Physical Sciences and Mathematics Commons^™

Manufacturing Of A Flexible Piezoelectric Nanogenerator By Functionalizing Polyvinylidene Fluoride With Lithium Tantalate And Multiwalled Carbon Nanotubes For Energy Harvesting And Sensing Applications, Islam Uddin Shipu

Theses and Dissertations

Mechanical energy is one of the readily accessible green energy sources that could be employed to meet the small-scale energy requirement. In order to capture mechanical energy, power the next generation of electronic gadgets, and health monitoring flexible piezoelectric nanogenerators made of light weight polymers and carbon nanotubes have drawn a lot of attention. Lithium tantalate (LiTaO3), a ferroelectric substance, was prepared here and utilized to create a flexible piezoelectric nanogenerator (FPNG). A compact piezoelectric nanogenerator that successfully transfers mechanical energy into electricity was then created using lightweight polyvinylidene fluoride (PVDF), multi-walled carbon nanotube (MWCNT), and LiTaO3 nanoparticles. To create …

Utilizing Fluorescent Nanoscale Particles To Create A Map Of The Electric Double Layer, Quintus Owen

Theses and Dissertations

The interactions between charged particles in solution and an applied electric field follow several models, most notably the Gouy-Chapman-Stern model, for the establishment of an electric double layer along the electrode, but these models make several assumptions of ionic concentrations and an infinite bulk solution. As more scientific progress is made for the finite and single molecule reactions inside microfluidic cells, the limitations of the models become more extreme. Thus, creating an accurate map of the precise response of charged nanoparticles in an electric field becomes increasingly vital. Another compounding factor is Brownian motion’s inverse relationship with size: large easily …

Novel Synthetic Strategies Toward Polyolefin-Grafted Nanoparticles, Richard Tran Ly

Theses and Dissertations

Surface functionalization of nanoparticles has proven to be a powerful and versatile strategy in the development of various materials with advanced properties. Polymer brush composition can range from complex copolymers to more simplistic polyolefin, and by functionalizing nanoparticle surfaces, mobility of distinct particles can then be tuned and, therefore, control over dispersion in a polymer matrix can be achieved. Presented in this dissertation are new synthetic strategies for the preparation of polymer nanocomposites.

The first chapter covers a novel synthetic strategy for ethylene/propylene-like copolymers grafted to silica nanoparticles. This approach utilizes Reversible Addition-Fragmentation Chain Transfer (RAFT) polymerization to promote living …

Characterization Of Ph – Responsive Nanocage Based On The Ferritin Iron Storage Protein, Satyam Singh

Theses and Dissertations

The iron-storage protein ferritin (Ftn) assembles into a protein cage structure with 24 subunits and octahedral (4-fold, 3-fold, 2-fold) symmetry. Each monomeric subunit contains a robust four-helix bundle fold. The fully assembled Ftn structure has a high degree of thermal stability (up to 100°C), a mono dispersed size (12 nm in diameter), and a large central cavity (7-8 nm in diameter). The central cavity stores ferric iron in phylogenetically diverse group of organisms, including humans. The central cavity has been used for encapsulation of cargoes such as other metals, contrast agents for imaging, small molecule drugs for therapy, …

Fabrication Of Metal-Silicon Nanostructures By Reactive Laser Ablation In Liquid, Eric J. Broadhead

Theses and Dissertations

Metal-silicon nanostructures are a growing area of research due to their applications in multiple fields such as biosensing and catalysis. In addition, silicon can provide strong support effects to metal nanoparticles while being more cost effective than traditionally used supports, like titania. Traditional wet-chemical methods are capable of synthesizing metal-silicon nanostructures with a variety of composition and nanoparticle shapes, but they often require high temperatures, toxic solvents, strong reducing agents, or need capping agents added to stabilize the nanoparticles. Laser processing is an emerging technique capable of synthesizing metal-silicon composite surfaces that offers a faster, simpler, and greener synthesis route …

Detection Of 2,4,6-Trinitrotoluene Using A Colorimetric Gold Nanoparticle Air Cassette Filter, Andrea I. Ferrer Vega

Theses and Dissertations

Trinitrotoluene (TNT) is an explosive commonly used during military and terrorist activities. Current methods to identify this compound require sampling, transport and analysis at a forensic lab using analytical instrumentation. However, on-site detection is needed to assist efforts to prevent detonation. Gold nanoparticles have been used as sensors throughout the years due to their versatility and surface enhanced Raman scattering properties in the presence of an analyte and low limits of detection. By taking advantage of the Meisenheimer complex that TNT forms in the presence of amines, it is possible to determine its presence at picogram levels. Subsequently, adhering amine …

Synthesis And Design Of Novel Polymer Grafted Nanoparticles Relevant To Drug Delivery Vehicles For Biomedical Applications, Maan Abduldiyem Hassan Al-Ali

Theses and Dissertations

The modification of inorganic nanoparticles with organic polymer chains has become a significant field of study for the engineering of advanced nanocomposite materials. This dissertation presents the design, synthesis, and characterization of novel polymer grafted silica nanoparticles as new strategies to combat bacterial resistance. Described herein is the synthesis of monomers that have been graft polymerized onto silica nanoparticles that can be used as a delivery drug vehicle for biomedical applications. The polymerization of these monomers was performed via reversible addition-fragmentation chain transfer (RAFT) polymerization. The molecular design of the RAFT agents that are attached to the surfaces of the …

Synthesis And Design Of Novel Polymer Grafted Nanoparticles Relevant To Drug Delivery Vehicles For Biomedical Application, Maan Abduldiyem Hassan Al-Ali

Theses and Dissertations

The modification of inorganic nanoparticles with organic polymer chains has become a significant field of study for the engineering of advanced nanocomposite materials. This dissertation presents the design, synthesis, and characterization of novel polymer grafted silica nanoparticles as new strategies to combat bacterial resistance. Described herein is the synthesis of monomers that have been graft polymerized onto silica nanoparticles that can be used as a delivery drug vehicle for biomedical applications. The polymerization of these monomers was performed via reversible addition-fragmentation chain transfer (RAFT) polymerization. The molecular design of the RAFT agents that are attached to the surfaces of the …

The Development Of Multi-Functional System That Combine Patterned Hydrogels, Plasmin-Degradable Nanoparticles And Stem Cells For Applications In Tissue Engineering And Growth Factors Delivery, Safaa I. Kader

Theses and Dissertations

This thesis spots the light on the development of a novel multi-functionalized system for application in tissue engineering and on-demand morphogens delivery. Three types of materials used in this study are synthetic polymer, biopolymer, and nanomaterials. Polyethylene glycol (PEG), a synthetic polymer was chosen in this study because of its high biocompatibility, non-immunogenicity, inert nature, ease of modification, and reduces protein denaturation to provide a wide range of physical and mechanical properties. Here, PEG is used one time as a hydrogel, linear polyethylene glycol-co-lactide (LPELA), and another time as peptide-PEG based nanoparticles (PxSPCP). Gelatin, a natural polymer has been widely …

Molten-Salt Synthesized Pyrochlore Nanoparticles For Multifunctional Applications, Jose P. Zuniga

Theses and Dissertations

There is a need in the scientific world to design and develop high quality nanomaterials with multifunctional applications. In this work, we explore the molten-salt method (MSS) as a new green method for the synthesis of complex metal oxides. We adjusted all synthesis parameters such as time, temperature and pH to generate an optimum La2Hf2O7 nanoparticle with a well define shape and surface. Activator ions such as Eu3+, Tb3+, Dy3+, Bi3+ and uranium ion (U4+, U6+) were used to monitor its structural and optical behavior effect when doped.

Our results showed effective quantum yield, thermal, pressure stability, near to white …

Selective Catalysis By Polymer-Supported Ruthenium Nanoparticlesand New Ligand Design For Cooperative And Bimetallic Catalysis, Seyed Hadi Nazari

Theses and Dissertations

The abstract is the summary of three different projects all centered around the generalidea of catalysis which is the general theme of research in the Michaelis laboratory. The firstproject focuses on development of a new heterogeneous catalyst for selective catalysis. In theMichaelis lab, we were interested in the potential of nanoparticle catalysts for regioselectivetransformations. We showed that polymer supported ruthenium nanoparticles performed as areliable catalyst for regioselective reduction of azide to amine. In our study of regioselectivereduction of multiple azide containing substrates, we observed that in presence of ourruthenium nanoparticle catalysts, the least sterically hindered azide group reduced to aminefunctional …

Synthesis And Characterization Of Magnetic Cabides And Oxides Nanomaterials, Hei Man Tsui

Theses and Dissertations

The design and development of nanoparticles is of great interest in the current energy and electronic industry. However, based on the current materials available the production cost can be high with insignificant magnetic and mechanical properties. Specifically, rare-earth magnetic materials composed of neodymium and samarium are known for their high magnetic performance, however, due to the cost of development there is a need to develop a versatile and cost effective material. Alternatively, cobalt carbide nanomaterials have shown to be a promising alternative for rare-earth free magnets as they exhibit comparable properties as hexaferrite magnetic materials. The primary goal of this …

Structural Transformations Of Multimetallic Nanoparticles, Guangfang Li

Theses and Dissertations

Atomic-level understanding of the structural transformations of multimetallic nanoparticles (NPs) triggered by external stimuli is of vital importance to the enhancement of our capabilities to precisely fine-tailor the key structural parameters and thereby to fine-tune the catalytic properties of the NPs. In this work, I firstly show that Au-Cu bimetallic NPs demonstrate stoichiometry-dependent architectural evolutions during chemical dealloying processes and nanoporosity-evolving percolation dealloying only occurs for Au-Cu alloy NPs with Cu atomic fractions above the parting limit. The electrochemically active surface area and the specific activity of the dealloyed nanoframes can be systematically tuned to achieve the optimal electrocatalytic activity. …

Synthesis And Characterization Of Polydiene-Grafted Nanoparticles, Zaid Mohammed Abbas Alajeeli

Theses and Dissertations

This dissertation presents the design, synthesis, and characterization of polydiene grafted nanoparticles as a way to tailor nanocomposite interfaces and properties via interface design. The polymerization of dienes was done via reversible addition fragmentation chain transfer (RAFT) polymerization. The grafting of polymer chains on the surface of silica nanoparticles can be controlled through the molecular design of the RAFT agents attached to the nanoparticles surface. The properties of the nanocomposites largely depended on the interface between the particles and the polymer matrix. In the first part of this work, the polymerization of diene monomers was done on 15 nm diameter …

Fabrication And Application Of Functional Polymer-Protein Coreshell Nanoparticles, Lin Lu

Theses and Dissertations

The study of polymer-protein nanoparticles is of increasing interest due to their various potential applications in biosensing, imaging, bioseparations, gene and drug delivery, etc. Synthetic polymers can be tailored with different functional groups and properties, therefore, they can serve as platforms to impart proteins with additional features and assist proteins to better perform biological functions. In this dissertation work, we were mainly focusing on the preparation of polymer-protein core-shell nanoparticles by synthesizing new functional polymers and assembling them with proteins for different applications. In chapter 1, a pyridine grafted diblock copolymer P(CL-g-Py)-b-PCL was prepared through ROP and CuAAC reactions. …

Synthesis, Characterization, And Enhanced Magnetic Properties Of Iron Carbide Nanomaterials, Brent M. Williams

Theses and Dissertations

Permanent magnets are classified as hard magnetic materials with the main purpose of generating flux for applications such as electric motors, turbines, and hard drives. High coercivity, magnetic remanence, and saturation values with high stability are some of the requirements for permanent magnets. Rare-earth magnets including neodymium and samarium based magnets are known to have superior magnetic properties due to their high magnetocrystalline anisotropy. However, due to the price of rare-earth materials development of alternate permanent magnets composed of inexpensive materials is an ongoing process. Previously cobalt carbide (Co_xC) have shown promise as a potential rare-earth free magnet …

Polymer Grafted Nanoparticles For Designed Interfaces In Polymer Nanocomposites, Mohammad Mohammadkhani

Theses and Dissertations

This dissertation presents the design, synthesis, and characterization of polymer nanocomposite interfaces and the property enhancement from this interface design. Through the use of reversible addition fragmentation chain transfer (RAFT) polymerization for the grafting of polymer chains to silica nanoparticles, the surface of silica nanoparticles can be manipulated to tune the properties of nanocomposites by controlling the interface between the particles and the polymer matrix.

In the first part of this work, compatibility of 15 nm silica nanoparticles grafted with different alkyl methacrylates with linear low density polyethylene was investigated. SI-RAFT polymerization of hexyl, lauryl, and stearyl methacrylate on silica …

Development And Application Of New Solid-State Models For Low-Energy Vibrations, Lattice Defects, Entropies Of Mixing, And Magnetic Properties, Jacob M. Schliesser

Theses and Dissertations

Low-temperature heat capacity data contain information on the physical properties of materials, and new models continue to be developed to aid in the analysis and interpretation of heat capacity data into physically meaningful properties. This work presents the development of two such models and their application to real material systems. Equations describing low-energy vibrational modes with a gap in the density of states (DOS) have been derived and tested on several material systems with known gaps in the DOS, and the origins of such gaps in the DOS are presented. Lattice vacancies have been shown to produce a two-level system …

Development Of Protein-Polymer Core-Shell Nanoparticles (Ppcs-Nps) As Efficient Vehicles To Deliver Therapeutic Agents Across Blood Brain Barrier (Bbb), Napat Tandikul

Theses and Dissertations

Blood Brain Barrier (BBB) plays a main role as selective barrier which controls and limits access of chemicals, molecules and therapeutic agents from blood to brain. The BBB endothelial cells are connected by Tight Junctions (TJs) which close intracellular spaces between the endothelial cells and block the free diffusion of substances, therefore many potential drugs for treating human brain diseases cannot reach the brain in sufficient concentration. Recently, many studies have thrown an interest in development of nanoparticles for delivering drugs and imaging agents across BBB. Our research group has developed protein-polymer core-shell nanoparticles (PPCS-NPs) which demonstrate great potential for …

Facile Method For Large Scale Alignment Of One Dimensional Nanoparticles And Its Biomedical Application, Sheng Feng

Theses and Dissertations

Topographical cues can profoundly affect cellular behaviors. This thesis investigate how to utilize the topographical cues generated by two techniques, flow assembly and electrospinning, to regulate cellular behaviors.

First of all, a facile and robust method to align one-dimensional (1D) nanoparticles (NPs) in large scale has been developed. Using flow assembly, representative rod-like nanoparticles, including tobacco mosaic virus (TMV), gold nanorods and bacteriophage M13, have been aligned inside capillaries by controlling flow rate and substrate surface properties. The properties of 1D NPs, such as stiffness and aspect ratio, play a critical role in the alignment. Furthermore, these hierarchically organized structures …

Modification Of Nanoparticles For Designed Interfaces, Tony Lee Neely, Jr.

Theses and Dissertations

The work contained herein, is focused on the design, synthesis, and characterization of polymer nanocomposite interfaces and the property enhancement afforded from said interface design. Through the use of reversible addition fragmentation chain transfer (RAFT) polymerization for the grafting of polymer chains to silica nanoparticles, the surface of silica nanoparticles can be manipulated to tune the properties of the nanocomposite as a whole.

In the first part of this work, heterogeneity is introduced onto the surface of silica nanoparticles via a sequential RAFT polymerization to afford a bimodal brush system. A densely grafted, short brush population is polymerized from the …

Synthesis And Characterization Of Polymer Nanomaterials Using Controlled Radical Polymerization, Lei Wang

Theses and Dissertations

This research focuses on creating and investigating polymer/organic bound interfaces on nanoparticles with advanced architectures to tailor the properties of polymer nanocomposites for various applications. Reversible addition-fragmentation chain transfer (RAFT) polymerization and a toolbox of surface functionalization from the simple to the advanced were developed to prepare the polymer nanomaterials.

In the first part (Chapter 2), a variety of RAFT agents (xanthate, dithiocarbamate and trithiocarbonate) were used to mediate the polymerizations of several classes of free radical polymerizable monomers. These monomers consist of styrene, methyl acrylate, methyl methacrylate, vinyl acetate and isoprene, which have different activities and require different classes …

Synthesis And Characterization Of Cobalt Carbide Based Nanomaterials, Zachary Huba

Theses and Dissertations

Permanent magnets are used heavily for multiple applications in industry and current electronic technologies. However, the current permanent landscape is muddled by high cost of materials and insufficient magnetic or thermal properties. The primary focus of this dissertation work is the synthesis and optimization of a new permanent magnetic material, in the form of cobalt carbide nanomaterials. The optimization revolved around controlling the crystal phase and particle shape of synthesized cobalt carbide particles; these parameters have significant impact on the observed magnetic properties of magnetic nanoparticles. Co₃C was identified to be the preferred crystal phase, leading to better …

Formation And Analysis Of Zinc Oxide Nanoparticles And Zinc Oxide Hexagonal Prisms And Optical Analysis Of Cadmium Selenide Nanoparticles, Jared M. Hancock

Theses and Dissertations

In this dissertation, methods to synthesize ZnO are reported. First, zinc oxide nanoparticles were synthesized with small amounts of transition metal ions to create materials called dilute magnetic semiconductors (DMS). We employed a low temperature sol-gel method that produces ZnO nanoparticles of reproducible size and incorporates cobalt, nickel, and manganese ions into the nanoparticles. Conditions were controlled such that a range of amounts of Co, Ni, and Mn were incorporated. The incorporation was tracked by color changes in the white ZnO powder to blue for Co, green for Ni and yellow for Mn. XRD measurements showed the nanoparticles were on …

Laser Vaporization Methods For The Synthesis Of Metal And Semiconductor Nanoparticles; Graphene, Doped Graphene And Nanoparticles Supported On Graphene, Parichehr Afshani

Theses and Dissertations

The major objective of the research described in this dissertation is the development of new laser vaporization methods for the synthesis of metal and semiconductor nanoparticles, graphene, B- and N-doped graphene, and metal and semiconductor nanoparticles supported on graphene. These methods include the Laser Vaporization Controlled Condensation (LVCC) approach, which has been used in this work for the synthesis of: (1) gold nanoparticles supported on ceria and zirconia nanoparticles for the low temperature oxidation of carbon monoxide, and (2) graphene, boron- and nitrogen-doped graphene, hydrogen-terminated graphene (HTG), metal nanoparticles supported on graphene, and graphene quantum dots. The gold nanoparticles supported …

Size-Based Separation Of Bioparticles Using Planar Nanofluidic Devices, Jie Xuan

Theses and Dissertations

Nanofluidic devices are structures having at least one dimension in the submicron range, which is of the same order of magnitude as the sizes of biomolecules and bioparticles such as proteins and viruses. As a result, size-selective separations are important applications for nanofluidics. Well-defined micro or nano device structures fabricated via micromachining have greatly reduced sample consumption and enabled separations in a parallel fashion, promising significant speed and resolution advantages over conventional size separation techniques, such as gel electrophoresis and size exclusion chromatography. In collaboration with others, I have developed a size separation method using nanofluidic devices consisting of an …

The Synthesis And Structural Characterization Of Metal Oxide Nanoparticles Having Catalytic Applications, Stacey Janel Smith

Theses and Dissertations

Nanotechnology is blossoming into one of the premiere technologies of this century, but the key to its progress lies in developing more efficient nanosynthesis methods. Variations in synthetic technique, however, can cause variations in size, structure, and surface characteristics, thereby altering the physical properties and functionality of the particles. Careful structural characterizations are thus essential for understanding the properties and appropriate applications for particles produced by new synthetic techniques.In this work, a new ‘solvent-deficient’ method is presented for the synthesis of an unprecedentedly wide range of metal oxide nanomaterials including at least one metal oxide from each group in Groups …

Growth Mechanisms Of Complex Organics In The Gas Phase And On Metal Nanoparticles Generated By A Laser Vaporization Process, Abdel Rahman Soliman

Theses and Dissertations

In this dissertation, the ion mobility mass spectrometry technique is used to study the possible mechanisms of formation of polyaromatic hydrocarbons (PAHs) and polyaromatic nitrogen-containing hydrocarbons (PANHs) via the ion-molecule reactions of acetylene neutrals with different aromatic cations, in order to infer the possible mechanisms of formation of PAHs and PANHs in different environments such as interstellar media under different ionizing conditions. Furthermore, this technique is used to probe structures, address the thermochemistry, and measure the kinetics of the product ions originated from these reactions. Reactions of benzene radical cations with acetylene produce styrene and naphthalene-type cations at high temperatures. …

Core-Shell Nanoparticles: Synthesis, Design, And Characterization, Kyler Carroll

Theses and Dissertations

The design of core/shell nanoparticles is of great interest for a wide range of applications. The primary focus of this dissertation is on the design and optimization of two synthetic routes. The first one is an aqueous reduction method using sodium borohydride and sodium citrate. This method was extended to design two types of core/shell nanoparticles, both of which have many applications in bio-sensing, magnetic resonance imaging, and magnetically guided SERS for the identification of environmental threats. The first, Fe/Ag core/shell nanoparticles were designed using a novel one-pot method by varying the AgNO₃ addition time in the system. For …

Dna-Templated Nanomaterials, Hector Alejandro Becerril-Garcia

Theses and Dissertations

Nanomaterials display interesting physical and chemical properties depending on their shape, size and composition. Self assembly is an intriguing route to producing nanomaterials with controllable compositions and morphologies. DNA has been used to guide the self assembly of materials, resulting in: (1) metal nanowires; (2) metal or semiconductor nanorods; (3) carbon nanotubes; and (4) semiconductor, metal or biological nanoparticles. My work expands the range of DNA templated nanomaterials and develops novel ways of using DNA to pattern nanostructures on surfaces. I have performed the first synthesis of silver nanorods on single stranded DNA, an attractive material for localizing DNA coupled …