Physical Sciences and Mathematics Commons^™

Synthesis And Characterization Of Hydroxy-Functionalized Copper Indium Disulfide Quantum Dots, Julia Schexnayder

WWU Honors College Senior Projects

Quantum dots offer tunable electronic and optical properties due to the quantum confinement effect, making them desirable for various applications. However, their native hydrophobic form requires surface chemistry modification for certain applications. This research explores the method of ligand exchange using 11-mercapto-1-undecanol for improving the stability of copper indium disulfide (CIS) quantum dot (QD) nanoparticles in polar environments. The effects of this ligand exchange on QD chemical composition, optical properties, hydroxy-reactivity, and hydrodynamic radius are characterized. Analysis of characterization results indicates successful surface modification through hydroxyfunctionalization, as confirmed by 1H-NMR and IR spectroscopy. The desired optical properties of the QDs …

Surface Modification Of Polypropylene Nonwoven With Chitosan, Tio$_{2}$, And Ag Nanoparticles For The Removal Of Acid Dye From Water, Aminoddin Haji, Mohsen Hadizadeh, Masoumeh Ferdosi

Turkish Journal of Chemistry

In this study, polypropylene nonwoven was coated with chitosan after being activated by oxygen/argon low-pressure plasma. The chitosan-treated sample (PP-Ch) was coated with TiO$_{2}$ nanoparticles by a pad-dry method. Silver nanoparticles were in situ synthesized on the chitosan-TiO$_{2}$-coated sample by a chemical reduction method. The morphology of each of the samples mentioned above was evaluated by FESEM. The efficiency of each sample in the removal of C.I. Acid Brown 248 from aqueous media was evaluated. The PP-Ch sample removed 90% of the dye at pH=3. Coating the PP-Ch sample with TiO$_{2}$ and silver nanoparticles improved the dye removal efficiency under …

Fabrication And Characterization Of Novel Agnps Functionalized With Chlorothymol (C@Agnps), Lirim Sopaj

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In this study, novel silver nanoparticles (AgNPs) were successfully synthesized and functionalized with an antibacterial agent, namely chlorothymol (denoted C@AgNPs). The resulting colloid (C@AgNPs) was purified by two comparative methods: ultrafiltration and ultracentrifugation. Ultrafiltration proved to be more efficient in purifying and size selecting (10 kD filter) and concentrating the C@AgNPs than ultracentrifugation. The physicochemical properties of the filtered C@AgNPs were then characterized by UV-Vis absorption spectroscopy, inductively coupled plasma optical emission spectroscopy (ICP-OES), Raman spectroscopy, Cytoviva hyperspectral imaging, and Scanning electron microscopy. These measurements confirmed the functionalization of the core AgNPs with chlorothymol and suggest the proposed mechanism of …

Characterization Of Functionalized Carbon Nanotubes And Polystyrene/Cnt Composites Prepared With Microwave-Induced Polymerization, Allen Hulette

Electronic Theses and Dissertations

The use of carbon nanotubes in polymer composites can increase the mechanical properties of the resulting product. Carbon nanotubes are known to have chemical interactions that make them attracted to one another and fall out of solution. To reduce this agglomeration and disperse the mechanical properties throughout the composite, functional groups are covalently added to the carbon nanotubes. Another known property of carbon nanotubes is their ability to absorb microwaves and convert it into other forms of energy. This research investigates the effects of carbon nanotube absorption of microwaves and initiation of styrene monomer polymerization. Grignard reactions are used to …

Influence Of The Spatial Distribution Of Cationic Functional Groups At Nanoparticle Surfaces On Bacterial Viability And Membrane Interactions, Yongqian Zhang, Natalie V. Hudson-Smith, Seth D. Frand, Meghan S. Cahill, Larissa S. Davis, Vivian Feng, Christy L. Haynes, Robert J. Hamers

Faculty Authored Articles

While positively charged nanomaterials induce cytotoxicity in many organisms, much less is known about how the spatial distribution and presentation of molecular surface charge impact nanoparticle–biological interactions. We systematically functionalized diamond nanoparticle surfaces with five different cationic surface molecules having different molecular structures and conformations, including four small ligands and one polymer, and we then probed the molecular-level interaction between these nanoparticles and bacterial cells. Shewanella oneidensis MR-1 was used as a model bacterial cell system to investigate how the molecular length and conformation of cationic surface charges influence their interactions with the Gram-negative bacterial membranes. Nuclear magnetic resonance (NMR) …

Amino-Functionalized Mesostructured Cellular Foam Silica: A Highly Efficient And Recyclable Catalyst In The Knoevenagel Condensation Reaction, Dong Hao, Hongyuan Yang, Tengfei Zhang, Qing Liu

Turkish Journal of Chemistry

Mesostructured cellular foam silica was functionalized by an amino group (MCF-NH$_{2})$ using the postsynthesis grafting method and utilized as a recyclable catalyst for the Knoevenagel reaction to afford $\alpha $, $\beta $-unsaturated compounds. The catalyst was systematically characterized by various analyses such as nitrogen adsorption, X-ray diffraction, Fourier transform infrared spectrophotometry, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, and Hammett indicator method. The results showed that MCF-NH$_{2}$ catalyst was successfully prepared with a high surface area of 215 m$^{2}$ g$^{-1}$ and a large pore volume of 1.37 cm$^{3}$ g$^{-1}$. Compared with the nonfunctionalized MCF sample, the window and cell …

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 …

Barrier Properties Of Polymer Nanocomposites With Graphene Oxide And Its Derivatives: Mechanism And Applications In Anticorrosive Coatings, Yidan Guan

Dissertations

Metallic devices made from steel or aluminum are subjected to deterioration by environmental contaminants over time. As one of the corrosion control methods, organic coatings show many advantages due to their low cost, versatility, decoration aesthetics and effective protections. Corrosion protection theories and failure modes of organic coatings are still not fully understood due to complicated interactions in the coating-metal-environment system, however, it is widely agreed that the barrier nature of polymeric materials towards aggressive species, such as oxygen, water, electrolyte, plays a key role. Improved barrier property of polymer nanocomposites (PNCs) with two-dimensional (2D) carbon filler, graphene and graphene …

Solvation Enhances The Distinction Between Carboxylated Armchair And Zigzag Single-Wall Carbon Nanotubes (Swnt-Cooh), Tapas Kar, Upendra Adhikari, Steve Scheiner, Ajit K. Roy, Renato L. T. Parreira, Pedro A. De S. Bergamo, Giovanni F. Caramori, Felipe S. S. Schneider

Chemistry and Biochemistry Faculty Publications

The effect of various solvents on the structures and properties of carboxylated SWNTs has been explored using the Same Level Different Basis Set approach (SLDB), where B3LYP functional of density functional theory (DFT) was applied. Armchair (4,4) and zigzag (8,0) and (9,0) tubes were considered as the test bed. In order to simulate varying concentration of –COOH groups, one to five acids groups were placed at one end of these tubes. These samples were placed in different solvents (namely, CS2, THF and water) with varying polarity and results were compared with gas-phase properties. Similar to the gas-phase, zigzag tubes also …

Oxidation Of Substituted Catechols At The Air-Water Interface: Production Of Carboxylic Acids, Quinones, And Polyphenols, Elizabeth A. Pillar, Marcelo I. Guzman

Chemistry Faculty Publications

Anthropogenic activities contribute benzene, toluene, and anisole to the environment, which in the atmosphere are converted into the respective phenols, cresols, and methoxyphenols by fast gas-phase reaction with hydroxyl radicals (HO(•)). Further processing of the latter species by HO(•) decreases their vapor pressure as a second hydroxyl group is incorporated to accelerate their oxidative aging at interfaces and in aqueous particles. This work shows how catechol, pyrogallol, 3-methylcatechol, 4-methylcatechol, and 3-methoxycatechol (all proxies for oxygenated aromatics derived from benzene, toluene, and anisole) react at the air-water interface with increasing O3(g) during τc ≈ 1 μs contact time and contrasts their …

Synthesis Of New Fullerene Derivatives For Photovoltaic And Biological Applications, Edison Castro

Open Access Theses & Dissertations

Functionalized fullerenes exhibit improved solubility and different chemical and physical properties that allow applications in multiple fields such as photovoltaic and biological applications. Currently, perovskite solar cells (PSCs) are the most rapidly developing type of solar cells with certified efficiencies rising from 3.8% in 2009 to 22.1% in 2016. The good electron transporting and solution processable properties of most fullerene derivatives make them the most popular electron transporting materials (ETMs) in inverted perovskite solar cells (PSCs).

The work is reported in 11 chapters. We start with a fullerene overview followed by cleaver and elegant methodologies that allow the synThesis of …

Site-Specific Functionalization Of Corannulene : Tailoring Structures And Properties, Cristina Dubceac

Legacy Theses & Dissertations (2009 - 2024)

Bowl-shaped polycyclic aromatic hydrocarbons (also referred to as buckybowls or π-bowls) are curved polyarenes that are structurally related to fullerenes. Corannulene, the smallest buckybowl which maps onto a one-third of the surface of C60, provides a great platform for functionalization. Various synthetic methods have been developed over the years to give access to a wealth of corannulene derivatives with many different properties and practical applications. In this work, we report on the controlled functionalization of the corannulene interior, while also employing the addition of different functionalities to its periphery for fine-tuning of the packing and bowl properties.

Toward The Synthesis Of Functionalized Poly (Ether Ether Ketone): Monitoring The Meta-Fluorine Displacement In 3,5,4’-Trifluorobenzophenone, Giovanni Covarrubias

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The synthesis of functionalized, linear poly (ether ether ketone), tailored to be semi-crystalline and soluble in a variety of organic-solvents was explored. Nucleophilic aromatic substitution was a chemical reaction method used to condense 3,5,4’-trifluorobenzophenone (TFK) with four different phenols at its para-positioned carbon-fluorine site: 4-methoxyphenol, 3-aminophenol, 4-bromophenol, and m-cresol. Further poly-condensation of functionalized TFK occurred at the meta-positioned carbon-fluorine sites with 4,4’-Bis[4-hydroxyphenoxy] benzophenone (Big A2) and 4,4’-difluorobenzophenone at molar equivalents of 1 to 0.5, respectively. The reaction afforded products that became insoluble in solvents needed for nuclear magnetic resonance spectroscopic (e.g. DMSO-d6) analysis. The lack of desirable compounds compelled the …

Water-Assisted Oxygen Activation During Selective Oxidation Reactions, Hung-Vu Tran, Hieu A. Doan, Bert D. Chandler, Lars C. Grabow

Chemistry Faculty Research

The selective functionalization of hydrocarbons with oxygen to produce valuable commodity chemicals is inherently challenging, because of the thermodynamic stability of the complete combustion products. Emerging green synthesis routes and sustainable energy production also rely on the success of selective oxidation reactions. As one of the unselective by-products, water is always present under reaction conditions and numerous studies indicate that the catalytic activity and selectivity of selective oxidation reactions may be tuned by judiciously controlling the water content during the reaction. Some experimentally verified examples include the preferential oxidation of carbon monoxide, direct hydrogen peroxide synthesis, propene epoxidation and alcohol …

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 …

Functionalization Of Metal Oxide Surfaces Through Chemical Reactions And Physical Adsorption, Gabriel C. Graffius

Seton Hall University Dissertations and Theses (ETDs)

The synthesis of high surface area metal oxides is an area of extensive research with potential applications in catalysis, adsorption, and materials chemistry. The functionalization of a material’s surface can dramatically change its physical and chemical properties. The research described herein is built on the foundation of traditional techniques used for synthesis, characterization, and functionalization of metal oxides and develops new mechanisms and materials for the functionalization of surfaces.

We began with Methyl-terminated poly(dimethylsiloxanes) (PDMSs), which are typically considered to be inert and not suitable for surface functionalization reactions because of the absence of readily hydrolysable groups. Nevertheless, these siloxanes …

Functional Nanoparticles At Interfaces: Emulsion Stabilization And Triggered Inversion, Caroline Laure Marie Miesch

Doctoral Dissertations

Encapsulation of materials can be performed through the stabilization of fluid-fluid interfaces and the formation of emulsion droplets, which is commonly achieved with surfactants, including small molecules and polymers, as well as particles that are, typically, micron-scale in diameter. The worked contained in this dissertation centered on droplets that are stabilized by nanoparticles, including metallic nanoparticles and semiconductor quantum dots, which bring the conductive and fluorescent properties inherent to such nanoparticles into the droplet construction. Double emulsion droplets, both oil-in-water-in-oil (o/w/o) and water-in-oil-in-water (w/o/w) were formed using nanoparticles as the only surfactant in solution. Different types of nanoparticles were found …

Preparation Of Pt/Dna-Mwcnts/Gc Electrode And Its Electrocatalytic Activity Toward H2O2 Reduction, Li-Li Fan, Li-Na Wu, Zhi-Yu Qu, Dan-Feng Liu, Jun-Ming Zhang, Si-Ming Fan, You-Jun Fan

Journal of Electrochemistry

The DNA-multi-walled carbon nanotubes (MWCNTs)/glassy carbon (GC) electrode was prepared by modifying the DNA functionalized MWCNTs composite on a GC electrode. A novel non-enzymatic H₂O₂ sensing electrode was fabricated by electrodepositing Pt nanoparticles on the DNA-MWCNTs/GC electrode. The modified electrodes were characterized by scanning electron microscope (SEM). The response properties of the sensing electrode to H₂O₂ were investigated by cyclic voltammetry and chronoamperometry. The results indicated that the sensing electrode exhibited a good linear relationship between response current and H₂O₂ concentration in the range of 0.04 ~ 18.07 mmol·L^-1 with …

Physicochemical Modifications And Applications Of Carbon Nano-Onions For Electrochemical Energy Storage, Rituraj Borgohain

Rituraj Borgohain

Carbon nano-onions (CNOs), concentrically multilayered fullerenes, are prepared by several different methods. We are studying the properties of two specific CNOs: A-CNOs and N-CNOs. A-CNOs are synthesized by underwater arc discharge, and N-CNOs are synthesized by high-temperature graphitization of commercial nanodiamond. In this study the synthesis of A-CNOs are optimized by designing an arc discharge aparatus to control the arc plasma. Moreover other synthesis parameters such as arc power, duty cycles, temperature, graphitic and metal impurities are controlled for optimum production of A-CNOs. Also, a very efficient purification method is developed to screen out A-CNOs from carboneseous and metal impurities. …

Poly(Vinyl Chloride) Functionalization By Aliphatic And Aromatic Amines: Application To The Extraction Of Some Metal Cations, Fayçel Ammari, Faouzi Meganem

Turkish Journal of Chemistry

The aim of this study was to evaluate the efficiency of 3 new polymers obtained by functionalization of a commercial poly(vinyl chloride) by grafting amino-alkyl and amino-aryl groups to extract some metal cations from aqueous solutions. The percentage of extraction was determined by comparing the initial electrical conductivity of the aqueous solution containing the studied metal and that of the aqueous solution at the extraction equilibrium. One of the obtained polymers gave an extraction ratio of Sn^{2+} = 87.1 %, which highlight the importance of the substitution of chlorine atoms by diethylenetriamine groups. These results were compared with those obtained …

A Rheological Examination Of Polymer Composites: Including Functionalized Carbon Nanotubes, Viable Polyurethane Alternates, And Contact Lens Hydrogels, Bernard Knudsen

USF Tampa Graduate Theses and Dissertations

From medicine to aerospace, innovation in multiple fields will not occur without addressing current questions that still exist in polymer behavior and manipulation. This dissertation represents the research carried out over the course of three separate experiments using rheometry as the key technique to explore the behavior of polymer composites. In all three studies, polymer composites were investigated for changes to their known physical properties caused through the addition of a filler or functionalization.

Chapter Two examines the possibility of enhancing poly(4-methyl-1-pentene) through the use of soluble carbon nanotubes. In this series of experiments, carbon nanotubes were covalently functionalized using …

Physicochemical Modifications And Applications Of Carbon Nano-Onions For Electrochemical Energy Storage, Rituraj Borgohain

Theses and Dissertations--Chemistry

Carbon nano-onions (CNOs), concentrically multilayered fullerenes, are prepared by several different methods. We are studying the properties of two specific CNOs: A-CNOs and N-CNOs. A-CNOs are synthesized by underwater arc discharge, and N-CNOs are synthesized by high-temperature graphitization of commercial nanodiamond. In this study the synthesis of A-CNOs are optimized by designing an arc discharge aparatus to control the arc plasma. Moreover other synthesis parameters such as arc power, duty cycles, temperature, graphitic and metal impurities are controlled for optimum production of A-CNOs. Also, a very efficient purification method is developed to screen out A-CNOs from carboneseous and metal impurities. …

Functional, Degradable Polyester Materials Synthesized From Poly(Epsilon-Caprolactone-Co-2-Oxepane-1,5-Dione): An Investigation Into The Derivatization, Self Assembly, And Degradation Behavior Of Poly(Epsilon-Caprolactone)-Based Materials, Rhiannon K. Iha

Arts & Sciences Electronic Theses and Dissertations

Biocompatible, degradable polymers possessing a high degree of complexity are an extremely desirable target for many applications. In order to further develop the range and utility of materials made from aliphatic polyesters, poly(epsilon-caprolactone-co-2-oxepane-1,5-dione) (P(CL-co-OPD)) was used as a polymeric precursor for the construction of a series of functional polyester-based materials. By taking advantage of the electrophilic ketone moieties characteristic of the OPD repeat unit, small molecule and polymer grafts were attached to the PCL backbone through the formation of both hydrazone and ketoxime ether linkages. This work has focused on both the synthesis and characterization of functional, degradable polyesters, including …

Controlled Functionalization Of Crystalline Polyolefins And Their Application In Soluble Polymer Support, Jihoon Shin

UNLV Theses, Dissertations, Professional Papers, and Capstones

Functionalization of polyolefins has been recognized as a useful methodology for the generation of new materials with a wide range of applications. Recently, crystalline or semi-crystalline polyolefins have drawn increasing attention in both industrial and academic fields as one of the most interesting engineering plastics, due to their remarkable physical and mechanical properties. This dissertation describes: (1) novel methods for the direct postfunctionalization of crystalline polyolefins to introduce functionality, (2) characterizations for the functionalized polymers to analyze their structures, molecular-weight properties, thermal properties, and hydrophilicity, and (3) an application of the modified crystalline polystyrene as a soluble polymer support for …

Synthesis Of Alkylthiol-Containing Fluorene Derivatives For Gold Nanoparticle Functionalization, Sriram Mukundarajan

Electronic Theses and Dissertations

A novel synthetic methodology has been developed for attaching fluorene derivatives, containing different types of electron donating and accepting groups at the 2 and 7 positions, to gold nanoparticles of different sizes by exploiting the affinity of the thiol functional group for gold. The distance between the dye and nanoparticles was varied by introducing two alkyl chains containing different number of carbon atoms at the 9 position on the fluorene ring system. The methodology that was developed gave enough scope for performing Radiative Decay Engineering (RDE) studies, in order to investigate the impact of gold nanoparticles on the singlet oxygen …

Ultra-Fast Formation Of Stable Nanoparticle Film Assemblies, Dan Sheibley, Renee Szymanik, Michael C. Leopold

Chemistry Faculty Publications

Novel assembled films of monolayer-protected clusters (MPCs) can be grown on gold and glass substrates with a 20-fold higher efficiency than established procedures. Thick MPC films grown using this new method, which can easily be scaled up or automated, are extremely stable and have properties identical to traditionally formed nanoparticle films, including unique quantized double layer charging effects. This new procedure for growing nanoparticle films shares the versatility of the traditional method but exhibits accelerated growth attributed to highly efficient sorption and mobility of metal ion linkers within swelled films and improved mass transfer of nanoparticles to assembly sites. Concentration …

The Functionalization Of Thermally Stable Third-Order Nlo Chromophores, James Richard Sawyer

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There is a need to functionalize NLO chromophore systems to incorporate them into polymeric matricies by covalent attachment. The functionalization of a series of NLO chromophores based on the N,N-diphenyl-N-[7-(2-benzothiazolyl)-9,9-diethyl-2- fluorenyl ]amine structure has been investigated. All the chromophores were synthesized from the intermediate chromophore N-phenyl-N-[4-(4-bromophenyl)phenyl ]-N-[7-(2- benzothiazolyl)-9,9-diethyl-2-fluorenyl ]amine which was prepared by a six-step process. Bromination of fluorene yielded 2,7-dibromo-fluorene which could be converted to 2,7- dibromo-9,9-diethylfluorene by alkylation with ethyl iodide in DMSO.Reaction of 2,7- dibromo-9,9-diethylfluorene with one equivalent of butyl lithium followed by reaction with DMF provides 2-bromo-7-formyl-9,9-diethylfluorene.Condensation of 2-bromo-7- formyl-9,9-diethylfluorene and 2-aminobenzenethiol in DMSO results in …