Publication Date

2020

Document Type

Dissertation

Committee Members

Sharmila M. Mukhopadhyay, Ph.D. (Advisor); Nadagouda N. Mallikarjuna, Ph.D. (Committee Member); Willie F. Harper, Jr., Ph.D. (Committee Member); Hong Huang , Ph.D. (Committee Member); H. Daniel Young, Ph.D. (Committee Member)

Degree Name

Doctor of Philosophy (PhD)

Abstract

The goal of this project is to investigate fabrication approaches and structure-property relationships of porous and flexible hierarchical hybrid solids suitable for advanced surface-active devices. Multi-scale hierarchical carbon materials are being fabricated by strong covalent attachment of multiwall carbon nanotube(MWCNTs) arrays on flexible carbon fabric substrates in order to enhance the surface area per unit volume. This was done using chemical vapor deposition (CVD) after functionalizing the surface with a plasma-derived nano-oxide coating. Structural and chemical characterization is performed using scanning electron microscope(SEM), energy dispersive spectroscopy(EDS) and x-ray photoelectron spectroscopy(XPS). Surface area estimates have been made by building structural models from Electron Microscopy data and subsequently validated with direct measurement with BET isotherm analyses. It is seen that calculated specific surface area (SSA) of the material via mass increase during the CVD process is in good agreement with BET gas adsorption measurement of the SSA. It has been shown that further modification of these surfaces is very effective for tailoring their wettability for selective infiltration of different fluids. These structures have been infiltrated with responsive polymers such as Poly(N-isopropylacrylamide(PNIPAM)s to fabricate smart stimuli-responsive composites. In addition, palladium nanoparticles(PdNPs) have been attached onto the nanotube carpets. Particle distribution, size variation, and structures have be investigated using Scanning Electron Microscopy (SEM) & Energy Dispersive Spectroscopy (EDS). X-ray photo spectroscopy (XPS) was employed for bonding state analysis. In-depth understanding of catalytic behavior of these hybrid nanocatalysts (Fabric-CNT-Pd system) has been performed by investigating the catalytic reduction of a model water contaminant triclosan(TCS). The reaction rates, efficiency, and durability have been studied using High Performance Liquid Chromatography (HPLC) and Mass Spectroscopy (MS). Results clearly show unprecedented chemical reduction rates of TCS, implying that PdNPs on these hierarchical porous materials have application potential in next generation nano catalysts suitable for water purification devices.

Page Count

248

Year Degree Awarded

2020


Included in

Engineering Commons

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