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Functionalized Carbon Nanotubes In Hydrophobic Drug Delivery, Kun Chen

Dissertations

The direct incorporation of carboxylated carbon nanotubes (f-CNTs) into hydrophobic drug particles during their formation via anti-solvent precipitation is presented. The approach is tested using two drugs namely antifungal agent Griseofulvin (GF) and antibiotic Sulfamethoxazole (SMZ) that have very different aqueous solubility. It is observed that the f-CNTs dispersed in the water serve as nucleating sites for crystallization and are readily incorporated into the drug particles without altering crystal structure or other properties. The results show that the hydrophilic f-CNTs dramatically enhance dissolution rate for both drugs. The increased degree of functionalization leads to higher hydrophilicity and therefore faster dissolution …

Penetration Depth Variation In Atomic Layer Deposition On Multiwalled Carbon Nanotube Forests, David Alan Kane

Theses and Dissertations

Atomic Layer Deposition (ALD) of Al2O3 on tall multiwalled carbon nanotube forests shows concentration variation with the depth in the form of discrete steps. While ALD is capable of extremely conformal deposition in high aspect ratio structures, decreasing penetration depth has been observed over multiple thermal ALD cycles on 1.3 mm tall multiwalled carbon nanotube forests. SEM imaging with Energy Dispersive X-ray Spectroscopy elemental analysis shows steps of decreasing intensity corresponding to decreasing concentrations of Al2O3. A study of these steps suggests that they are produced by a combination of diffusion limited delivery of precursors with increasing precursor adsorption site …

Implemenatation Of Additive Print Manufacturing Processes For The Development Of Flexible Thermal Sensors, Vikram Shreeshail Turkani

Masters Theses

This work focuses on the design, fabrication and characterization of novel flexible thermal sensors using additive print manufacturing processes. Initially, a carbon nanotube (CNT) based negative temperature coefficient (NTC) thermistor was fabricated on a flexible polyethylene terephthalate (PET) substrate using screen and gravure printing processes. The thermistor consists of two silver (Ag) electrodes deposited using screen printing process. A CNT based sensing layer was deposited using gravure printing process on the Ag electrodes. Finally, a primary polymer and a secondary Ag encapsulation layer were deposited using screen printing process. The capability of the fabricated thermistor was investigated by measuring its …

An Introductory Study Of Solid Materials For Capture And Catalysis Of Waste Stream Chemicals, Steven Kyle Butler

Theses and Dissertations

Heterogeneous catalysts are key materials in research and industry. Herein we study two materials in different stages of development toward being applied as heterogeneous catalysts. First, MoO3SnO2 was synthesized and studied as a catalytic system similar to Sn-beta zeolites. While the Mo-based catalyst did not show similar activity to Sn-beta, it did show interesting reactivity in activating carbonyls and oxidizing organic substrates. Second, a method was developed for grafting amines onto carboxylic acid functionalized carbon nanotubes for CO2 capture. The method was successful for grafting monomer ethylamine groups onto CNT and can be further developed to allow for polymeric amine …

Graphene Foam And Helically Coiled Carbon Nanotubes As Electrodes In Energy Storage Devices, Anthony Childress

All Dissertations

Since their inception, carbon nanomaterials have been exploited for use in energy storage. The discovery of carbon nanotubes and the later isolation of graphene opened new avenues in electrode research for batteries and electric double layer capacitors (EDLCs). Their combination of flexibility, mechanical robustness, and electronic conductivity make them ideal for use as active materials and additives. My research has focused on the synthesis and implementation of helical carbon nanotubes (HCNTs) for supercapacitors and few-layer graphene in the form of graphene foam (GF) for aluminum-ion batteries. The presence of defects and dopants was controlled in each system to determine how …

Carbon Nanotube Yarn Based Dye Sensitized Solar Cells With Enhanced Electron/Hole Pair Recombination Prevention Characteristics, Glenn E. Grissom

Theses and Dissertations

Carbon nanotube yarn based solar cells (CNTYSCs) show promise in a variety of applications such as military and smart fabrics. We use a highly aligned and interwoven Carbon nanotube yarn (CNTY) for the working electrode (WE) and counter electrode (CE), to create a flexible super strong, conductive, and photo active surface for the support of a calcined TiO2 nano-solution and macro-solution deposition as a base for added functionalizations of a dye-sensitized solar cell (DSSC) that is able to maintain its flexibility and integrity. The CNT fiber based solar cells have power conversion ability that is independent of the direction of …

Fabrication And Analysis Of Multifunctional Carbon Nanotube Electrical Conductors, Andrew Robert Bucossi

Theses

Carbon nanotube (CNT) bulk conductors have been proposed as an alternative material to metals for power and data transmission applications due to their light weight, flexure tolerance, and chemical stability. However, current fabrication technologies prevent bulk CNT wires from matching the electrical properties of individual CNTs, providing opportunity for researchers to improve CNT wire fabrication.

In this work, CNT conductors have been advanced using high-purity laser-vaporized single wall carbon nanotubes (SWCNTs). Acid dispersion and extrusion of SWCNTs into a coagulant bath was used to fabricate wires and systematic modification of the process has determined that coagulation dynamics govern the resulting …

Engineering Hyaluronic Acid Carbon Nanotube Nanofibers: A Peripheral Nerve Interface To Electrically Stimulate Regeneration, Elisabeth M. Steel

Wayne State University Dissertations

Peripheral nerve injuries annually affect hundreds of thousands of people globally. Current treatments like the gold standard autograft and commercially available nerve guide conduits (NGC) are insufficient to repair long gap peripheral nerve injuries. NGCs can aid recovery but lack key microenvironment cues that promote nerve regeneration. We hypothesized that providing topographical, mechanical, and electrical guidance cues through a nanofibrous composite biopolymer would result in improved neuron growth metrics using an in vitro model. We embedded hydrophilic carbon nanotubes (CNT) within hyaluronic acid (HA) nanofibers by electrospinning. The aims of this study were (1) to define the topographical, nanomechanical, and …

Polypyrrole (Ppy) Coated Patterned Vertical Carbon Nanotube (Pvcnt) Dry Ecg Electrode Integrated With A Novel Wireless Resistive Analog Passive (Wrap) Ecg Sensor, Mohammad Jomah I. Abu Saude

Electronic Theses and Dissertations

Biopotential signals such as electroencephalography (EEG), electrocardiography (ECG or EKG), electrooculogram (EOG), and electromyography (EMG) play vital roles in health and clinical diagnoses, monitoring, and therapy. In addition, these signals are required for many nonclinical applications such as Neurofeedback and Brain-Computer Interface (BCI). The quality of the measurement relies on the electrical and mechanical properties of the electrode. Conventional wet or gel impedimetric electrodes provide an excellent signal due to the conductive fluids or gel, which reduces the skin-contact impedance and maintains contact during movement. However, they operate for a short duration; the quality of the signal degrades due to …

Heat, Charge And Spin Transport Of Thin Film Nanostructures, Devin John Wesenberg

Electronic Theses and Dissertations

Understanding of fundamental physics of transport properties in thin film nanostructures is crucial for application in spintronic, spin caloritronics and thermoelectric applications. Much of the difficulty in the understanding stems from the measurement itself. In this dissertation I present our thermal isolation platform that is primarily used for detection of thermally induced effects in a wide variety of materials. We can accurately and precisely produce in-plane thermal gradients in these membranes, allowing for thin film measurements on 2-D structures. First, we look at thermoelectric enhancements of doped semiconducting single-walled carbon nanotube thin films. We use the Wiedemann-Franz law to calculate …

Mixed Matrix Flat Sheet And Hollow Fiber Membranes For Gas Separation Applications, Nicholas W. Linck

Theses and Dissertations--Chemical and Materials Engineering

Mixed matrix membranes (MMM) offer one potential path toward exceeding the Robeson upper bound of selectivity versus permeability for gas separation performance while maintaining the benefits of solution processing. Many inorganic materials, such as zeolites, metal-organic frameworks, or carbon nanotubes, can function as molecular sieves, but as stand-alone membranes are brittle and difficult to manufacture. Incorporating them into a more robust polymeric membrane matrix has the potential to mitigate this issue.

In this work, phase inversion polymer solution processing for the fabrication and testing of asymmetric flat sheet mixed matrix membranes was employed with CVD-derived multiwall carbon nanotubes (MWCNTs) dispersed …