Chemistry Commons^™

Characterization Of S-Swcnt/Pf-Pd Dispersions And Networks, Tamara N. El-Hayek Ms., Jeffrey Blackburn, Andrew Ferguson, Tammy Pheuphong

STAR Program Research Presentations

Single-Walled Carbon Nanotubes (SWCNTs) are being investigated for their use in a wide variety of renewable energy applications. Their unique physical properties contribute to desirable traits such as a high carrier mobility, strong optical absorption and tunable electronic band gap. Unfortunately, due to variability in certain parameters, SWCNTs are limited in their application. The major drawback is that SWCNTs are variable in size and type and typical synthetic methods are not selective. As a result, selective methods must be developed in order to sort these tubes and extract those which are desirable for a particular application. Though there are several …

Studies On Purification And Functionalization Of Carbon Nanotubes And Their Aqueous Phase Behavior, Zheqiong Wu

Dissertations

Carbon nanotubes (CNTs) are known to have unique mechanical, thermal and electrical properties which make them attractive for a wide range of applications ranging from batteries to sensors. CNTs are rolled up graphene sheets where the single-walled CNTs (SWCNTs) and multi-walled CNTs (MWCNTs) are classified according to the number of concentric rings. In this dissertation, the focus is on several different aspects of MWCNTs. These include purification, functionalization and colloidal behavior.

MWCNTs are insoluble in solvents and therefore some degree of functionalization is required prior to their real-world applications. Oxidation debris is generated during carboxylation which is usually the first …

Segmentation And Additive Approach: A Reliable Technique To Study Noncovalent Interactions Of Large Molecules At The Surface Of Single‐Wall Carbon Nanotubes, Ana M. Torres, Steve Scheiner, Ajit K. Roy, Andrés M. Garay-Tapia, John J. Bustamante, Tapas Kar

Chemistry and Biochemistry Faculty Publications

This investigation explores a new protocol, named Segmentation and Additive approach (SAA), to study exohedral noncovalent functionalization of single-walled carbon nanotubes (SWNTs) with large molecules, such as polymers, bio-molecules etc, by segmenting the entire system into smaller units to reduce computational cost. A key criterion of the segmentation process is the preservation of the molecular structure responsible for stabilization of the entire system in smaller segments. Noncovalent interaction of linoleic acid (LA, C18H32O2), a fatty acid, at the surface of a (10,0) zigzag nanotubeis considered for test purposes. Three smaller segmented models have been created from the full (10,0)-LA system …

Incorporating Carbon Nanotubes Into Carbon Fiber Via Surface Modification, Robert Benjamin Ripy

Masters Theses

Ever more advanced materials need to be designed to further the exploration of avenues of science and engineering. Metals and traditional composites are not meeting the needs of today’s stringent demands for lightweight and strong materials. There is a need for advanced materials that are lighter and stronger to replace conventional materials; carbon fiber composites became the obvious choice because of their outstanding mechanical properties. Polyacrylonitrile (PAN) based carbon fiber has reached its apex in terms of its strength to weight ratio. Carbon nanotubes (CNTs) offer a lightweight and potentially stronger alternative to PAN based fibers. However, it is difficult …

Removal Of Perfluorooctanoic Acid From Water Using Primitive, Conventional And Novel Carbonaceous Sorbent Materials, Christopher K. Brown

Theses and Dissertations

Polyfluoroalkyl Substances (PFAS), like perfluorooctanoic acid, have been used for the last 50 years in a wide variety of industrial processes and consumer-based products, including polymer additives, lubricants, fire retardants and suppressants, pesticides, and surfactants (Buck et al. 2015). The Department of Defense (DoD) has used PFAS-based Aqueous Film Forming Foam (AFFF) at fire training facilities and aircraft hangars. AFFF has contaminated approximately 600 sites classified as fire training facilities with PFAS (Huang, 2013).

This study focused on testing the most likely carbonaceous adsorbent compounds to remediate PFAS-contaminated sites on Air Force installations. Batch tests were performed to determine the …

Toward High Performance Nanocarbon Fibers, Michaela R. Pfau

Master's Theses

High performance carbon fibers (CFs) have been a commercially available since their commercial boom in the 1970s, and are generally produced via carbonization of poly (acrylonitrile) (PAN). More recently, carbon nanomaterials like graphene and carbon nanotubes (CNTs) have been discovered and have shown excellent mechanical, thermal, and electrical properties due to their sp² carbon repeating structure. Graphene and CNTs can both be organized into macroscopic fibers using a number of different techniques, resulting in fibers with promising mechanical performance that can be readily multifunctionalized. In some cases, the two materials have been combined, and the resulting hybrid fibers have …

Transparent, Stretchable, And Conductive Swnt Films Using Supramolecular Functionalization And Layer-By-Layer Self-Assembly, Tricia B. Carmichael, Akhil Vohra, R. Stephen Carmichael, Patigul Imin, Mokhtar Imit, Jagan Singh Meena, Alex Adronov

Chemistry and Biochemistry Publications

We demonstrate films of single-walled carbon nanotubes (SWNTs) on the elastomer polydimethylsiloxane (PDMS) that are stretchable, conductive, and transparent. Our fabrication method uses the supramolecular functionalization of SWNTs with conjugated polyelectrolytes to generate aqueous dispersions of positively- and negatively-charged SWNTs, followed by layer-by-layer self-assembly onto a PDMS substrate. Adding bilayers of positively- and negatively-charged SWNTs to the surface causes the sheet resistance and the % transmittance of the film to both progressively decrease. The sheet resistance decreases sharply in the first five bilayers as the layer-by-layer process efficiently establishes the percolation network, whereas the % transmittance declines more gradually. Films …

Degradation And Exciton Energy Transfer Studies In Single-Walled Carbon Nanotube Bundles, Abhishek Gottipati

Legacy Theses & Dissertations (2009 - 2024)

Single walled carbon nanotubes (SWNTs) due to their unique optical behavior, large surface area, robust mechanical strength and electrical properties make them one of the ideal candidates for sensing and opto-electronic applications. In this work, we explore the energy transfer (exciton energy transfer-EET) phenomena occurring between nanotubes in bundles, using resonance Raman spectroscopy.