Chemistry Commons^™

Doping Of Conjugated Polymers: Preparation, Characterization And Device Fabrication, Kan Tang

Dissertations

Semiconducting conjugated polymers (CPs) as emerging materials for advanced electronic applications such as sensors, OPVs, and OEFTs has become an intriguing research topic in the past decades. It opens a new avenue of “flexible” electronics, which has shown great potential in next-generation electronic devices.

However, due to the nature of CP materials and related solution processing techniques, unlike almost perfectly crystalline silicon materials, CPs in the solid-state often exhibit much lower crystallinity if it is not complete amorphous, which severely hinder the electronic property and optical property of the materials. The crystallinity of CPs in a film is often uniquely …

Vortex-Oriented Ferroelectric Domains In Snte/Pbte Monolayer Lateral Heterostructures, Kai Chang, John W. D. Villanova, Jing-Rong Ji, Souvik Das, Felix Kuster, Salvador Barraza-Lopez, Paolo Sessi, Stuart S. P. Parkin

Physics Faculty Publications and Presentations

Heterostructures formed from interfaces between materials with complementary properties often display unconventional physics. Of especial interest are heterostructures formed with ferroelectric materials. These are mostly formed by combining thin layers in vertical stacks. Here the first in situ molecular beam epitaxial growth and scanning tunneling microscopy characterization of atomically sharp lateral heterostructures between a ferroelectric SnTe monolayer and a paraelectric PbTe monolayer are reported. The bias voltage dependence of the apparent heights of SnTe and PbTe monolayers, which are closely related to the type-II band alignment of the heterostructure, is investigated. Remarkably, it is discovered that the ferroelectric domains in …

Characterization Of Lamellar Liquid Crystal Emulsifiers In Topical Creams Containing A Novel Solvent, Melinda Joanna Sutton

Graduate Theses/Dissertations

Diethylene glycol monoethyl ether (DEGEE) is a promising solvent component in topical cream formulations due to its superior solubilizing abilities with certain active pharmaceutical ingredients. One of the goals of this study is to characterize the effects of pH on the physical and chemical stabilities of topical cream formulations containing particularly high concentrations of DEGEE by characterizing a full topical pH profile of 3.5 – 9.0. The second goal is to evaluate the presence, amount, and characteristics of lyotropic liquid crystals (LLCs), molecularly structured in a lamellar phase, in a model cream emulsion utilizing polarized light microscopy (PLM). The presence …

Synthesis Of The Diazonium Zwitterionic Polymer/Monomer For Use As The Electrolyte In Polymer Electrolyte Membrane (Pem) Fuel Cells, Josiah Marshall

Electronic Theses and Dissertations

My research goals are to synthesize new zwitterionic perfluorosulfonimide (PFSI) monomer/polymers. They are expected to replace traditionally used perfluorosulfonic acid (PFSA) polymers as the electrolyte in PEM fuel cells. For the PFSI monomer preparation, we designed a nine-step synthesis route. Thus far, I have successfully completed the synthesis of 4- (2-bromotetrafluoroethoxy)-benzenesulfonyl amide, 4-acetoxybenzenesulfonic acid sodium salt, and 4-chlorosulfonyl phenyl acetate. The coupling reaction of 4-(2-bromotetrafluoroethoxy)- benzenesulfonyl amide with 4-chlorosulfonyl phenyl acetate, was troublesome due to slow reaction kinetics and byproducts. Additionally, I did a methodology study for the homopolymerziation of the perfluoro 3(oxapent-4-ene) sulfonyl fluoride monomer. We compared the weight …

Comparison Of Chalk Types And Their Ghosting Effects, Felicienne Alexandre, Shoshanna Coon, Kirk Manfredi

Summer Undergraduate Research Program (SURP) Symposium

Chalkboard ghosting is a faint image on a chalkboard's surface after writing is erased. Many types of chalk leave a positive image, while the Crayola An-du-septic Anti-dust chalk leaves a negative image. To better understand what cause the ghosting effects, two different types of Crayola chalk (regular and anti-dust) were investigated. Raman spectroscopy and infrared (IR) spectroscopy were used to determine the majority material the chalk was made of, by comparison with pure substances. To identify the organic compound binders holding the chalk sticks together, pulverized chalk was immersed in 40 mL of toluene for at least 30 minutes. After …

Fabrication Of Electrospun Nanofiber Composite Of G-C3n4 And Au Nanoparticles As Plasmonic Photocatalyst, Dipendu Saha, Pasquale Gismondi, Kurt W. Kolasinski, Samantha L. Shumlas, Sylvie Rangan, Babak Eslami, Amy Mcconnell, Taevaughn Bui, Kayla Cunfer

Chemistry Faculty Publications

In this research, we have fabricated a composite nanofiber mat of plasmonic photocatalyst consisting of g-C3N4, gold nanoparticles (AuNPs) and random nanofibers of polyvinylidene fluoride (PVDF) by electrospinning. The structure and chemical properties of the nanofiber mat were investigated in detail by ESEM, TEM, AFM, XPS, FTIR, XRD, TGA, PL spectroscopy and UV-Vis reflectance spectra. Imaging of the composite map confirmed that the fiber diameter was in the range of 100-400 nm with the g-C3N4 size in the range of 2-8 μm. Backscattered (Zcontrast) electron imaging in ESEM revealed that the AuNP particle size is in the range of 60-160 …

Designing Atomic Edge Structures In 2d Transition Metal Dichalcogenides For Improved Catalytic Activity, Raymond R. Unocic, Xiahan Sang, Guoxiang Hu, Victor Fung, Jingsong Huang, Matthew G. Boebinger, Kai Xiao, Panchapakesan Ganesh

Publications and Research

Designing new materials for functional applications depends upon our ability to understand and correlate the materials structure and chemistry to functional material properties. This is even more important for two-dimensional (2D) materials where thicknesses are on the order of a single atom to a few-atomic layers; therefore, any structural or chemical modification at these length scales can have a profound effect on modifying physical and chemical properties. 2D transition metal dichalcogenides (TMDs) such as MoS2 have emerged as a promising catalyst for the hydrogen evolution reaction with defects such as vacancies and edges being linked to high catalytic active sites …

Degumming Of Hemp Fibers Using Combined Microwave Energy And Deep Eutectic Solvent, Bulbul Ahmed

LSU Master's Theses

Hemp is considered as one of the sustainable agricultural fiber materials. Degumming or surface modification of hemp bast is needed to produce single fibers for ensuing textile and industrial applications. The traditional degumming process necessitates a high amount of alkali, which causes detrimental environmental pollution. This study offers a new method to degum hemp fibers with reduced use of harmful alkali and precious water resources. In this work, hemp bast fibers were degummed by using combined microwave energy and deep eutectic solvent (DES). The properties of hemp fibers manufactured by this method were investigated and compared with the traditional alkali …

The Development And Application Of Instrumental Methods For The Identification Of Materials And Processes Used In The Manufacture Of Orotone, Hand-Colored Orotone, And Silvertone Photographs, Ivanny Jeannette Jácome-Valladares

Dissertations and Theses

Orotone photographs are positive photographic images on glass with a gold-colored metallic coating or backing. Although the materials and process used in the production of orotones have been previously documented, there is limited published scientific research on the subject. This study focused on expanding those published works by analyzing a greater number of photographs, including eleven orotones, four hand-colored orotones, two silvertones, and one uncoated orotone. The photographs, dating from the early to mid-20^th century, were from the University of Washington (UW) Libraries' collection, except for one orotone that was from the Portland Art Museum.

X-ray Fluorescence (XRF) spectroscopy, …

Photovoltages In Polycrystalline Mosaic Solar Cells, Steluta A. Dinca, Eric A. Schiff

Chemistry - All Scholarship

In some thin-film solar cells the light-absorbing layer is a mosaic of crystalline grains whose boundaries run from the back to the front of the cell. We used the semiconductor modeling software Sesame to do numerical calculations of the optoelectronic properties of such cells assuming that recombination of minority photocarriers occurs primarily at the grain boundaries. The work complements analytical results for diffusion-limited recombination at grain boundaries and dislocations. We chose idealized n-CdS/p-CdTe solar cells for illustration. We find that the open-circuit voltage, V_oc, under illumination declines logarithmically with increasing ratio D/θ², where D is the …

Design Of Antioxidant Monomer, Augustine Osilamah Yusuf

Masters Theses & Specialist Projects

Reactive oxygen species such as hydrogen peroxide are present at the sites of inflammation in the body. Degradable polymeric nanoparticles have shown great promise in a range of biomedical applications which include preferential delivery of therapeutics to such inflamed sites. We are working towards a new class of materials expected to have tunable degradation rates in the presence of hydrogen peroxide. These new materials consist of three parts: degradable linkages, antioxidant groups, and unreactive filler monomers such as methylmethacrylate. We have synthesized a polymerization initiator with a degradable linkage, and we have shown that using this initiator to synthesize another …

Phase-Field Modeling Of The Polymer Membrane Formation Process For Micro- And Ultra-Filtration, Michael Rosario Cervellere

Graduate Theses and Dissertations

Porous polymer membrane filters are widely used in separation and filtration process. Micro- and ultra-filtration membranes are commonly used in biopharmaceutical applications such as filtering viruses and separating proteins from a carrier solution. The formation of these membrane filters via phase inversion is a complex and interconnected process where varying casting conditions can have a wide variety of effects on the final membrane morphol- ogy. Tailoring membrane filters for specific performance characteristics is a tedious and time consuming process. The time and length scales of membrane formation make it extremely difficult to experimentally observe membrane formation. Modeling the membrane formation …

Metal-Assisted Catalytic Etching (Mace) For Nanofabrication Of Semiconductor Powders, Kurt W. Kolasinski

Chemistry Faculty Publications

Electroless etching of semiconductors has been elevated to an advanced micromachining process by the addition of a structured metal catalyst. Patterning of the catalyst by lithographic techniques facilitated the patterning of crystalline and polycrystalline wafer substrates. Galvanic deposition of metals on semiconductors has a natural tendency to produce nanoparticles rather than flat uniform films. This characteristic makes possible the etching of wafers and particles with arbitrary shape and size. While it has been widely recognized that spontaneous deposition of metal nanoparticles can be used in connection with etching to porosify wafers, it is also possible to produced nanostructured powders. Metal-assisted …

Harnessing Surface Chemistry And Instabilities In Silicone Elastomers To Synthesize Adaptive Systems With Mechanically Tunable Surface Properties And Functionality, Ali Jamal Mazaltarim

Department of Chemistry: Dissertations, Theses, and Student Research

Material interfaces are of critical importance to numerous fields, including nanomaterials, electronics, microfluidics, synthesis, bioanalysis, pharmaceuticals, and catalysis, and they have been extensively researched. The materials used in these fields are often rigid/hard (such as silicon wafers) resulting in static surface properties. Consequently, the chemical/morphological properties of a surface may be modified using synthetic or mechanical means to tailor the interfacial properties of a material (i.e., surface energy, adhesion, topography, and reactivity). Recently, emphasis has been placed on designing dynamic materials with adaptive interfacial properties that respond to a variety of environmental stimuli. To this end, the surface chemistry and …

Microfabrication And Electrochemical Characterization Of A Novel Su-8 Probe With An Array Of Individually Addressable Electrodes Suitable For Redox Cycling Experiments In Ultra-Small Volumes, Mahsa Lotfi Marchoubeh

Graduate Theses and Dissertations

Redox cycling is an electrochemical technique that utilizes closely spaced generator and collector electrodes to cycle reversible redox species between their oxidative states. With advantages in signal amplification, selectivity of species based on their electrochemical reaction mechanism, and limited or no background subtraction, this technique is well suited for selective detection of important electrochemically active molecules such as dopamine at basal or slowly changing levels.

Miniaturized medical devices have become an area of great interest for measurement of chemicals in limited volumes with low concentrations or in sensitive tissues. A probe on a polymeric SU-8 substrate with suitable dimensions and …

Preparation Of Co1-XS-Mns@Cnts/Cnfs For Electrocatalytic Oxygen Reduction Reaction, Fang-Yan Liu, Qian Zhang, Yue-Kun Li, Feng Huang, Meng-Ye Wang

Journal of Electrochemistry

As an important cathode reaction in fuel cells and metal-air batteries, oxygen reduction reaction (ORR) is a complex reaction of slow kinetics, which severely limits performances of fuel cells and metal-air batteries. Therefore, it is of key importance to find an efficient and stable electrocatalyst to promote ORR. Carbon-based materials, which possess high conductivity, good stability and large specific surface area, are usually used in electrocatalytic ORR. However, pure carbon-based materials exhibit low efficiency. Coupling carbon-based materials with manganese (Mn) and cobalt (Co) transition metals containing 3d orbitals is an effective way to improve electrocatalytic performance. Herein, carbon nanofibers containing …

Research And Application Of Copper Electroplating In Interconnection Of Printed Circuit Board, Chong Wang, Chuan Peng, Jing Xiang, Yuan-Ming Chen, Wei He, Xin-Hong Su, Yu-Yao Luo

Journal of Electrochemistry

Copper electroplating is the key technology for manufacturing of integrated circuit, packaging substrate, printed circuit board, and other electronic interconnection components. However, the electrochemistry and mechanism of deposition growth have not been fully elucidated, and the development of additives and bath maintenance are inseparable from a large number of experiments. This article reviews recent fundamental research and application progress in copper electroplating for printed circuit board industry, and these works are mainly dedicated by the research group of Printed Circuit and Printed Electronics from University of Electronic Science and Technology of China. First of all, a brief history of copper …

Synthesis And Electrochemical Study Of Cuau Nanodendrites For Co2 Reduction, Dylan Siltamaki, Shuai Chen, Farnood Rahmati, Jacek Lipkowski, Ai-Cheng Chen

Journal of Electrochemistry

The conversion of carbon dioxide (CO₂) to carbon monoxide (CO) and other value-added products is an interesting approach for carbon-containing fuel synthesis using renewable and clean energy. The electrochemical reduction of CO₂ is one of the promising strategies for the storage of intermittent renewable energy resources. The development of electrocatalysts with high activity and stability is vital in the electrochemical CO₂ reduction process. In this study, copper and gold alloyed (CuAu) electrodes with nanodendritic structures were synthesized using a facile electrodeposition method. The CuAu nanodendrites with the atomic ratio of Cu to Au being approximately 1:1 …

Progress Of Lithium-Ion Transport Mechanism In Solid-State Electrolytes, Bing-Kai Zhang, Lu-Yi Yang, Shun-Ning Li, Feng Pan

Journal of Electrochemistry

Inorganic crystalline solid electrolytes exhibit exceptional room-temperature ionic conductivities, giving them the potential to enable all-solid-state lithium (Li) - ion batteries. Developing new high-performance electrolytes is one of the most critical challenges to realize solid-state batteries, which requires understanding how chemistry facilitates fast ionic conduction and what the Li-ion migration mechanism is in inorganic solid electrolytes. In this review, we aim to summarize recent fundamental research progress in Li-ion transport, including crystal structure, behavior of ion migration (i.e., single-ion jump and multi-ions cooperative migration), and the relationship between ion migration and microstructure.
Generally, ion transport in crystalline structure can be …

Studies And Progresses On Hole Metallization In High-Density Interconnected Printed Circuit Boards, Zhao-Yun Wang, Lei Jin, Jia-Qiang Yang, Wei-Qing Li, Dong-Ping Zhan, Fang-Zu Yang, Shi-Gang Sun

Journal of Electrochemistry

Printed circuit boards (PCBs) are almost the core components of all electronic systems. With the rapid development of sciences and technologies, PCBs are gradually developing in the direction of multi-layer, thin and high-density wiring due to the functionalization, miniaturization, lightweight and high reliability of electronic products, as well as the widespread popularization of the subminiature package such as chip scale package (CSP) and ball grid array (BGA). Therefore, High-density interconnected printed circuit boards (HDI-PCBs) arise. Hole metallization is one of the core technologies in HDI-PCBs and includes two processes composed of conductive treatment and electron electroplating. Electroless copper plating, as …

Design And Fabrication Of The Electrolytic Cell With Silicon-Based Boron-Doped Diamond Electrode And Its Feasibility ForIn-Situ Nuclear Magnetic Resonance Study, Hao Peng, Hui-Jun Sun, Zhi-You Zhou, Lin-Fan Shen, Long Huang, Shuo-Hui Cao, Shi-Gang Sun

Journal of Electrochemistry

In-situ EC-NMR technique can be used to monitor the electrochemical reaction process in real-time and to explain the reaction mechanism at the molecular level, which is a promising and non-destructive online detection technology. This article for the first time reports the design and production of in-situEC-NMR three-electrode single-chamber electrolytic cell using silicon-based boron-doped diamond (Si/BDD) as the working electrode. Research shows that the geometric size of Si/BDD electrode being 12.5 mm 1.2 mm 0.5 mm in the NMR detection zone is small and the thickness of the electrode material is thin, which accounts for the less hindrance …

Recent Advances In Glycerol Electrooxidation On Pt And Pd: From Reaction Mechanisms To Catalytic Materials, Wei-Yi Zhang, Xian-Yin Ma, Shou-Zhong Zou, Wen-Bin Cai

Journal of Electrochemistry

The conversion of glycerol to value-added products has received considerable attention recently because the booming biodiesel industry produces a large amount of glycerol as a byproduct. Among various means, electrocatalytic oxidation of glycerol is appealing owing to its environmental friendliness and high efficiency. However, electrooxidation of glycerol is very complex, involving multiple electron and proton transfer processes with many reaction pathways. How to rationally design catalysts with high selectivity toward targeted products is an overarching challenge, and of both fundamental and practical significance. In this minireview we aim to provide an overview of recent advancements in electrooxidation of glycerol focusing …

Multiple Wetting−Dewetting States Of A Water Droplet On Dual- Scale Hierarchical Structured Surfaces, Yurui Gao, Yuan Liu, Jian Jiang, Chongqin Zhu, Craig Zuhlke, Dennis Alexander, Joseph S. Francisco, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

Surfaces with microscale roughness can entail dualscale hierarchical structures such as the recently reported nano/ microstructured surfaces produced in the laboratory (Wang et al. Nature 2020, 582, 55−57). However, how the dual-scale hierarchical structured surface affects the apparent wetting/ dewetting states of a water droplet, and the transitions between the states are still largely unexplored. Here, we report a systematic large-scale molecular dynamics (MD) simulation study on the wetting/dewetting states of water droplets on various dual-scale nano/near-submicrometer structured surfaces. To this end, we devise slab-water/slab-substrate model systems with a variety of dual-scale surface structures and with different degrees of intrinsic …

Soft Lithographic Replication Of High Length-Scale Micropillars From Laser-Ablated Fused-Silica Templates, Jason Pitts

University Honors Theses

Soft lithography is a well-established route to wafer-scale reproduction of micro- and nanoscale features in a wide variety of materials. Nevertheless, micron length scales have yet to be explored, despite the potential utility of such structures. Here, polymer micropillars of 6-12 μm length, approximately 0.5-1.5 μm wide at 10 μm spacing are reproduced from a polydimethylsiloxane (PDMS) mold made from patterned cellulose acetate (CA). The patterned CA was cast from a rigid fused silica template machined by a pulsed femtosecond laser. Pore topographic features were successfully reproduced in Norland Optical Adhesive (NOA), polycaprolactone (PCL), Nafion, acrylonitrile butadiene styrene (ABS), and …

Fullerene And Tungsten Oxide Nanostructures-Based Electrocatalysts For All-Vanadium Redox Flow Batteries, Farah Ahmed El Diwany

Theses and Dissertations

The vanadium redox flow battery (VRFB) is one of the most promising long-term energy storage solutions mainly due to its long service life and the independence of its energy capacity on power rating and vice versa. However, its relatively high capital cost limits its widespread deployment. Economic analysis reveals that a high-power density VRFB with decreased cell stack size can dramatically reduce the cost. The energy efficiency of a VRFB primarily depends on the kinetics of vanadium redox reactions that take place in the stack. Therefore, studying the effect of surface chemistry of electrodes on the kinetics of each …

The Effect Of Reaction Conditions On The Nucleation And Particle Growth Of A Colloidal Covalent Organic Framework, Brendan Posson

Master's Theses

Covalent organic frameworks (COFs) are a novel class of crystalline materials with regular porosity, high specific surface area, and various linkage chemistries. Conventional chemical syntheses of these materials lead to the formation of bulk powders characterized as polycrystalline aggregates. Synthesizing these materials as colloidal systems is an effective means to prevent aggregation and achieve larger single-crystalline domain sizes. In this thesis, I describe the effect of temperature and transimination catalyst strength on COF particle nucleation and particle growth. Morphology and crystallinity of the COF-300 particles were confirmed using X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The onset of colloidal …

Formulating 3-Chloropropyltriethoxysilane Modified Silica Nanoparticle Sprays As Hydrophobic Transparent Coatings Onto Cotton Textiles, Mikaela C. S. Mendoza, Gilbert U. Yu

Chemistry Faculty Publications

Cotton textiles were transformed into hydrophobic fabrics via the application of 3-chloropropylthriethoxysilane-functionalized silica nanoparticle spray coatings. Silica particles were measured to be < 50 nm, as determined by dynamic light scattering (DLS). The incorporation of hexadecyltrimethylammonium bromide (HTAB), a surfactant, into the nanosilica alcohol-based sprays resulted in a suspension that was stable for at least a week. Stability and turbidity tests of samples point to smaller particle size (silica nanoparticles = 24.3 ± 8.5 nm) as the main contributor to possibly providing transparency, as evidenced when sprayed in colored (black) textiles, while still contributing to hydrophobicity/ superhydrophobicity of the cloth.

Facile Synthesis Of Metal Oxides, Sulphides, And Phosphides For Enhanced Energy Applications, Alfred Nkhama

Electronic Theses & Dissertations

An access to reliable, sustainable, eco-friendly and cost-effective energy supply is being challenged by the global increase in population and the rapid technological advancement. Sophisticated systems, machinery and various devices being innovated, require the steady energy supply for their operations and applicability. To have reliable energy, numerous researches are being conducted through various approaches across the world. In this research work, the facile approach in investigating and tuning the materials properties was employed to improve energy properties of metal oxides. Nanostructured NiFe-oxide and CoFe-oxide were synthesized using a facile coprecipitation method. It was revealed that; nanostructured materials have favorable structures …

Synthesis And Self-Assembly Of Amphiphilic Block Copolymers For The Fabrication Of Non-Spherical Polymersomes, Tamuka Chidanguro

Dissertations

Polymersomes, also known as polymer vesicles, have gained a lot of interest over the past two decades. These hollow spherical systems are made via the self-assembly of amphiphilic block copolymers and have found use in a range of areas from drug delivery, to cellular models, to nanoreactors. Their hollow nature allows them to carry hydrophilic cargo in their inner compartment and hydrophobic cargo in their membrane. Over the last decade, increasing efforts have focused on controlling the morphology of polymersomes. Research has shown that polymersome morphology plays an important role for instance in drug delivery, where tubular or rod-like vesicles …

Data-Driven Approaches To Complex Materials: Applications To Amorphous Solids, Dil Kumar Limbu

Dissertations

While conventional approaches to materials modeling made significant contributions and advanced our understanding of materials properties in the past decades, these approaches often cannot be applied to disordered materials (e.g., glasses) for which accurate total-energy functionals or forces are either not available or it is infeasible to employ due to computational complexities associated with modeling disordered solids in the absence of translational symmetry. In this dissertation, a number of information-driven probabilistic methods were developed for the structural determination of a range of materials including disordered solids to transition metal clusters. The ground-state structures of transition-metal clusters of iron, nickel, and …