Comparative Study Of The Tribological And Oxidative Properties Of Alpdmn Quasicrystals And Their Cubic Approximants, 2017 Carnegie Mellon University
Comparative Study Of The Tribological And Oxidative Properties Of Alpdmn Quasicrystals And Their Cubic Approximants, Chris Mancinelli, Jeff S. Ko, Cynthia J. Jenks, Patricia A. Thiel, Amy R. Ross, Thomas A. Lograsso, Andrew J. Gellman
Thomas A. Lograsso
An experimental comparison has been made between the properties of the surfaces of an Al70Pd21Mn9quasicrystal and its Al48Pd42Mn10 approximant. The Al70Pd21Mn9 sample was a single grain icosahedral quasicrystal cut to expose its five-fold symmetric (000001) surface. The approximant was polycrystalline β-phase Al48Pd42Mn10, which has a CsCl-type cubic structure. Surfaces of both were prepared under ultra-high vacuum (UHV) conditions and then used for comparative measurements of their frictional properties and oxidation rates. Both materials are oxidized by reaction with O ...
Self-Organized Molecular Films With Long-Range Quasiperiodic Order, 2017 Université de Lorraine
Self-Organized Molecular Films With Long-Range Quasiperiodic Order, Vincent Fournée, Émilie Gaudry, Julian Ledieu, Marie-Cécile De Weerd, Dongmei Wu, Thomas A. Lograsso
Thomas A. Lograsso
Self-organized molecular films with long-range quasiperiodic order have been grown by using the complex potential energy landscape of quasicrystalline surfaces as templates. The long-range order arises from a specific subset of quasilattice sites acting as preferred adsorption sites for the molecules, thus enforcing a quasiperiodic structure in the film. These adsorption sites exhibit a local 5-fold symmetry resulting from the cut by the surface plane through the cluster units identified in the bulk solid. Symmetry matching between the C60 fullerene and the substrate leads to a preferred adsorption configuration of the molecules with a pentagonal face down, a feature unique ...
Achieving Bicontinuous Microemulsion Like Morphologies In Organic Photovoltaics, 2017 University of Texas at Austin
Achieving Bicontinuous Microemulsion Like Morphologies In Organic Photovoltaics, Dylan Kipp, Olga Wodo, Baskar Ganapathysubramanian, Venkat Ganesan
It is believed that the optimal morphology of an organic solar cell may be characterized by cocontinuous, interpenetrating donor and acceptor domains with nanoscale dimensions and high interfacial areas. One well-known equilibrium morphology that fits these characteristics is the bicontinuous microemulsion achieved by the addition of block copolymer compatibilizers to flexible polymer–polymer blends. However, there does not exist design rules for using block copolymer compatibilizers to produce bicontinuous microemulsion morphologies from the conjugated polymer/fullerene mixtures typically used to form the active layer of organic solar cells. Motivated by these considerations, we use single chain in mean field simulations ...
Electronic And Magnetic Properties Of Carbon-Based And Boron-Based Nano Materials, 2017 Clark Atlanta University
Electronic And Magnetic Properties Of Carbon-Based And Boron-Based Nano Materials, Rosi Gunasinghe
Electronic Theses & Dissertations Collection for Atlanta University & Clark Atlanta University
The structural and electronic properties of covalently and non-covalently functionalized graphene are investigated by means of first-principles density-functional-theory. The electronic characteristics of non-covalently functionalized graphene by a planar covalent organic framework (COF) are investigated. The aromatic central molecule of the COF acts as an electron donor while the linker of the COF acts as an electron acceptor. The concerted interaction of donor acceptor promotes the formation of planar COF networks on graphene. The distinctive electronic properties of covalently functionalized fluorinated epitaxial graphene are attributed to the polar covalent C–F bond. The partial ionic character of the C–F bond ...
Processing And Characterization Of Nanocomposites Prepared By High Torque Melt Mixing, 2017 Clark Atlanta University
Processing And Characterization Of Nanocomposites Prepared By High Torque Melt Mixing, Lionel W. Cross Jr
Electronic Theses & Dissertations Collection for Atlanta University & Clark Atlanta University
The rapid development of polymer nanocomposites has received extensive attention over the last few decades. The ability to alter functionalities of composites, dramatically improving properties and performance at low filler content creates flexibility in designing materials for advanced applications in various industrial fields. This work focuses on nanocomposites relevant to the packaging and aerospace industries.
This work evaluated the ability to homogeneously distribute nanomaterials into a polymer matrix, understand the effects on rheological properties, understand changes to microstructure and effects, and characterize properties of resulting nanocomposite. High torque melt mixing was used to disperse surface modified cellulose nanocrystals in a ...
Design And Fabrication Of Nanostructures For The Enhancement Of Photovoltaic Devices, 2017 University of New Orleans
Design And Fabrication Of Nanostructures For The Enhancement Of Photovoltaic Devices, Richard M. Prevost Iii
University of New Orleans Theses and Dissertations
In 2012 the net world electricity generation was 21.56 trillion kilowatt hours. Photovoltaics only accounted for only 0.1 trillion kilowatt hours, less than 1 % of the total power. Recently there has been a push to convert more energy production to renewable sources. In recent years a great deal of interest has been shown for dye sensitized solar cells. These devices use inexpensive materials and have reported efficiencies approaching 12% in the lab. Here methods have been studied to improve upon these, and other, devices. Different approaches for the addition of gold nanoparticles to TiO2 films were studied ...
Adsorption And Wetting In Model Mesoporous Silicas And In Complex Metal Oxide Catalysts, 2017 Seton Hall University
Adsorption And Wetting In Model Mesoporous Silicas And In Complex Metal Oxide Catalysts, Karthik Jayaraman
Seton Hall University Dissertations and Theses (ETDs)
The surface of most metal oxides is covered by hydroxyl groups which influence many surface phenomena such as adsorption and wetting, catalysis and surface reactions. Surface chemistry of silica is a subject of exhaustive studies owing to a wide variety of practical applications of silica. In Chapter 1, a brief review of classification, synthesis and characterization of silica is provided. The hydroxylation of silica surface i.e the number of hydroxyl (-OH) groups on the surface is of utmost importance for its practical applications. In Chapter 2, a brief introduction to surface hydration of silica is provided followed by the ...
Synthesis And Properties Of Transition-Metal Carbides From Structured Carbon Precursors, 2017 University of Wyoming
Synthesis And Properties Of Transition-Metal Carbides From Structured Carbon Precursors, Kenneth E. Madsen
Honors Theses AY 16/17
Transition metal carbides are known to have interesting chemical and physical properties, however the majority of research into these compounds has focused on nano-structured materials and thin films. This report investigates the feasibility of producing pure carbides from macroscopically structured carbon sources with dimensions greater than 500 nm. The primary carbon sources for this investigation are buckypaper, a paper-like material composed of compressed multi-walled carbon nano-tubes (MWCNT’s), compressed discs of graphitic nano-platelets, and hollow carbon spheres. Through a novel synthetic method, pure carbides were produced from each of these carbon sources. These carbide materials were then investigated to determine ...
Synthesis And Functionalization Of Small Silver Nanoparticles, 2017 Department of Chemistry, Boise State University
Synthesis And Functionalization Of Small Silver Nanoparticles, Chris Menter, Jeunghoon Lee, Sarah Rhen, Elton Graugnard, Bernard Yurke, William Knowlton, Will Hughes, Wan Kuang
William L. Hughes
Metal nanoparticles in general exhibit interesting properties due to their small sizes. This response shows up as an intense absorption band in the visible region making metallic nanoparticles ideal probes for medical imaging as well as for countless other applications. Functionalizing metallic nanoparticles with DNA enables targeted labeling, controlled by their base sequence. Another purpose of functionalization is to attach the nanoparticle to a DNA substrate allowing controlled bottom up engineering of nanoscale devices. Gold or gold-encapsulated silver is usually used for these purposes instead of bare silver due to the ease with which silver is oxidized although silver nanoparticles ...
Functionalized Silica Gel For Adsorption Of Cesium From Solution, 2017 East Tennessee State University
Functionalized Silica Gel For Adsorption Of Cesium From Solution, Kenneth Marshall Seaton Iii
Electronic Theses and Dissertations
Mesoporous silica gel containing embedded phosphotungstic acid (PTA) was synthesized by sol-gel co-condensation of tetraethyl orthosilicate with PTA in acidic media. The obtained material had high Brunauer-Emmett-Teller Theory (BET) surface area and pore volume. A characteristic band of the Keggin structure of PTA was present in its FT-IR spectrum while its X-ray diffraction patterns were absent. This proved the embedding of PTA on a sub-molecular level and not as a second phase. Acidic sites were determined by neutralization with base in aprotic solvent, followed by titration of the remaining base with an acid. The material demonstrated high adsorption capacity of ...
Effect Of Chain Rigidity On Network Architecture And Deformation Behavior Of Glassy Polymer Networks, 2017 University of Southern Mississippi
Effect Of Chain Rigidity On Network Architecture And Deformation Behavior Of Glassy Polymer Networks, Kyler Reser Knowles
Processing carbon fiber composite laminates creates molecular-level strains in the thermoset matrix upon curing and cooling which can lead to failures such as geometry deformations, micro-cracking, and other issues. It is known strain creation is attributed to the significant volume and physical state changes undergone by the polymer matrix throughout the curing process, though storage and relaxation of cure-induced strains remain poorly understood. This dissertation establishes two approaches to address the issue. The first establishes testing methods to simultaneously measure key volumetric properties of a carbon fiber composite laminate and its polymer matrix. The second approach considers the rigidity of ...
An Investigation Of The Use Of Cerium And Polyhedral Oligomeric Silsesquioxanes For The Protection Of Polymeric Epoxy Compounds In The Low Earth Orbit Environment, 2017 University of Southern Mississippi
An Investigation Of The Use Of Cerium And Polyhedral Oligomeric Silsesquioxanes For The Protection Of Polymeric Epoxy Compounds In The Low Earth Orbit Environment, Jessica Miriam Piness
Low Earth orbit presents many hazards for composites including atomic oxygen, UV radiation, thermal cycling, micrometeoroids, and high energy protons. Atomic oxygen and vacuum ultraviolet radiation are of concern for space-bound polymeric materials as they degrade the polymers used as matrices for carbon fiber composites, which are used in satellites and space vehicles due to their high strength to weight ratios. Epoxy-amine thermosets comprise a common class of matrix due to processability and good thermal attributes. Polyhedral oligomeric silsesquioxanes (POSS) have shown the ability to reduce erosion in polyimides, polyurethanes, and other polymers when exposed to atomic oxygen. The POSS ...
Controlled Synthesis And Utilization Of Metal And Oxide Hybrid Nanoparticles, 2017 University of Arkansas, Fayetteville
Controlled Synthesis And Utilization Of Metal And Oxide Hybrid Nanoparticles, Cameron Cowgur Crane
Theses and Dissertations
This dissertation reports the development of synthetic methods concerning rationally-designed, hybrid, and multifunctional nanomaterials. These methods are based on a wet chemical, solution phase approach that utilizes the knowledge of synthetic organic and inorganic chemistry to generate building blocks in solution for the growth of nanocrystals and hybrid nanostructures. This work builds on the prior knowledge of shape-controlled synthesis of noble metal nanocrystals and expands into the challenging realm of the more reactive first row transition metals. Specifically, a microemulsion sol-gel method was developed to synthesize Au-SiO2 dimers as precursors for the synthesis of segmented heterostructures of noble metals that ...
Improving Water Barrier Properties Of Epoxy Coatings With Addition Of Graphene Oxide, 2017 College of William and Mary
Improving Water Barrier Properties Of Epoxy Coatings With Addition Of Graphene Oxide, Sang H. Kim
Undergraduate Honors Theses
Epoxy coating paint is commonly used in metal coatings in aircraft and marine constructions due to its excellent mechanical properties and chemical resistance. However, being in a harsh environment, they are susceptible to degradation by water which significantly reduces the lifetime of the coatings. To better protect the material from corrosion, stress, degradation and absorption of water, nanofillers can be incorporated to improve the barrier properties. This paper explores the effect of incorporating graphene oxide (GO) as a nanofiller and the effect of different functionalization and surface modification of graphene oxide on reducing the water vapor permeability and water absorption ...
Catalyzed Synthesis Of Zinc Clays By Prebiotic Central Metabolites, 2017 University of Kentucky
Catalyzed Synthesis Of Zinc Clays By Prebiotic Central Metabolites, Ruixin Zhou, Kaustuv Basu, Hyman Hartman, Christopher J. Matocha, S. Kelly Sears, Hajatollah Vali, Marcelo I. Guzman
Chemistry Faculty Publications
How primordial metabolic networks such as the reverse tricarboxylic acid (rTCA) cycle and clay mineral catalysts coevolved remains a mystery in the puzzle to understand the origin of life. While prebiotic reactions from the rTCA cycle were accomplished via photochemistry on semiconductor minerals, the synthesis of clays was demonstrated at low temperature and ambient pressure catalyzed by oxalate. Herein, the crystallization of clay minerals is catalyzed by succinate, an example of a photoproduced intermediate from central metabolism. The experiments connect the synthesis of sauconite, a model for clay minerals, to prebiotic photochemistry. We report the temperature, pH, and concentration dependence ...
Synthesis, Characterization, And Properties Of Graphene-Based Hybrids With Cobalt Oxides For Electrochemical Energy Storage And Electrocatalytic Glucose Sensing, Sara C. Botero Carrizosa
Masters Theses & Specialist Projects
A library of graphene-based hybrid materials was synthesized as novel hybrid electrochemical electrodes for electrochemical energy conversion and storage devices and electrocatalytical sensing namely enzymeless glucose sensing. The materials used were supercapacitive graphene-family nanomaterials (multilayer graphene-MLG; graphene oxide-GO, chemically reduced GO-rGO and electrochemical reduced GOErGO) and pseudocapacitive nanostructured transition metal oxides including cobalt oxide polymorphs (CoO and Co3O4) and cobalt nanoparticles (CoNP). These were combined through physisorption, electrodeposition, and hydrothermal syntheses approaches. This project was carried out to enhance electrochemical performance and to develop electrocatalytic platforms by tailoring structural properties and desired interfaces. Particularly, electrodeposition and hydrothermal synthesis facilitate chemically-bridged ...
Where Do New Materials Come From? Neither The Stork Nor The Birds And The Bees! In Search Of The Next “First Material”, 2017 University of South Carolina
Where Do New Materials Come From? Neither The Stork Nor The Birds And The Bees! In Search Of The Next “First Material”, Gregory Morrison, Dileka Abeysinghe, Justin B. Felder, Shani Egodawatte, Timothy Ferreira, Hans Conrad Zur Loye
Journal of the South Carolina Academy of Science
Materials discovery and optimization has driven the rapid technological advancements that have been observed in our lifetimes. For this advancement to continue, solid-state chemists must continue to develop new materials. Where do these new materials come from? In this review, we discuss the approaches used by the zur Loye group to discover the next “First Material”, a new material exhibiting a desired or not previously observed property that can be optimized for use in the technologies of tomorrow. Specifically, we discuss several crystal growth techniques that we have used with great success to synthesize new materials: the flux growth method ...
Use Of Porous Elastomer Foams To Support Long Term Three Dimensional Neuronal Cultures, 2017 Kent State University - Kent Campus
Use Of Porous Elastomer Foams To Support Long Term Three Dimensional Neuronal Cultures, Richard M. Cukelj, Elda Hegmann, Ernest Freeman, Jennifer Mcdonough, Robert Clements
Undergraduate Research Symposium
In order to effectively study the interactions that occur between neurons found in the brain, spatially and after an extended period of time, it is necessary to have reliable, repeatable studies. This is difficult to accomplish through conventional two-dimensional cell culture techniques, but three dimensional (3D) elastomer foams satisfy these criteria. Here we present a platform to study complex neuronal networks for extended periods in vitro. Elastomer foams were constructed with pore sizes ranging from 150μm to 400μm with 40μm secondary pores which allowed human neuroblastoma cells (SH-SY5Y) to adhere and interact with the foam and be sustained for long ...
A Ship-In-A-Bottle Strategy To Synthesize Encapsulated Intermetallic Nanoparticle Catalysts: Exemplified For Furfural Hydrogenation, Raghu V. Maligal-Ganesh, Chaoxian Xiao, Tian Wei Goh, Lin-Lin Wang, Jeffrey Gustafson, Yuchen Pei, Zhiyuan Qi, Duane D. Johnson, Shiran Zhang, Franklin Feng Tao, Wenyu Huang
Duane D. Johnson
Intermetallic compounds are garnering increasing attention as efficient catalysts for improved selectivity in chemical processes. Here, using a ship-in-a-bottle strategy, we synthesize single-phase platinum-based intermetallic nanoparticles (NPs) protected by a mesoporous silica (mSiO2) shell by heterogeneous reduction and nucleation of Sn, Pb, or Zn in mSiO2-encapsulated Pt NPs. For selective hydrogenation of furfural to furfuryl alcohol, a dramatic increase in activity and selectivity is observed when intermetallic NPs catalysts are used in comparison to Pt@mSiO2. Among the intermetallic NPs, PtSn@mSiO2 exhibits the best performance, requiring only one-tenth of the quantity of Pt used ...
Cytotoxic And Antimicrobial Effects Of Silver-Containing Surfaces, 2017 Rowan University
Cytotoxic And Antimicrobial Effects Of Silver-Containing Surfaces, Sarah Goderecci
Theses and Dissertations
This study examines applications of sputtered silver coatings as alternatives to traditional antibiotic treatments. Given the increase in reports of antibiotic-resistant bacteria, new treatments and coatings for in-dwelling medical devices such as catheters and orthopedic implants are necessary. Silver oxide films were deposited onto Ti surfaces to examine the efficacy of such coatings against a variety of bacterial species both in vitro and in vivo. Bacterial growth studies showed that coatings exhibited antimicrobial activity against a range of bacterial species acting either in a bacteriostatic or bactericidal mechanism, depending on the target. Limited toxicity to in vitro mammalian cells was ...