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dc.contributor.advisor Pasquali, Matteo
dc.creatorYoung, Colin C
dc.date.accessioned 2017-08-01T15:55:55Z
dc.date.available 2017-08-01T15:55:55Z
dc.date.created 2017-05
dc.date.issued 2017-04-21
dc.date.submitted May 2017
dc.identifier.citation Young, Colin C. "Two Studies from the Development Cycle ofMacroscopic Carbon Nanotube Materials: Rheology of Carbon Nanotubes in Superacids and Characterization of the Electrochemical Circuit Behavior of Carbon Nanotube Fiber Electrodes for Electrophysiology." (2017) Diss., Rice University. https://hdl.handle.net/1911/95986.
dc.identifier.urihttps://hdl.handle.net/1911/95986
dc.description.abstract Carbon nanotubes (CNTs) possess a variety of properties which make them attractive as building blocks for high performance multi-functional materials. The discovery that superacids such as chlorosulfonic acid (ClHSO3) act as true solvents for CNTs has led to the development of fluid processing techniques by which a variety of macroscopic CNT materials can be fabricated. This work presents two studies which are linked by the common thread of CNT materials development from acid solution precursors. The first study compares the rheology of two different CNT species in ClHSO3 as a function of concentration and frequency. The development of elastic structure with increasing solution concentration is found to depend strongly on the morphology of the liquid crystalline phase domains in the biphasic regime; physical interactions between non-interpenetrating liquid crystal domains are found to be a significant source of viscoelastic stress. An analysis of the scaling of viscoelastic behavior at short time scales, based on models of semiflexible polymer rheology, reveals that the primary contribution to the stress at short times is longitudinal tension resulting from contour fluctuations of individual CNTs; this tension-dominated stress is the primary viscoelastic stress for low concentration solutions. The second study investigates the electrochemical properties of macroscopic CNT fibers for applications in electrophysiology and cardiac medicine. CNT fibers exhibit much lower interfacial impedance with physiological saline and cardiac tissue than platinum wire of the same geometric surface area. Equivalent circuit modeling demonstrates that the low area-specific impedance of these fibers arises from a large double layer capacitance, which in turn arises from wetting of the internal porous surface area. Aging and storage conditions are shown to affect the wettability of this structure, and an electrowetting treatment is demonstrated which creates a stable increase in CNT fiber electrode performance. The specific circuit behavior of the CNT fiber is used to construct a theoretical model for CNT fiber electrode performance in cardiac tissue in vivo and to calculate a transfer function which represents the efficiency with which a cellular action potential may be transmitted through a CNT fiber between two electrically separated regions of cardiac tissue.
dc.format.mimetype application/pdf
dc.language.iso eng
dc.subjectcarbon nanotubes
chlorosulfonic acid
superacid
electrochemistry
dc.title Two Studies from the Development Cycle ofMacroscopic Carbon Nanotube Materials: Rheology of Carbon Nanotubes in Superacids and Characterization of the Electrochemical Circuit Behavior of Carbon Nanotube Fiber Electrodes for Electrophysiology
dc.contributor.committeeMember Razavi, Mehdi
dc.date.updated 2017-08-01T15:55:55Z
dc.type.genre Thesis
dc.type.material Text
thesis.degree.department Applied Physics
thesis.degree.discipline Natural Sciences
thesis.degree.grantor Rice University
thesis.degree.level Doctoral
thesis.degree.name Doctor of Philosophy
thesis.degree.major Applied Physics/Physics


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