensitivity of an electroactive total internal reflection element (20 to 50 times more sensitive than a transmission experiment) with the ease of use of fiber-optic based CCD spectrometers. A side-polished optical fiber, in a V-groove glass mount, forms the planar platform, which allows access to the evanescent field escaping from the fiber core. The exposed evanescent field, which was used to probe molecules or molecular assemblies supported by the platform, has an interaction area ca. 0.05 cm squared. Thin-film and bulk absorbing samples, and waveguide modeling calculations were initially used to evaluate the sensitivity of the FOC platform, which was found to be analogous to ATR instrumentation. The wavelength range of the FOC platform was increased to include the near-UV and applied to monitor adsorption of a protein film. Fluorescence applications of the FOC were demonstrated using a fluorescence bioassay and a drop cast nanoparticle film. Finally, a transparent conducting oxide film, ITO, was added to the surface of the platform to complete the EA-FOC for spectroelectrochemical applications. A methylene blue redox couple and an electrodeposited ultra-thin PEDOT film were used to probe the capabilities of the EA-FOC. The EA-FOC was shown to be a multifunctional platform for advanced sensor technologies requiring absorbance, fluorescence, and electrochemical detection or a combination thereof.ATR spectroscopy of novel materials included the evaluation of two architectures: i) a pH sensitive polyelectrolyte film and ii) surface capture of a nanoparticle film. Absorbance spectra of a polyaniline/polyacetic acid self-assembled bilayer were evaluated with respect to pH and potential using ATR spectroscopy; the ultimate application of the polymer signal transduction layer was to monitor proton transport across a lipid-bilayer. Additionally, ATR spectroscopy was used to monitor adsorption of pyridine capped nanoparticles on a silyl-propyl-thiol modified surface.
Type:
text; Electronic Dissertation
Keywords:
Fiber Optics; ATR
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Chemistry; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Armstrong, Neal R.
Committee Chair:
Armstrong, Neal R.

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleWaveguide Sensor Platforms: A) Development of the Electroactive Fiber-Optic Chip and B) Attenuated Total Reflectance Spectroscopy of New Molecular Materialsen_US
dc.creatorBeam, Brooke Michelleen_US
dc.contributor.authorBeam, Brooke Michelleen_US
dc.date.issued2008en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractThe work embodied in this dissertation is specifically focused on the evanescent interaction of light with thin-films which has lead to two related instrument based projects: i) the Electroactive Fiber-Optic Chip (EA-FOC) and ii) Attenuated Total Reflectance (ATR) spectroscopy of novel materials. The EA-FOC combines the sensitivity of an electroactive total internal reflection element (20 to 50 times more sensitive than a transmission experiment) with the ease of use of fiber-optic based CCD spectrometers. A side-polished optical fiber, in a V-groove glass mount, forms the planar platform, which allows access to the evanescent field escaping from the fiber core. The exposed evanescent field, which was used to probe molecules or molecular assemblies supported by the platform, has an interaction area ca. 0.05 cm squared. Thin-film and bulk absorbing samples, and waveguide modeling calculations were initially used to evaluate the sensitivity of the FOC platform, which was found to be analogous to ATR instrumentation. The wavelength range of the FOC platform was increased to include the near-UV and applied to monitor adsorption of a protein film. Fluorescence applications of the FOC were demonstrated using a fluorescence bioassay and a drop cast nanoparticle film. Finally, a transparent conducting oxide film, ITO, was added to the surface of the platform to complete the EA-FOC for spectroelectrochemical applications. A methylene blue redox couple and an electrodeposited ultra-thin PEDOT film were used to probe the capabilities of the EA-FOC. The EA-FOC was shown to be a multifunctional platform for advanced sensor technologies requiring absorbance, fluorescence, and electrochemical detection or a combination thereof.ATR spectroscopy of novel materials included the evaluation of two architectures: i) a pH sensitive polyelectrolyte film and ii) surface capture of a nanoparticle film. Absorbance spectra of a polyaniline/polyacetic acid self-assembled bilayer were evaluated with respect to pH and potential using ATR spectroscopy; the ultimate application of the polymer signal transduction layer was to monitor proton transport across a lipid-bilayer. Additionally, ATR spectroscopy was used to monitor adsorption of pyridine capped nanoparticles on a silyl-propyl-thiol modified surface.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectFiber Opticsen_US
dc.subjectATRen_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineChemistryen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorArmstrong, Neal R.en_US
dc.contributor.chairArmstrong, Neal R.en_US
dc.contributor.committeememberMendes, Sergio B.en_US
dc.contributor.committeememberSaavedra, S. Scotten_US
dc.contributor.committeememberAspinwall, Craig A.en_US
dc.contributor.committeememberZheng, Zhipingen_US
dc.contributor.committeememberGhosh, Indraneelen_US
dc.identifier.proquest2583en_US
dc.identifier.oclc659748514en_US
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