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You searched for +publisher:"University of Georgia" +contributor:("Marcus Lay"). Showing records 1 – 2 of 2 total matches.

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University of Georgia

1. Shim, Jihye. Spectroscopic and scanning probe studies of single-walled carbon nanotubes.

Degree: PhD, Chemistry, 2009, University of Georgia

The main topic of this dissertation is the spectroscopic and scanning probe studies of single-walled carbon nanotubes (SWNTs). Current synthetic methods for SWNT growth have limitations such as impurities, poor dispersibility in aqueous solvents, and the lack of ordered arrays. This dissertation includes a three part study to discuss the improvement of the limitations. The first part demonstrates multiple cycles of centrifugation as a method for nondestructive purification. Atomic force microscopy(AFM) and spectroscopies show this mild purification to be effective in order to obtain unbundled and purified high-aspect ratio SWNTs. In second part of this dissertation, the effect of Nafion on the dispersion of SWNT suspensions in bisolvents is discussed. Nafion is an ambipolar dispersant consisting of hydrophilic and hydrophobic groups. Nafion was used as a polymeric dispersant of SWNT suspensions in water/ethanol or water/isopropanol. The defect of SWNT-Nafion suspensions decreased in an aqueous solution with addition of alcohol due to improved dispersion. The debundling of SWNT-Nafion suspensions in water/alcohol also was demonstrated by blue-shifted peaks in near-infrared (NIR) spectroscopy. In the final section, well-ordered arrays of SWNT networks were investigated by depositing carbon nanotubes on self-assembled molecule-coated substrates. Aminosilane and aminothiol were coated on Si/SiO2 and Au substrates, respectively, to produce self-assembled monolayers (SAMs). An improved surface morphology with decreased defects occurred when a high concentration of self-assembled molecules was absorbed for a long period of time. Advisors/Committee Members: Marcus Lay.

Subjects/Keywords: Single-walled carbon nanotubes (SWNTs)

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APA (6th Edition):

Shim, J. (2009). Spectroscopic and scanning probe studies of single-walled carbon nanotubes. (Doctoral Dissertation). University of Georgia. Retrieved from http://purl.galileo.usg.edu/uga_etd/shim_jihye_200908_phd

Chicago Manual of Style (16th Edition):

Shim, Jihye. “Spectroscopic and scanning probe studies of single-walled carbon nanotubes.” 2009. Doctoral Dissertation, University of Georgia. Accessed September 16, 2019. http://purl.galileo.usg.edu/uga_etd/shim_jihye_200908_phd.

MLA Handbook (7th Edition):

Shim, Jihye. “Spectroscopic and scanning probe studies of single-walled carbon nanotubes.” 2009. Web. 16 Sep 2019.

Vancouver:

Shim J. Spectroscopic and scanning probe studies of single-walled carbon nanotubes. [Internet] [Doctoral dissertation]. University of Georgia; 2009. [cited 2019 Sep 16]. Available from: http://purl.galileo.usg.edu/uga_etd/shim_jihye_200908_phd.

Council of Science Editors:

Shim J. Spectroscopic and scanning probe studies of single-walled carbon nanotubes. [Doctoral Dissertation]. University of Georgia; 2009. Available from: http://purl.galileo.usg.edu/uga_etd/shim_jihye_200908_phd


University of Georgia

2. Vairavapandian, Deepa. Formation of platinum thin films by electrochemical ALD and 2D networks of carbon nanotubes for electrochemical applications.

Degree: PhD, Chemistry, 2009, University of Georgia

The main topic of this dissertation is the formation nanostructures for catalysis applications by electrochemical methods. First part of the thesis deals with the formation of Pt thin films by electrochemical atomic layer deposition method (EC-ALD). The electrochemical deposition techniques are advantageous over the vacuum phase techniques because of low cost involved and temperature (ambient) used to make thin films. However the bulk electrodeposition method doesn’t offer atomic level control to the formation of thin films. The thin films growth ends up 3 dimensional leading to rough Pt films. Hence we propose a modification in the electrodeposition technique using surface limited redox replacement method. In this method, a sacrificial layer of less noble metal such as copper is deposited on the gold substrate at under potential (UPD). The resultant monolayer of copper is replaced by Pt by flowing Pt at open circuit potential. Since UPD results in one atomic layer of copper, we expect to get one atomic layer of Pt formed by the SLRR process. Copper forms UPD on Pt as well as Au. So the SLRR process is repeated any number of times depending on the thickness of Pt film needed. Home made flow cell system is used for this study. In the second part of the thesis, we focus on fabricating carbon nanotube networks as support for catalyst materials. In order to make efficient use of carbon nanotubes as catalyst support, control on the density and defects on the carbon nanotubes need to be controlled. We propose using novel room temperature deposition method called ‘Laminar flow depoosition’ (LFD) method. In this method carbon nanotube is deposited on silane coated glass slides by coating the slides with carbon nanotube/surfactant solution and then drying in the presence of nitrogen. The amount of tubes deposited is controlled by concentration of solution and time of deposition. We show the possibility of making carbon nanotube electrodes with varying electrochemical behavior by controlling the density. Cyclic voltammetry studies show the evolution of micro or macro electrode behavior depending on the density of network. Also the amount of Pt deposition depends on the defects on the carbon nanotubes. We show that acid treatment can be used to engineer the extent of defect formation. Raman studies show the formation of defects by acid treatment. By combining the LFD and acid treatment, we are able to tailor the carbon nanotube networks. Advisors/Committee Members: Marcus Lay.

Subjects/Keywords: Electrochemical atomic layer deposition; Surface limited redox replacement; Single walled carbon nanotubes; Laminar flow deposition; Atomic force microscopy; cyclic voltammetry

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Vairavapandian, D. (2009). Formation of platinum thin films by electrochemical ALD and 2D networks of carbon nanotubes for electrochemical applications. (Doctoral Dissertation). University of Georgia. Retrieved from http://purl.galileo.usg.edu/uga_etd/vairavapandian_deepa_200912_phd

Chicago Manual of Style (16th Edition):

Vairavapandian, Deepa. “Formation of platinum thin films by electrochemical ALD and 2D networks of carbon nanotubes for electrochemical applications.” 2009. Doctoral Dissertation, University of Georgia. Accessed September 16, 2019. http://purl.galileo.usg.edu/uga_etd/vairavapandian_deepa_200912_phd.

MLA Handbook (7th Edition):

Vairavapandian, Deepa. “Formation of platinum thin films by electrochemical ALD and 2D networks of carbon nanotubes for electrochemical applications.” 2009. Web. 16 Sep 2019.

Vancouver:

Vairavapandian D. Formation of platinum thin films by electrochemical ALD and 2D networks of carbon nanotubes for electrochemical applications. [Internet] [Doctoral dissertation]. University of Georgia; 2009. [cited 2019 Sep 16]. Available from: http://purl.galileo.usg.edu/uga_etd/vairavapandian_deepa_200912_phd.

Council of Science Editors:

Vairavapandian D. Formation of platinum thin films by electrochemical ALD and 2D networks of carbon nanotubes for electrochemical applications. [Doctoral Dissertation]. University of Georgia; 2009. Available from: http://purl.galileo.usg.edu/uga_etd/vairavapandian_deepa_200912_phd

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