The synthesis of highly porous organic polymers with predefined porosity has attracted considerable attention due to their potential in a wide range of applications. Porous organic polymers (POPs) offer novel properties such as permanent porosity, adjustable chemical nature, and noteworthy thermal and chemical stability. These remarkable properties of the POPs make them promising candidates for use in gas separation and storage. The emission of carbon dioxide (CO2) from fossil fuel combustion is a major cause of global warming. Finding an efficient separation and/or storage material is essential for creating a cleaner environment. Therefore, the importance of the POPs in the field is undeniable. Along these pursuits, several porous polymers have been synthesized with different specifications. The first class of porous polymers are called Covalent Organic Frameworks (COFs). They possess highly ordered structures with very high surface areas and contain light elements. COFs based on B-O, C-N, and B-N bonds have been reported so far. In particular, COFs based on B-O bond formation are well investigated due to the kinetically labile nature of this bond which is essential for overcoming the crystallization problem of covalent networks. Along this line, triptycene-derived covalent organic framework (TDCOF-5) has been synthesized through a condensation reaction between 1, 4-benzenediboronic acid and hexahydroxytriptycene which leads to the formation of boronate ester linkage. TDCOF-5 has the highest H2 uptake under 1 atm at 77K (1.6%) among all known 2D and 3D COFs derived from B–O bond formation and moderate CO2 uptake (2.1 mmol g-1) with Qst values of 6.6 kJ mol-1 and 21.8 kJ mol-1, respectively. The second class of porous structures discussed herein is diazaborole linked polymers (DBLPs). They are constructed based on B-N bond formation and possess amorphous structures due to the lack of the reversible bond formation processes. At this scope, 2, 3, 6, 7, 14, 15-hexaaminotriptycene (HATT) hexahydrocloride was synthesized and reacted with different boronic acid derivatives to produce three different porous polymers under condensation reaction conditions. DBLP-3, -4 and -5 have very high surface areas; 730, 904, and 986 m2 g-1, and offer high CO2 uptake (158.5, 198, and 171.5 mg g-1) at 1 bar and 273 K, respectively. DBLPs have much higher CO2 uptake capacity when compared to almost all reported B-N and B-O containing porous polymers in the field. In addition to high CO2 capacity, DBLPs showed remarkable CO2/N2 and CO2/CH4 selectivity, when the Henry`s law of initial slope selectivity calculations were applied. In general, DBILPs exhibit high selectivities for CO2/N2 (35-51) and CO2/CH4 (5-6) at 298 K which are comparable to those of most porous polymers.

Iron oxide nanoparticles are highly researched for their use in biomedical applications such as drug delivery, diagnosis, and therapy. The inherent biodegradable and biocompatible nanoparticle properties make them highly advantageous in nanomedicine. The magnetic properties of iron oxide nanoparticles make them promising candidates for magnetic fluid hyperthermia applications. Designing an efficient iron oxide nanoparticle for hyperthermia requires synthetic, surface functionalization, stability, and biological investigations. This research focused on the following three areas: optimizing synthesis conditions for maximum radiofrequency induced magnetic hyperthermia, designing a simple and modifiable surface functionalization method for specific or broad biological stability, and in vitro and in vivo testing of surface functionalized iron oxide nanoparticles in delivering effective hyperthermia or radiotherapy. The benzyl alcohol modified seed growth method of synthesizing iron oxide nanoparticles using iron acetylacetonate as an iron precursor was investigated to identify significant nanoparticle properties that effect radiofrequency induced magnetic hyperthermia. Investigation of this synthesis under atmospheric conditions revealed a combination of thermal decomposition and oxidation-reduction mechanisms that can produce nanoparticles with larger crystallite sizes and decreased size distributions. Nanoparticles were easily surface functionalized with (3-Glycidyloxypropyl)trimethoxysilane (GLYMO) without the need for organic-aqueous phase transfer methods. The epoxy ring on GLYMO facilitated post-modifications via a base catalyzed epoxy ring opening to obtain nanoparticles with different terminal groups. Glycine, serine, γ-aminobutryic acid (ABA), (S)-(-)-4-amino-2-hydroxybutyric acid (SAHBA), ethylenediamine, and tetraethylenepentamine were successful in modifying GLYMO coated-iron oxide nanoparticles to provide colloidal and varying biological stability while also allowing for further conjugation of chemotherapeutics or radiotherapeutics. The colloidal stability of cationic and anionic nanoparticles in several biologically relevant media was studied to address claims of increased cellular uptake for cationic nanoparticles. The surface functionalized iron oxide nanoparticles were investigated to determine effects on cellular uptake and viability. In vitro tests were used to confirm the ability of iron oxide nanoparticles to provide effective hyperthermia treatment. S-2-(4-Aminobenzyl)-1,4,7,10-tetraazacyclododecane tetraacetic acid (DOTA) was coupled to SAHBA and carboxymethylated polyvinyl alcohol surface functionalized iron oxide nanoparticles and radiolabeled with 177Lu. The capability of radiolabeled iron oxide nanoparticles for delivering radiation therapy to a U87MG murine orthotopic xenograft model of glioblastoma was initially investigated.

Activated carbons as emerging classes of porous materials have gained tremendous attention because of their versatile applications such as gas storage/separations sorbents, oxygen reduction reaction (ORR) catalysts and supercapacitor electrodes. This diversity originates from fascinating features such as low-cost, lightweight, thermal, chemical and physical stability as well as adjustable textural properties. More interestingly, sole heteroatom or combinations of various elements can be doped into their framework to modify the surface chemistry. Among all dopants, nitrogen as the most frequently used element, induces basicity and charge delocalization into the carbon network and enhances selective adsorption of CO2. Transformation of a task-specific and single source precursor to heteroatom-doped carbon through a one-step activation process is considered a novel and efficient strategy. With these considerations in mind, we developed multiple series of heteroatom doped porous carbons by using nitrogen containing carbon precursors. Benzimidazole-linked polymers (BILP-5), benzimidazole monomer (BI) and azo-linked polymers (ALP-6) were successfully transformed into heteroatom-doped carbons through chemical activation by potassium hydroxide. Alternative activation by zinc chloride and direct heating was also applied to ALP-6. The controlled activation/carbonization process afforded diverse textural properties, adjustable heteroatom doping levels and remarkable gas sorption properties. Nitrogen isotherms at 77 K revealed that micropores dominate the porous structure of carbons. The highest Brunauer-Emett-Teller (BET) surface area (4171 m2 g-1) and pore volume (2.3 cm3 g-1) were obtained for carbon synthesized by KOH activation of BI at 700 °C. In light of the synergistic effect of basic heteroatoms and fine micropores, all carbons exhibit remarkable gas capture and selectivity. Particularly, BI and BIPL-5 derived carbons feature unprecedented CO2 uptakes of 6.2 mmol g-1 (1 bar) and 2.1 mmol g-1 (0.15 bar) at 298 K, respectively. The ALP-6 derived carbons retained considerable amount of nitrogen dopants (up to 14.4 wt%) after heat treatment owing to the presence of more stable nitrogen-nitrogen bonds compared to nitrogen-carbon bonds in BILP-5 and BI precursors. Subsequently, the highest selectivity of 62 for CO2/N2 and 11 for CO2/CH4 were obtained at 298 K for a carbon prepared by KOH activation of ALP-6 at 500 °C.

The advent of nanoscience and nanotechnology has sparked many research forefronts in the creation of materials with control over size, shape, composition, and surface properties.1,2 However, for most of the applications, nanoscale materials need to be assembled into functional nanostructures that exhibit useful and controllable physical properties. Therefore, numerous efforts on the assembly of nanoparticles (NPs) using organic ligands, polymers and polyelectrolytes have been reported.3,4 However, the interactions between NPs are mediated by intervening ligands, which are detrimental to charge transport and limit the thermal stability. Hence, developing a new method to produce solid state nanostructures with direct NP linkage has become a significant challenge. To avoid the bridging ligands and improve the conductivity of NP based solid state structures, a novel strategy has been developed in which colloidal NPs undergo condensation to wet “jello-like” hydrogel with direct interfacial linkage. Then hydrogels can be dried supercritically to produce aerogels.5 Resultant nanostructures exhibit low densities, large open interconnected pores, and high internal surface areas and are containing entirely of colloidal metal NPs.6 Since noble metal NPs have been widely used in applications such as catalysts, sensors, and novel electrochemical device components, we herein expanded the sol-gel method to noble metal NPs to produce a new class of metal aerogels. In the dissertation, the synthesis of hollow Ag hollow NPs, Au/Ag alloy NPs, and Au/Pt/Ag alloy hollow NPs with tunable sizes and physical properties, and their oxidative-assembly into high-surface-area, mesoporous, self-supported gel framework has been achieved. The gelation kinetics have been controlled by tuning the oxidant/thiolate molar ratio that governs the rate of NP condensation, which in turn determines the morphology, optical transparency, surface area, and porosity of the gel frameworks. These low-density mesoporous nano-architectures displaying optical transparency or opacity, enormously surface area, and interconnected meso-to-macro pore structure are promising candidates for catalytic, electrocatalytic, and SERS-based sensing applications. The SERS activity of Au/Ag alloy aerogels has been studied and significant signal enhancement was achieved. The performance of the Au/Pt/Ag aerogel towards methanol oxidation reaction has been studied via cyclic voltammetry and significant electro-catalytic activity was observed.

Layered perovskites can be classified in three major groups: Dion-Jacobson AA′n-1BnO3n+1, Ruddlesden-Popper A2A′n-1BnO3n+1,and Aurivillius phase (Bi2O2)A′n-1BnO3n+1. (A: Alkali metal, Alkali-earth metal; A′: Lanthanides and Bi; B: Ti, Nb, Ta; n: thickness of slabs). For more than two decades researchers have shown much interest in this series because of their magnetic and electrical properties. Tuning synthesis parameters such as temperature, time, and host structure can be used to direct such properties. Low temperature synthetic methods (topochemical methods) allow the preparation of compounds not accessible by traditional high temperature reactions. This dissertation mainly considers the topochemical methods of ion exchange and reductive and oxidative intercalation to build new low temperature or metastable layered perovskites. The two-dimensional Dion-Jacobson ALaNb2O7 layered perovskites were intercalated reductively to produce A2LaNb2O7 andthen oxidized with water or hydro-chalcogenides (H2Ch, Ch: S, Se) to produce the novel alkali metal hydroxide, (A2OH)LaNb2O7, and alkali metal hydro-chalcogenides, (A2ChH)LaNb2O7, respectively. The synthesis and characterization of these compounds are presented in Chapters 2 and 3. In another set of studies, high temperature ceramic methods lead to the new host APrNb2O7. When this reaction is followed by ion exchange, (CuCl)PrNb2O7 can be prepared. The structural refinement, magnetic properties, and thermal stability of new phases have been studied in Chapter 4. The utility of praseodymium niobates for the formation of other metal oxyhalides was also developed; the series (MX)PrNb2O7 (M: Mn, Fe, Co, Cu and X: F, Cl) were prepared by the ion exchange of LiPrNb2O7 and the obtained phases characterized (Chapter 5). Further, to expand the library of materials and because of interesting properties of lanthanides (Ln: La, Pr, Nd, Sm), lanthanide tantalates have been explored for the preparation of oxyhalides and resulted in the compounds (CuCl)LnTa2O7 (Ln: Pr, Nd) (Chapter 6). Manipulation of Dion-Jacobson layered perovskites are not limited to lanthanides, other hosts with interesting properties have been examined (e.g. ABiNb2O7) (A: alkali metal, CuCl) and their crystal structures characterized along with thermal stability and magnetic response.

In 2013, the worldwide production of renewable electricity accounted for 22.1% of the total energy production with 0.9% coming from solar photovoltaics (PVs). Recently, there has been a growing interest for Cu2ZnSnS4 (CZTS) quaternary semiconductor due to the abundance and low cost of its precursors. Moreover, this chalcopyrite material has an ideal direct band gap around 1.5 eV, high absorption coefficient (α >104 cm-1) and high conductivity, making it suitable for nanostructured and dye-sensitized solar cell (DSSC) applications. Here, CZTS nanoparticles have been synthesized by pulsed laser deposition (PLD) and simultaneously deposited in the interstitial space of ZnO nanowire arrays to form bulk heterojunction 3D nanostructured solar cells. Secondly, vertically oriented CZTS nanoplates have been synthesized by PLD and used as counter electrode in platinum-free dye-sensitized solar cells. These CZTS nanostructures proved to be suitable in achieving workable solar cells, which could significantly cut down the cell cost and provide environmentally friendly photovoltaic devices. Alternately, hybrid organic–inorganic perovskite solar cells have become one of the most attractive photovoltaic technologies with easy solution fabrication and high conversion efficiencies. However, the devices remain unstable under certain processing and environmental conditions. Herein, formamidinium lead tri-halide perovskite (FAPbI3) planar heterojunction solar cells have been fabricated under a controlled environment. The fabrication parameters (precursor concentration, annealing, etc) and the effect of humidity on the structural, optical, and electrical properties of FAPbI3 thin films and devices have been investigated and proved to be critical in the processing of efficient devices. Solar cells with conversion efficiency of 16.6% have been obtained. Furthermore, in-situ techniques such as in-situ (scanning) transmission electron microscopy and in-situ XRD were performed to understand the crystallization and degradation mechanisms of FAPbI3 thin films.The in-situ data were correlated with planar heterojunction FAPbI3 devices efficiency data in order to improve the device fabrication process.

An in situ deposition procedure was developed for the nanopeapod (NPP) formation of NiAu nanoparticles inside preformed acid-exchanged hexaniobate nanoscrolls (HNB). Metal salt precursors of Ni(acac)2 and HAuCl4∙3H2O were reduced in solution under mild synthetic conditions in the presence of the preformed acid-exchanged hexaniobate nanoscrolls. Two of the surfactants used for the formation of the nanoparticles were oleylamine and triphenylphosphine oxide (TTPO). Reaction conditions were studied and modified to produce well-defined NiAu@HNB NPP systems, with monodispersed particles evenly filling and orienting within the nanoscrolls. The synthetic parameters studied were both time and temperature, with the most well-defined peapod systems being those produced from lower temperatures (100°C) and longer reaction times (60 minutes). NiAu@HNB NPPs synthesized under these conditions yielded a narrow size distribution of NiAu nanoparticles, ranging ~ 4 – 10 nm in diameter, evenly filled and oriented within the inner diameter of hexaniobate nanoscrolls (ranging ~2 μm in length).

The ability to encapsulate/insert different kinds of nanoparticles (NPs) in scrolled nanosheets (NSs) may lead to the formation of new nanocomposite materials that yield novel properties. These nanostructures resemble “peapods” that consist of NPs chains (“peas”) located in a hollow space of desired nanoscrolls (“pods”). Depending on different combinations of “peas” and “pods” diverse families of nanopeapods (NPPs) can be synthesized which may exhibit interesting properties not accessible from the individual components. Though there exist various synthetic methods for the formation of NPPs, more development in terms of simplicity, flexibility, and productivity of synthetic approaches are needed so that different classes of NPPs with unique combinations/characteristics of “peas” and “pods” can be synthesized. A simple solvothermal synthesis method for the encapsulation of spherical Fe3O4 NPs by the capture of preformed NPs in scrolled hexaniobate has previously been developed in our group. In the first part of this research, efforts were made to extend the “pod” materials to other inorganic NScs. Vanadate nanoscrolls (NScs) could rapidly (2h) be produced using a simple solvothermal treatment in the presence of V2O5 as vanadium source, and either dodecylamine (DDA) or octadecylamine (ODA) as the structure-directing agent. The synthesis parameters were successfully adjusted to obtain high yields vanadate NScs (~ 20 g of NScs per synthesis) with different average lengths as 383 nm, 816 nm to 3.3 µm. The effects of reaction time on the formation of NScs were also investigated. Further efforts focused on the development of methods for making vanadate NPPs. Here, two novel approaches for the formation of these NPPs have been successfully developed. In the first, solvothermal methods utilizing preformed Ag NPs and vanadate NSs lead to the formation of Ag@vanadate NPPs where NPs could be encapsulated during the scrolling of NSs. High NP loadings were acquired with this approach. In the second method, an insertion strategy was developed where Ag NPs were drawn into the lumen of preformed vanadate NScs upon controlled solvent evaporation. This method was also quite effective, though much lower loadings of NPs were achieved with larger average NP-NP distances. Also noteworthy in the study of vanadate NScs and NPPs is the observation of an uncommon asymmetric scrolling behavior; this was realized for both vanadate NScs and solvothermally synthesized Ag@vanadate NPPs. Novel solvothermal approaches for the effective construction of organic-MoOx hybrid structures and MoOx nanosheets (NSs) have also been developed. These NSs can be controlled so as to exist in different oxidation states as well as in different crystal structures. Layer spacing as a function of organic molecule lengths could also be controlled by changing the type of surfactants located between the NSs. Individual NSs or a few layers of stacked NSs, up to four micrometers in lateral size were successfully prepared upon sonication. The effect of time, temperature, as well as the type of structure-directing agents on the formation and crystal structure of MoOx intercalated compound/NSs were also explored. Lastly, a modified solvothermal method previously used for the encapsulation of spherical Fe3O4 NPs inside hexaniobate NScs was applied for the construction of cubic-CeO2 NPPs. High yield encapsulations of preformed cubic ~5 nm ceria NPs within the lumen of hexaniobate NScs were readily accomplished. Size selective encapsulation and the formation mechanism of cubic-CeO2 NPPs were also studied. Pre-organization and attachment of ceria NPs to the surface/edges of hexaniobate crystals prior to the scrolling process were observed, which is in a good agreement with our previous studies on the formation mechanism of NPPs. Partially filled CeO2@hexaniobate NPPs were further used in the in-situ growth of gold NPs within the empty/hollow space of hexaniobate NScs. This led to the formation of high-quality Au-CeO2@hexaniobate NPPs. We believe that smart combinations of the methods for the formation of NPPs, encapsulation, in-situ growth and insertion, will allow one to acquire other classes of nanocomposite materials composed of different types, shapes, and arrangements of NPs in the hollow spaces of distinct NTs/NScs.

The knowledge on the conformations of amino acids is essential to understand the biochemical behaviors and physical properties of proteins. Comprehensive computational study is focused to understand the conformational landscape of three aromatic amino acids (AAAs): tryptophan, tyrosine, and phenylalanine. Three different density functionals (B3LYP, M06-2X and wB97X-D) were used with two basis sets of 6-31G(d) and 6-31+G(d,p) for geometry optimizations of the conformers of AAAs followed by the vibrational frequencies. The goal was to identify the right choice of density functional theory (DFT) level for conformational analysis of amino acids by comparing the computational data against the available experimental results. Calculated infrared (IR) frequency values indicated that wB97X-D/6-31+G(d,p) level is less favorable than other DFT levels in case of O-H and N-H stretching frequencies for the conformers of AAAs. The C=O stretching frequencies at different computational levels were in good agreement with the experimental results. Interactions of AAAs (tryptophan, tyrosine, and phenylalanine) and two cyclic amino acids (histidine and proline) individually with two finite-sized graphene sheets (C62H20 and C186H36) were explored using M06-2X/6-31G(d) level. Computational investigations of the binding of amino acids with graphene provide knowledge for designing of new graphene-based biological/biocompatible materials. Selected conformers for each amino acid with different orientations on the surface of graphene were examined. The purpose of computational study on graphene-amino acids interactions was to identify the preferred conformer of amino acid to bind on graphene as well as to find the influence of amino acid binding on the band gap of graphene. Different conformers of AAAs generally prefer parallel orientation through π-π interactions to bind with graphene. However, bent orientation is more preferred over parallel to bind on the surface of graphene in case of conformer having relative energy approximately equal to 5 kcal/mol for all three AAAs. Histidine generally exhibits higher binding affinity than proline to form complex with graphene. The binding energies in the aqueous medium were slightly lower than those obtained in the gas phase with some exceptions. The adsorption of amino acids did not affect the band gap of graphene.

Additive manufacturing (AM) for metals is a manufacturing process that has increased a lot in popularity last few years as it has experienced significant improvements since its beginning, both when it comes to accuracy and deposition rates. There are many different AM processes where the energy sources and deposition methods varies. But the common denominator is their layer wise manufacturing process, melting layer on layer. AM has a great design freedom compared to conventional manufacturing, making it possible to design new structures with decreased weight and increased performance.  A drawback is slow manufacturing speeds, making it more expensive. But when it comes to low lot sizes and complex structures AM is very competitive. So, for the aerospace and space industry AM is a good option as manufacturing cost is less of an issue and where saving weight is of great concern, both environmentally and economically.  There are however many topics left to research before additive manufactured titanium can be widely adopted for critical components, such as microstructure and texture development and its correlation to mechanical properties. The aim of this work has been to investigate the microstructure and texture of various AM processes. Microstructural features such as prior β grains, grain boundary α (GB-α), α laths, α colonies have been characterized along with hardness measurements for 5 different AM processes. Some of these AM processes have also been investigated in the SKAT instrument in Dubna, Russia, to obtain their texture. These textures have then been compared with one another and correlated to previous microstructural investigations and mechanical properties. This is important knowledge as the microstructure and the texture sets the basis for the mechanical properties. In case there is a high texture, the material can have anisotropic mechanical behavior, which could be either wanted or unwanted for different applications.   Some the findings are that α phase was found to increase in the prior β grain boundary for the AM processes with low cooling rates, while it was discontinuous and even non-present for the AM processes with high cooling rates. The prior β size are larger for the directed energy deposition (DED) processes than for the powder bed fusion (PBF) processes. Parallel bands were present for the DED process while being non-present for the PBF processes. Concerning the texture, it was found that LMwD had a higher texture than EBM and SLM. Texture inhomogeneity was also found for the LMwD process., where two parts of the same sample was investigated and the material closer to the surface had higher texture.