The phase behaviors and microstructures of various realistic and model mixtures of macro and micro molecules, such as polyolefin solutions and nanoparticle block copolymer composites, have been accurately predicted by the application of Statistical Associating Fluid Theory (SAFT) based approaches through various extensions that improve both the physical description of molecular interactions and efficiency of computations. The extensions are presented in a generic sense that is applicable to other studies. These rigorously derived theories have been demonstrated to capture material structure-property relationships and can be applied broadly to other fields including biology, medicine and energy industry. On the phenomenogical scale, the novel SAFT-Dimer equation of state has been extended to study the liquid-liquid phase boundary (cloud point) in polyolefin solutions. A simplified model of the polyolefin molecules has been followed and the effect of various parameters, such as temperature, molecular weight, solvent quality and comonomer content, on the phase behavior has been successfully captured by the theoretical model through comparison with experimental measurements. The presented approach requires less parameters than previous methods and is of critical value to the industrial productions of polymers, especially polyolefins with long branches. On the molecular scale, the interfacial SAFT (iSAFT) Density Functional Theory (DFT) has been extended to include a dispersion free energy functional that explicitly accounts for molecular correlations. The Order-Disorder Transition (ODT) between lamellar and disordered phase has then been investigated for pure block copolymer and copolymer nanocomposite systems. The extension has been shown to dramatically improve the ODT predictions of iSAFT as well as the self assembled microstructures in nanocomposites over previous DFT calculations, in comparison to coarse grained molecular simulations. The behavior of the equilibrium spacing of ordered structures is also examined against the variation of copolymer size and interactions. An efficient numerical scheme, Fast Fourier Transform (FFT), has been implemented and shown to drastically increase the computation efficiency. The theory has then been extended to study block copolymer morphologies with density variations in multiple dimensions. Comprehensive phase diagrams including lamellar, cylindrical and disordered phases have been obtained for copolymer nanocomposites for the first time using a single framework molecular theory. In addition, the nanoparticle induced morphological transition between cylindrical and lamellar phase has been studied using a pseudo arc-length continuation method. Transition evolution is tracked and metastable morphologies are examined and compared with existing experimental reports and theoretical calculations. With these extensions, iSAFT offers a powerful prediction tool that closely relates molecular structure to thermophysical properties and provides an efficient alternative to screen parameter space for specified material properties.

Studies various nanostructured materials have gained considerable interest within the past several decades. This novel class of materials has opened up a new realm of possibilities, both for the fundamental comprehension of matter, but also for innovative applications. The size-dependent effect observed for these systems often lies in their interaction with the surrounding environment and understanding such interactions is the pivotal point for the investigations undertaken in this thesis. Three families of nanoparticles are analyzed: semiconductor quantum dots, metallic silver nanoparticles and rare-earth oxide nanomaterials. The radical scavenging ability of cerium oxide nanoparticles (CeO2) is quite controversial since they have been labeled as both oxidizing and antioxidant species for biological systems. Here, both aqueous and organic stabilized nanoparticles are examined in straightforward systems containing only one reactive oxygen species to ensure a controlled release. The apparent absence of their direct radical scavenging ability is demonstrated despite the ease at which CeO2 nanoparticles generate stable surface Ce3+ clusters, which is used to explain the redox activity of these nanomaterials. On the contrary, CeO2 nanoparticles are shown to have an indirect scavenging effect in Fenton reactions by annihilating the reactivity of Fe2+ salts. Cadmium selenide quantum dots (CdSe QD) constitute another highly appealing family of nanocolloids in part due to their tunable, size-dependent luminescence across the visible spectrum. The effect of elemental sulfur treatment is investigated to overcome one of the main drawbacks of CdSe QD: low fluorescence quantum yield. Herein, we report a constant and reproducible quantum yield of 15%. The effect of sulfur surface treatment is also assessed following the growth of a silica shell, as well as the response towards a solution quencher (4-amino-TEMPO). The sulfur treated QD is also tested for interaction with pyronin Y, a xanthene dye that offers potential energy and electron transfer applications with the QD. Interaction with the dye molecule is compared to results obtained with untreated quantum dots, as well as CdSe/ZnS core shell examples. In another chapter of this thesis, the catalytic potential of silver nanoparticles is addressed for the grafting of polyhydrosiloxane polymer chains with various alkoxy groups. A simple one-pot synthesis is presented with silver salts and the polymer. the latter serves as a mild reducing agent and a stabilizing ligand, once silver nanoparticles are formed in-situ. We evaluate the conversion of silane into silyl ethers groups with the addition of several alcohols, whether primary, secondary or tertiary, and report the yields of grafting under the mildest conditions: room temperature, under air and atmospheric pressure.

This research work involves multifunctional magnetically targeted drug delivery microspheres for treatment against breast cancer. A combination therapy approach was followed by encapsulating two chemotherapeutics, 5-Fluorouracil (5-Fu) and cyclophosphamide in poly(D, L-lactide-co-glycolide) (PLGA) microspheres. Magnetite nanoparticles and albumin were also incorporated in the microspheres to achieve targeted treatment. The microspheres were fabricated using oil-in-oil emulsion/solvent evaporation technique. Albumin is attracted to cancer cells and thus it is likely to draw the microspheres towards tumor cells. On application of magnetic field near tumor site, magnetites in the microspheres are likely to guide them to the region of magnetic field. This will allow release of drugs from microspheres in the cancer cells. Also the burst release of drugs and then slow release due to diffusion in the cancer cells lead to effective treatment and also limit excessive spreading of drugs in other regions of the body. Release rate study was carried out using high performance liquid chromatography (HPLC). Invitro and in-vivo study was carried out to check the efficacy of treatment. / Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering.

Studies various nanostructured materials have gained considerable interest within the past several decades. This novel class of materials has opened up a new realm of possibilities, both for the fundamental comprehension of matter, but also for innovative applications. The size-dependent effect observed for these systems often lies in their interaction with the surrounding environment and understanding such interactions is the pivotal point for the investigations undertaken in this thesis. Three families of nanoparticles are analyzed: semiconductor quantum dots, metallic silver nanoparticles and rare-earth oxide nanomaterials. The radical scavenging ability of cerium oxide nanoparticles (CeO2) is quite controversial since they have been labeled as both oxidizing and antioxidant species for biological systems. Here, both aqueous and organic stabilized nanoparticles are examined in straightforward systems containing only one reactive oxygen species to ensure a controlled release. The apparent absence of their direct radical scavenging ability is demonstrated despite the ease at which CeO2 nanoparticles generate stable surface Ce3+ clusters, which is used to explain the redox activity of these nanomaterials. On the contrary, CeO2 nanoparticles are shown to have an indirect scavenging effect in Fenton reactions by annihilating the reactivity of Fe2+ salts. Cadmium selenide quantum dots (CdSe QD) constitute another highly appealing family of nanocolloids in part due to their tunable, size-dependent luminescence across the visible spectrum. The effect of elemental sulfur treatment is investigated to overcome one of the main drawbacks of CdSe QD: low fluorescence quantum yield. Herein, we report a constant and reproducible quantum yield of 15%. The effect of sulfur surface treatment is also assessed following the growth of a silica shell, as well as the response towards a solution quencher (4-amino-TEMPO). The sulfur treated QD is also tested for interaction with pyronin Y, a xanthene dye that offers potential energy and electron transfer applications with the QD. Interaction with the dye molecule is compared to results obtained with untreated quantum dots, as well as CdSe/ZnS core shell examples. In another chapter of this thesis, the catalytic potential of silver nanoparticles is addressed for the grafting of polyhydrosiloxane polymer chains with various alkoxy groups. A simple one-pot synthesis is presented with silver salts and the polymer. the latter serves as a mild reducing agent and a stabilizing ligand, once silver nanoparticles are formed in-situ. We evaluate the conversion of silane into silyl ethers groups with the addition of several alcohols, whether primary, secondary or tertiary, and report the yields of grafting under the mildest conditions: room temperature, under air and atmospheric pressure.

Chemotherapy regimens, one of the most common cancer treatments, are often dictated by dose-limiting toxicities. Also, the largest hurdle for translating novel biological therapies such as siRNA into the clinic is lack of an efficient delivery mechanism to get the therapeutic into malignant cells. Both of these situations would benefit from a minimally-invasive controlled release system that only delivers a therapeutic to the site of malignant tissue. This thesis presents work towards the creation of such a delivery platform using two novel material components: a thermally responsive poly[N-isopropylacrylamide-co-acrylamide] (NIPAAm-co-AAm) hydrogel and gold-silica nanoshells. Thermally responsive hydrogels undergo a physical property transition at their lower critical solution temperature (LCST). When transitioning from below to above the LCST, the hydrogel material expels large amounts of water and absorbed molecules. This phase change can be optically triggered by embedded gold-silica nanoshells, which rapidly transfer near-infrared (NIR) light energy into heat energy due to the surface plasmon resonance phenomena. When this material is loaded with absorbed drug molecules, drug release can be externally triggered by exposure to an NIR laser. Initial characterization of this material was accomplished using bulk hydrogel-nanoshell composites. Poly(NIPAAm-co-AAm)-nanoshell composites were synthesized via free radical polymerization. The LCST of the poly(NIPAAm-co-AAm) hydrogels was determined to be from 39-45 deg C, or slightly above physiologic temperature. The material was swollen in a drug solution of either doxorubicin (a common chemotherapeutic) or a 21bp dsDNA olgio (a model molecule for siRNA). Composites were then exposed to an 808 nm laser, which was found to trigger release of the therapeutics from the composite material. Further work has been done in translating this composite material to nano-scale sized particles, such that it could be injected intravenously, passively accumulate in tumor tissue, and be externally triggered to release therapeutics by exposure to an NIR laser. Sub-micron composite particles were synthesized using dissolvable gelatin templates with 500 nm wells. Analysis by transmission electron microscopy (TEM) indicates that these particles consist of gold nanoshells surrounded by a hydrogel coating. Dynamic light scattering (DLS) measurements were used to show that these particles display the same thermal properties as seen in the bulk material: collapsing in response to increased temperatures or NIR light exposure. Ultimately, the work in this thesis advances the development of a minimally-invasive, optically-triggered drug delivery platform.

Nanocatalysis, catalysis using particles on the nanoscale, is an emerging field that has tremendous potential. Nanoparticles have different properties than bulk material and can be used in different roles. Macro sized precious metals, for example, are inert, but nanoparticles of them are becoming more widely used as catalysts. Understanding the manner in which these particles work is vital to improving their efficacy. This thesis focuses on two aspects of nanocatalysis. Chapter 1 begins with a brief introduction into nanotechnology and some of the areas in which nanoparticles are different than bulk particles. It then proceeds into an overview of catalysis and nanocatalysis more specifically. Focus is brought to the definitions of the different types of catalysis and how those definitions differ when applied to nanoparticles. Chapter 2 is in finding an inert support structure to more easily assist in recycling the nanoparticles. Polystyrene microspheres were studied and found to prevent platinum nanoparticles from aggregating in solution and possibly aid in recycling of the nanoparticles. These nanoparticles were used in catalysis, aiding in the reduction of 4-nitrophenol in the presence of sodium borohydride. While the rate decreased by a factor of ~ 7 when using the polystyrene, the activation energy of the reaction was unaltered, thus confirming the inactivity of the polystyrene in the reaction. In Chapter 3, nanocatalysis was studied by examining bimetallic hollow nanoparticles with specific attention to the effect of altering the ratios of the two metals. Ten different bimetallic nanocages were tested in an electron transfer reaction between hexacyanoferrate and thiosulfate. Five PtAg nanocages and five PdAg with varying metal ratios were prepared and studied. It was found that while silver cubes immediately precipitate out of solution when combined with thiosulfate, a small amount of either platinum or palladium allows the particles to remain in solution and function as a substantially more effective catalyst. However, as additional Pt was added the activation energy increased. To obtain a better understanding of the catalysis using bimetallic cages, the evolution of these cages was studied as the 2nd metal was added. Initially the particle edge length increased and then slowly decreased back to the size of the template cubes. The increase in edge length suggests of addition of material to the nanoparticles. This indicated the 2nd metal is on the outside of the cage, which was confirmed using UV-Vis spectroscopy and EDS mapping. By understanding how these bimetallic particles evolve, we may be able to manipulate these synthetic methods to more precisely design nanoparticles for catalysis.

Las células biológicas, bloques elementales de construcción de la materia viva, son presentadas en grandes cantidades en nuestro planeta, y son extremadamente importantes para nosotros, porque todos estamos hechos de ellos. Un componente esencial de cada célula es la membrana celular, protegiendo las células del medio ambiente y también controlando el transporte de los productos químicos entre el interior y el exterior de la célula. Cuando un extraño nano-objeto se aproxima a la membrana celular, las preguntas importantes sobre su destino surgirán de manera natural. ¿Será el nano-objeto capaz de atravesar la membrana, o la membrana lo parará? ¿Si la nano-objeto dañará seriamente los mecanismos de membrana, provocando el muerte de la célula, o no? Alguien puede imaginar numerosas aplicaciones prácticas de las interacciones específicas posibles entre un nano-objeto y la membrana. Pueden ser utilizadas, por ejemplo, para entregar una medicina necesaria dentro de una célula enferma, o para eliminar las células dañinas específicas por la destrucción de sus membranas o por la supresión de su correcto funcionamiento. Las preguntas mencionadas anteriormente son difíciles de responder en la actualidad, tanto por los métodos experimentales como por los métodos teóricos. La mayor dificultad es la compleja estructura de la membrana celular, que consiste de una bicapa lipídica, con numerosas proteínas integradas en él y ancladas a ella. La base de lípidos de la membrana está formada por una mezcla de fosfolípidos, glucolípidos, colesterol, y los fosfolípidos son el principal compuesto de la bicapa. Así, una bicapa de fosfolípidos puros puede ser considerada como un modelo de una membrana de la célula real, tanto en estudios experimentales como en unos teóricos. Se puede utilizar para estimar las propiedades mecánicas de la membrana biológica, su permeabilidad para diferentes productos químicos y nano-objetos, para estudiar su interacción con las proteínas individuales. El número de los métodos experimentales se aplican con éxito para / Biological cells, elementary building blocks of the live matter, are presented in large amounts on our planet, and they are extremely important for us, because all we are made of them. An essential component of every cell is the cell membrane, protecting the cell from the environment and also controlling the transport of chemicals between the interior and exterior of the cell. When an extraneous nano-object approaches the cell membrane, important questions about their destiny arise naturally. Will be the nano-object able to pass through the membrane, or will the membrane stop it? Will the nano-object severely damage the membrane machinery, causing the cell death, or not? One can image numerous practical applications of specific interactions possible between a nano-object and the membrane. They may be used, for example, to deliver a necessary medicine inside a deceased cell, or to kill some specific harmful cells by destruction of their membranes or by suppression of their proper functioning. The questions outlined above are hard to answer at the present day, both using experimental or theoretical methods. The major difficulty is the complex structure of the cell membrane, consisting of lipid bilayer, with numerous proteins embed into it and anchored to it. The lipid basement of the membrane is formed by mixture of phospholipids, glycolipids, cholesterol, and the phospholipids are the major compound of the bilayer. Thus a pure phospholipid bilayer can be considered as a model of a real cell membrane both in experimental and theoretical studies. It can be used to estimate mechanical properties of the biological membrane, its permeability for different chemicals and nano-objects, to study its interaction with single proteins.

En esta tesis se ha estudia la luminiscencia y la emisión anti-stokes visible por excitación infrarroja a 980 nm, en iones lantánidos embebidos en nanoestructuras de Lu2O3 y KLu(WO4)2, en los cuales los iones lantánidos muestran interesantes propiedades ópticas. Se han producido tres tipos de nanoestructuras con alta cristalinidad a través del método Pechini modificado y síntesis hidrotermal. Se han descrito los mecanismos de fotoluminiscencia, catodoluminiscencia y eficiencia cuántica, en base a las especies adsorbidas en la superficie y la potencia de excitación. Se han sintetizado nanobarras y partículas núcleo-capa que puede ser utilizadas como bloques de construcción de estructuras más complejas en aplicaciones fotónicas. Se ha logrado la generación de luz blanca en nanocristales de (Tm,Ho,Yb)KLu(WO4)2. Estas nanopartículas pueden formar parte de estructuras más complejas en dispositivos emisores de luz o como indicadores para visualización biológica de células. / Nowadays especially attention has been given to materials capable of generating visible light by conversion of near infrared photons (upconversion) for save-energy technologies and reduction of photo-degradation caused by UV high energy photons. Nanoparticles using optically active Ln3+ have shown great potential for use as upconverting luminescent materials in bio-analysis applications, counterfeit fighting and back-lighting. However materials with nanometer dimensions may affect the luminescence dynamics of the Ln3+ ion modifying the emission lifetime, quantum yield, and concentration quenching. This thesis discusses the synthesis and upconversion emission of lanthanide doped nanostructures with Lu2O3 and KLu(WO4)2 as host because they posses high chemical stability; they offer favorable incorporation of Ln3+ ions and high absorption and emission cross sections. Er3+, Ho3+ and Tm3+ are used as emitting ions and Yb3+ as sensitizer. Luminescence dynamics of these ions into these nanostructures and the possibility of white light emission in KLuW nanocrystals are discussed.

Immiscible dispersions of oil and water are encountered in many industries such as food, pharmaceuticals, and petroleum. Phase inversion is a key phenomenon that takes place in such systems whereby the dispersed phase and the continuous phase invert spontaneously. Stabilizers such as surfactants or solid nanoparticles have been used in the past to improve the stability of emulsions. However, the combined effects of surfactants and nanoparticles on phase inversion and stability of oil and water emulsions have not been studied. This study investigates the synergistic effects of silica nanoparticles (of varying hydrophobicities) and non-ionic surfactant on phase inversion of water-in-oil emulsion to oil-in-water emulsion. The effect of oil viscosity on phase inversion phenomenon is also studied. Stabilizers were initially dispersed in the oil phase with the help of a homogenizer. The water concentration of the system was gradually increased while maintaining the mixing. Online conductivity measurements were carried out to obtain the phase inversion point. Experimental results on the effects of pure stabilizers (either silica nanoparticles or surfactant) and mixed stabilizers (combined silica nanoparticles and surfactant) on phase inversion of emulsions are presented. The stability of these emulsions is also investigated. From the results obtained in this study it is clear that catastrophic phase inversion phenomenon and stability of water-in-oil emulsions can be controlled with the help of different stabilizers. In order to extend the critical dispersed phase volume fraction at which phase inversion occurs surfactant type stabilizer was found to be more effective than solid nanoparticles. On the other hand, emulsion stability was mainly dominated by solid nanoparticles. The hybrid of the two stabilizers and its effect on phase inversion and stability are discussed in the thesis.

Immiscible dispersions of oil and water are encountered in many industries such as food, pharmaceuticals, and petroleum. Phase inversion is a key phenomenon that takes place in such systems whereby the dispersed phase and the continuous phase invert spontaneously. Stabilizers such as surfactants or solid nanoparticles have been used in the past to improve the stability of emulsions. However, the combined effects of surfactants and nanoparticles on phase inversion and stability of oil and water emulsions have not been studied. This study investigates the synergistic effects of silica nanoparticles (of varying hydrophobicities) and non-ionic surfactant on phase inversion of water-in-oil emulsion to oil-in-water emulsion. The effect of oil viscosity on phase inversion phenomenon is also studied. Stabilizers were initially dispersed in the oil phase with the help of a homogenizer. The water concentration of the system was gradually increased while maintaining the mixing. Online conductivity measurements were carried out to obtain the phase inversion point. Experimental results on the effects of pure stabilizers (either silica nanoparticles or surfactant) and mixed stabilizers (combined silica nanoparticles and surfactant) on phase inversion of emulsions are presented. The stability of these emulsions is also investigated. From the results obtained in this study it is clear that catastrophic phase inversion phenomenon and stability of water-in-oil emulsions can be controlled with the help of different stabilizers. In order to extend the critical dispersed phase volume fraction at which phase inversion occurs surfactant type stabilizer was found to be more effective than solid nanoparticles. On the other hand, emulsion stability was mainly dominated by solid nanoparticles. The hybrid of the two stabilizers and its effect on phase inversion and stability are discussed in the thesis.