Mesoporous silica materials containing microporous cavities provided by covalently bound ¦Â-cyclodextrin (CD ICS) were synthesized by co-condensation of a ¦Â-CD functionalized triethoxy silane (CD ICL) with tetraethyl orthosilicate (TEOS) by using neutral amine surfactants as structure directing agents (SDA). CD ICL was prepared by reacting ¦Â-CD with 3-isocyanatopropyltriethoxysilane. IR spectroscopy of CD ICL showed complete disappearance of isocyanato group at 2270 cm-1. 1H NMR results indicate an average of four isocyanate linkers covalently attached to random hydroxyl substituents of each molecule of ¦Â-CD. <p> Nine different CD ICS materials were synthesized using dodecylamine, tetradecylamine or hexadecylamine with ¦Â-CD (2, 4, and 6 mol %) with respect to TEOS. The incorporation of ¦Â-CD within the mesoporous framework was supported by IR, Raman, MALDI TOF MS, solid state 13C NMR CP-MAS and TGA results. Small angle X-ray diffraction results showed a peak at 2¦È ¡Ö 2.20, supporting the presence of an ordered silica mesostructure framework. For materials with same CD loading, the surface area and pore volume doubled as the surfactant from dodecylamine to hexadecylamine. However, as the CD loading increased from 2% to 6%, the surface area decreases by a factor of ~ 1.5. <p>MALDI TOF mass spectrometry showed two peaks at m/z 1157 a.m.u. and 1173 a.m.u. for [¦Â-CD + Na]+ and [¦Â-CD + K]+ respectively due to desorption of ¦Â-CD from the walls of the silica matrix. The 13C NMR CP MAS results showed 13C signals in the region ¦Ä=60-110 ppm due to the nuclei of ¦Â-CD. CD ICS materials were found to be effective as a sorbent in both gas and aqueous phases, respectively. The sorption capacity (mmol/g) of p-nitrophenol increased from 61% to 84% with an increase of CD loading from 2% to 6% and as the alkyl chain length of the SDA increases from dodecylamine to hexadecylamine. The adsorption isotherm of CH3Cl in the gas phase and that of p-nitrophenol in the aqueous phase at ambient temperature adopts a multilayer model of adsorption.

Mesoporous silica materials containing microporous cavities provided by covalently bound ¦Â-cyclodextrin (CD ICS) were synthesized by co-condensation of a ¦Â-CD functionalized triethoxy silane (CD ICL) with tetraethyl orthosilicate (TEOS) by using neutral amine surfactants as structure directing agents (SDA). CD ICL was prepared by reacting ¦Â-CD with 3-isocyanatopropyltriethoxysilane. IR spectroscopy of CD ICL showed complete disappearance of isocyanato group at 2270 cm-1. 1H NMR results indicate an average of four isocyanate linkers covalently attached to random hydroxyl substituents of each molecule of ¦Â-CD. <p> Nine different CD ICS materials were synthesized using dodecylamine, tetradecylamine or hexadecylamine with ¦Â-CD (2, 4, and 6 mol %) with respect to TEOS. The incorporation of ¦Â-CD within the mesoporous framework was supported by IR, Raman, MALDI TOF MS, solid state 13C NMR CP-MAS and TGA results. Small angle X-ray diffraction results showed a peak at 2¦È ¡Ö 2.20, supporting the presence of an ordered silica mesostructure framework. For materials with same CD loading, the surface area and pore volume doubled as the surfactant from dodecylamine to hexadecylamine. However, as the CD loading increased from 2% to 6%, the surface area decreases by a factor of ~ 1.5. <p>MALDI TOF mass spectrometry showed two peaks at m/z 1157 a.m.u. and 1173 a.m.u. for [¦Â-CD + Na]+ and [¦Â-CD + K]+ respectively due to desorption of ¦Â-CD from the walls of the silica matrix. The 13C NMR CP MAS results showed 13C signals in the region ¦Ä=60-110 ppm due to the nuclei of ¦Â-CD. CD ICS materials were found to be effective as a sorbent in both gas and aqueous phases, respectively. The sorption capacity (mmol/g) of p-nitrophenol increased from 61% to 84% with an increase of CD loading from 2% to 6% and as the alkyl chain length of the SDA increases from dodecylamine to hexadecylamine. The adsorption isotherm of CH3Cl in the gas phase and that of p-nitrophenol in the aqueous phase at ambient temperature adopts a multilayer model of adsorption.

ABC type amphiphilic triblock copolymers, polyethylene-b-poly(ethylene oxide)-b-poly (£`-caprolactone) (PE-b-PEO-b-PCL), were synthesized through ring-opening polymerization. We have successfully synthesized hierarchical mesoporous silicas using a simple evaporation-induced self-assembly (EISA) strategy. Two blocks of hydrophobic segment (PE and PCL) in the triblock copolymer (PE-b-PEO-b-PCL) involved in two-type mesepores after calcinations. We recognized the PE segment attributed to face centered cubic (f. c. c.) morphology (spherical pore) and the PCL segment attributed to tetragonal cylinder structure (cylinder pore) by small angle X-ray scattering (SAXS), transmission electron microscopy (TEM) and specific surface area & pore size distribution analyzer (BET), respectively. We also investigated the effect on pore size and morphology with changing the molecular weight of PCL and the ratios of TEOS/template/HCl. We also synthesized the mesoporous phenolic resin by triblock copolymer poly(ethylene oxide)-b-poly(£`-caprolactone)-b-poly(L-lactide) (PEO-b-PCL-b-PLLA). After curing and calcinations, we also explored the morphology and pore size distribution of mesoporous phenolic by SAXS, TEM, BET. Because of the sequence of hydrophobic segment PCL and PLLA lay in the same side, so we could only observe hexagonal cylinder structure and one pore size.

Over the past few decades there has been great interest in exploring alternatives to conventional separation methods due to their high cost and energy requirements. Membranes offer a potentially attractive alternative as they potentially address both of these points. The overarching theme of this dissertation is to design nanocomposite membranes for processes where existing separation schemes are inadequate. This dissertation focuses on three challenges: 1) designing organic-inorganic hybrid membranes for reverse-selective removal of alkanes from light gases, 2) defect-free inorganic nanocomposite membranes that have uniform pores, and 3) nanocomposite membranes for minimizing protein fouling in microfiltration applications. Reverse-selective gas separations that preferentially permeate larger/heavier molecular species based on their greater solubility have attracted considerable recent attention due to both economic and environmental concerns. In this study, dendrimer-ceramic hybrid membranes showed exceptionally high propane/nitrogen selectivities. This result was ascribed to the presence of stable residual solvent that affects the solubility of hydrocarbon species. Mesoporous silica-ceramic nanocomposite membranes have been fabricated to provide defectless mesoporous membranes. As mesoporous silica is iteratively synthesized in the ceramic macropores, the coating method and the surfactant removal step significantly affected permeance and selectivity. It was also shown that support layers can cause a lower selectivity than Knudsen limit. Membrane fouling which results from deposition and nonspecific adsorption of proteins on the membrane surface is irreversible in nature, and results in a significant decrease in the membrane performance. To address this problem, two approaches were explored: 1) control of the surface chemistry tethering alumina membranes with organic components and 2) development of a novel photocatalytic membrane that exhibits hydrophilicity and can be easily regenerated. Both approaches can offer a viable route to the synthesis of attractive membranes, in that 1) the density of protein-resistant organic groups such as PEG is controllable by changing scaffolds or synthesis conditions and 2) the photocatalytic nanocomposite membranes can open the way for a new regeneration method that is environmentally benign.

Nanoporous materials have attracted tremendous interest, investment and effort in research and development due to their potential applications in various areas such as membranes, catalysis, sensors, delivery, and micro devices. Controlling a nanoporous material’s microstructure is of great interest due to the strong influence on efficiency and performance. For particles, microstructure refers to particle size, shape, surface morphology, and composition. When discussing thin films, microstructure includes film thickness, crystal orientation and grain boundaries. In this respect, we focus to develop novel methods for the synthesis and characterization of nanoporous materials and their films, which are capable of controlling the microstructure of material. This dissertation is composed of two main sections and each explores the fabrication of a different nanoporous material: 1) A simple fabrication method for producing oriented MFI zeolite membranes with controlled thickness, orientation, and grain boundary; 2) A microfluidic synthesis of ordered mesoporous silica particles with controllable size, shape, surface morphology, and composition. The first section of this dissertation demonstrates a simple and commercially viable method termed the micro-tiles-and-mortar method to make continuous b-oriented MFI membranes with controlled membrane microstructure. This simple method allows for control of the thickness of the membrane by using plate-like seed crystals with different thicknesses along the b-axis (0.5 μm to 2.0 μm), as well as to manipulate the density and structure of grain boundaries. Microstructural effects of silicalite-1 membranes on the gas separation are investigated by measuring the permeation and separation for xylene isomers. In the second section of this dissertation, a new synthesis method for the ordered mesoporous silica particles with controllable microstructure is demonstrated. This novel method combines a microfluidic emulsification technique and nonaqueous inorganic synthesis with a diffusion-induced self-assembly (DISA). The systematic control of the particle microstructure such as size, shape, and surface morphology is shown by adjusting microfluidic conditions.

Template synthesis and mesostructural characterization of ordered mesoporous silica, titania and carbon materials have been systematically investigated in this study. In order to obtain a better understanding of the template-precursor relationship, there are two templates adopted in this research. One is the ¡§liquid crystal template (LCT)¡¨, composed of surfactants via self-assembly pathway; the other is the ¡§ordered silica spheres template¡¨, composed of monodispersed SiO2 spheres (~40 nm) via gravity sedimentation. This work was carried out in four related directions: (1) Synthesis and functionalization of ordered mesoporous silicate (MCM-41 and MCM-48) via cationic surfactant template; (2) Using anionic surfactant template-assisted via urea treatment to control the morphology of the TiO2; (3) Synthesis of ordered mesoporous anatase TiO2 via cationic surfactant template; (4) Synthesis of ordered mesoporous carbon from mesophase pitch solution via silica spheres template. Mesoporous silica materials MCM-41 and MCM-48 have been synthesized and identified. The MCM-41 has a hexagonal phase (p6m) with surface area of 1006.90 m2/g and pore size of 37.65 &#x00C5;, The MCM-48 has cubic phase ( ) with surface area of 1093.34 m2/g and pore size of 29.20 &#x00C5;. The calcined MCM-41was rehydrated by heating in water and functionalized with 3-amino propyltrimethoxysilane; this functionalized mesoporous silica is targeted as a template of metal oxides, such as TiO2. appears the same tendency of parent MCM-41 in the N2 sorption isotherm measurements. Nanocrystalline TiO2 rods and hollow-tubes with an engraved pattern on the surface have been prepared by the anionic template-assisted sol-gel synthesis via urea treatment and under hydrothermal condition. X-ray diffractometry (XRD) results indicate that these nanocrystallines consist predominantly of anatase TiO2, with minor amounts of rutile and brookite. The crystallographic facetting found from SEM and TEM further reveals the polymorphic nature of the nanocrystalline TiO2 thus prepared. A ¡§reverse micelle¡¨ formation mechanism taking into account the hydrothermal temperature, the pH effect of the sol-gel system, the isoelectric point, the formation of micelles, and the electrostatic interaction between the anionic surfactant and the growing TiO2 particulates is proposed to illustrate the competition between the physical micelle assembly of the ionic surfactants and the chemical hydrolysis and condensation reactions of the Ti precursors. Ordered mesoporous TiO2 materials with an anatase framework have been synthesized by using a cationic surfactant template and soluble peroxytitanates as Ti precursor through an S+I− self-assembly pathway. The low-angle X-ray diffraction (XRD) pattern of the as-prepared mesoporous TiO2 materials indicates a hexagonal mesostructure. XRD and TEM results and N2 sorption isotherms measurements indicate the calcined mesoporous TiO2 possesses an anatase crystalline framework having a maximum pore size of 6.9 nm and a maximum BET specific surface area of 284 m2/g. This ordered mesoporous TiO2 also demonstrates a high photocatalytic activity for degradation of methylene blue under ultraviolet irradiation. Under a lower carbonization temperature and with a mesophase pitch solution as the carbon precursor, ordered mesoporous carbon thick films with 35-nm pore size have been synthesized using SiO2 spheres as the template. The pore size of the mesoporous carbon thus fabricated was the smallest one ever reported using silica templates. SEM and TEM patterns show a discernible morphology of an ordered cubic close-packing of the mesopores interconnected via holes of 6 nm in diameter. From this study, the template synthesis has been proven to be an effective method to fabricate mesoporous silica, polymorphic titania, ordered mesoporous TiO2, and ordered mesoporous carbon materials. Further utilization of this template synthesis is expected to offer a variety of porous networks with a wide range of pore sizes, well-defined morphologies on controllable length scales, and various chemical functionalities to match the needs of different applications.

New approaches through grafting initiators onto the surface of inner-wall of mesoporous silica to synthesize polymer inside the nano-channels to obtain mesoporous silica/polymer nanocomposites were developed and investigated. Using the newly developed approach, PMMA was successfully synthesized through free radical polymerization and nylon 6 though in situ anionic ring-opening polymerization inside the nano-channels. The spherical mesoporous silica/PMMA composites we obtained showed a higher degradation temperature and narrower degradation range than pure commercially available PMMA. Spherical PMMA capsules were obtained after the silica network was dissolved with hydrofluoric acid, these pure PMMA spheres had the same thermal properties and morphology as they had with in the composites. The BMS/nylon 6 nanocomposites were spheres with the same diameter as pure BMS. About 50 wt% of the composites was newly synthesized nylon 6. The synthesized nylon 6 was proven to contain both α-form crystallite and γ-form crystallites with covalent bonds with the surface of silica inside the nano-channels.

The major goals of this thesis were to (1) design and synthesize a supported catalyst with well-defined monodisperse palladium nanoparticles evenly distributed throughout an inorganic oxide substrate with tunable porosity characteristics, (2) demonstrate the catalytic activity of this material in the decarboxylation of long chain fatty acids and their derivatives to make diesel-length hydrocarbons, (3) elucidate the deactivation mechanism of supported palladium catalysts under decarboxylation conditions via post mortem catalyst characterization and develop a regeneration methodology thereupon, and (4) apply this catalytic system to a real low-value biofeedstock. In an effort to maximize loading and minimize mass transfer limitations, mesoporous silica MCF was synthesized as catalyst support. Functionalization with various silane ligands facilitated even distribution of palladium precursor salts throughout the catalyst particle, and, after reduction, monodisperse palladium nanoparticles approximately 2 nm in diameter. The Pd-MCF catalyst showed high one-time activity in the decarboxylation of fatty acids to hydrocarbons in dodecane at 300 °C. Subsequent reactions were performed on acid derivatives to elucidate a decarboxylation reaction pathway. The catalyst experienced severe deactivation after only one use and substantial effort was put into elucidating the nature of this deactivation via post mortem catalyst characterization. The deactivation was found not to be caused by nanoparticle sintering, agglomeration or ripening, but instead by organic deposition, mainly of reactant acid. A regeneration methodology was developed and subsequent catalyst reuse exhibited high activity. Finally, the Pd-MCF catalyst was applied to a wastewater-derived brown grease from a poultry rendering facility, in an unpolished and polished form. The latter was successfully decarboxylated to diesel-length hydrocarbons with high conversion and selectivity.

The use of novel hyperbranched aminosilica (HAS) materials created through the ring-opening polymerization of aziridine from mesoporous silica supports was proposed for the adsorption of CO2 from dilute sources. The limits of the adsorptive performance of these adsorbents were investigated via the preparation of sets of materials with a range of aminopolymer loadings on several different silica supports with different pore space characteristics. Relationships were determined between the materials' amine loadings and the CO2 adsorption performance. Adsorbents with substantial remaining pore volume displayed universal adsorption kinetics when normalized by amine loading. However, materials with blocked pores displayed substantially slower adsorption kinetics due to hindered mass transfer. In both humid and dry conditions, the HAS adsorbent was found to have a surprisingly large CO2 capacity in light of the 250-fold reduction in CO2 partial pressure from 10% CO2 (flue gas application) to 400 ppm CO2 (air capture application). Finally, a new series of linear aminosilicas was created through the reaction of existing aminosilicas with N-protected-aziridines. Specifically, reaction of aminosilane-functionalized silicas with N-methylaziridine resulted in the linear growth of methylaminoethyl groups, effectively increasing the amine loading of the adsorbent by a stoichiometric amount of an additional amine per attached silane.

Poor aqueous solubility is one of the greatest barriers for new drug candidates to enter toxicology studies, let alone clinical trials. This thesis focuses on contributing to solving this problem, evaluating the oral toxicity of mesoporous silica particles, and enhancing the apparent solubility and bioavailability of active pharmaceutical ingredients in vitro and in vivo using mesoporous silica particles. Toxicological studies in rats showed that two types of mesoporous silica particles given by oral administration were well tolerated without showing clinical signs of toxicity. Solubility enhancement, including in vivo bioavailability and in vitro intracellular activity, has been evaluated for selected drug compounds. Mesoporous silica was shown to effectively increase drug solubility by stabilizing the amorphous state of APIs, such as itraconazole (anti-fungal), dasatinib (anti-cancer), atazanavir (anti-HIV) and PA-824 (anti-tuberculosis). Itraconazole was successfully loaded into a variety of porous silica materials showing a distinct improvement in the dissolution properties in comparison to non-porous silica materials (and the free drug). Microporosity in SBA-15 particles has advantages in stabilizing the supersaturation state of dasatinib. Small pore sizes show better confinement of atazanavir, contributing to a higher dissolution of the drug compound. In the in vivo animal studies, NFM-1 loaded with atazanavir shows a four-fold increase in bioavailability compared to free crystalline atazanavir. PA-824 has a higher dissolution rate and solubility after loading into AMS-6 mesoporous particles. The loaded particles show similar antibacterial activity as the free PA-824. This thesis aims at highlighting some of the important factors enabling the selection of adequate mesoporous structures to enhance the pharmacokinetic profile of poorly water-soluble compounds, and preparing the scientific framework for uncovering the effects of drug confinement within mesopores of varying structural properties. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Submitted. Paper 3: Submitted. Paper 5: Submitted.</p>