In this thesis we synthesize two organic materials, one is discotic liquid crystal Acid-6, and the other is novel discotic liquid crystal polymer DLC-PAM. After demonstrating the molecular structures of Acid-6 and DLC-PAM by FT-MS, 1H-NMR and FT-IR, we use the two materials as photo-sensitized dyes for dye-sensitized solar cells(DSSCs) and manufacture two kinds of cells. We use polyacrylamide(PAM) as main chain of the novel discotic liquid crystal polymer DLC-PAM and graft the discotic liquid crystal monomer Acid-6 onto PAM by chemical synthesis. DLC-PAM belongs to side-chain liquid crystal polymer, and it can show the properties of it¡¦s discotic liquid crystal function. One of the properties is absorption of visible light. By observing the UV-Vis spectrum, we can realize the absorption band is located between 200 ~ 450 nm and confirm that it is able to be a photo-sensitized dye. Another property of discotic liquid crystal is the self-assembly ability, the moleculars can assemble into hexagonal columnar structure by themselves, and the property enable discotic liquid crystal to have better mobility. In this part, we can demonstrate DLC-PAM and Acid-6 really have hexagonal columnar structure by X-ray diffractmeter. After qualitative demonstrating and optical analysis, we use DLC-PAM and Acid-6 as photo-sensitized dyes for DSSCs and manufacture two kinds of cells successfully. The more photocurrent occur when the two DSSCs are woking. Besides, the two DSSCs have good performance on power conversion efficiency which can achieve 0.047 % for DLC-PAM and 0.364 % for Acid-6. Therefore, in this research we prove that DLC-PAM and Acid-6 are able to be photo-sensitized dyes for DSSCs and successfully demonstrate that using the two materials to manufacture DSSCs is feasible.

Viscoelastic surfactant have found numerous application in the oil fields as fracturing and matrix acidizing fluid additives in the recent years. They have the ability to form long worm-like micelles with the increase in pH and calcium concentration, which results in increasing the viscosity and elasticity of partially spent acids. On one hand, concentration of surfactant in the fluids has profound effects on their performance downhole. Additionally, there is continuous debate in the industry on whether the gel generated by these surfactants causes formation damage, especially in dry gas wells. Therefore, being able to analyze the concentration of these surfactants in both live and spent acids is of great importance for production engineers who apply surfactant-based fluids in the oil fields. In the present work, a two-phase titration method was optimized for quantitative analysis of a carboxybetaine viscoelastic surfactant, and surfactant retention in calcite cores was quantitatively determined by two phase titration method and the benefits of using mutual solvents to break the surfactant gel formed inside the cores was assessed. On the other hand, high temperatures and low pH are usually involved in surfactant applications. Surfactants are subjected to hydrolysis under such conditions due to the existence of a peptide bond (-CO-NH-) in their molecules, leading to alteration in the rheological properties of the acid. The impact of hydrolysis at high temperatures on the apparent viscosity of carboxybetaine viscoelastic surfactant-based acids was evaluated in the present study, and the mechanism of viscosity changes was determine by molecular dynamics (MD) simulations. Our results indicate that, first, significant amount of surfactant has been retained in the carbonate matrix after acidizing treatment and there is a need to use internal breakers when surfactant-based acids are used in dry gas wells or water injectors. Second, hydrolysis at high temperatures has great impact on surfactant-acid rheological properties. Short time viscosity build-up and effective gel break-down can be achieved if surfactant-acid treatments are carefully designed; otherwise, unexpected viscosity reduction and phase separation may occur, which will affect the outcome of acid treatments.

Recent advances in the self-assembly of highly organized structures of organic semiconducting molecules by controlled non-covalent interactions has opened avenues for creating materials with unique optical and electrical properties. The main focus of this thesis lies in the synthesis and self-assembly of n-type perylene based organic semiconducting molecules into highly organized materials. Perylene based molecules used in this study are perylene diimide (PTCDI, two side-chains), perylene mono imide (m-PTCI, one side-chain), perylene tetracarboxylic acid (PTCA, no side-chain) and tetra-alkali metal salts of PTCA (M 4 -PTCA, no side-chain), which are synthesized from the parent perylene tetracarboxylic dianhydride (PTCDA). The self-assembly of these molecules have been performed using solution processing methods (dispersion, phase-transfer, and phase-transfer at high temperature) by taking advantage of the changes in solubility of the molecules, wherein the molecular interactions are maximized to favorably allow for the formation of highly organized structures. Dimension control (1D, 2D and 3D structures) of self-assembly has been obtained for different perylene based molecules by appropriate design of the molecule followed by controlling the conditions of assembly. In case of PTCDI, a new solution processing method phase-transfer at high temperature (2L-HT) allowed for the controlled formation of extremely long and fluorescent 1D structure. For the m-PTCI molecules the organization by the 2L-HT method was found to result in highly organized, single-crystalline, fluorescent 2D sheets. In the case of perylene based molecules with no side-chains two different methods have been developed for the realization of organized 1D nanostructures. The first method utilizes the chemical conversion of a highly soluble PTCA into 1D nanofibers of the parent insoluble perylene tetracarboxylic anhydride. The second method utilizes the assembly of tetra potassium salt of PTCA (K 4 -PTCA) into 1D nanostructures. Furthermore, it has been demonstrated that these 1D nanostructures can be chemically converted to two different chemical species, both of which still retain the 1D morphological characteristic, though with changes in the size. Various functional self-assembled structures developed in this thesis opens up new avenues to explore structure-property-function relationships and their use in applications such as sensors, electronics and opto-electronic devices.

Metal organic framework (MOF) has emerged as a new class of porous, thermally stable material which has attracted great attention due to their wide applications in gas storage, separation, catalysis etc. Self-assembly is the operative mechanism of MOFs syntheses; however, the control of MOF self-assembly is still a challenge in the construction of predetermined, structurally well-defined MOFs. The goal of the research is to arrive at multidimensional, highly porous and functional MOFs via hierarchical assembly of smaller molecular building blocks and, at the same time, to examine the possibilities for different interesting molecular textures. This goal is to be accomplished by the knowledge of ligand coordination mode, and geometry as well as logical choices of ligands and metals from which the MOFs are to be constructed from. Preparations of novel frameworks as well as other interesting molecular architectures are highlighted with their structures characterized.

<p>Self-assembly is a pervasive natural phenomenon that gives rise to complex structures and functions. It describes processes in which a disordered system of components form organized structures as a consequence of specific, local interactions among the components themselves, without any external direction. Biological self-assembled systems, evolved over billions of years, are more intricate, more energy efficient and more functional than anything researchers have currently achieved at the nanoscale. A challenge for human designed physical self-assembled systems is to catch up with mother nature. I argue through examples that DNA is an apt material to meet this challenge. This work presents:</p><p>1. 3D self-assembled DNA nanostructures.</p><p>2. Illustrations of the simplicity and power of toehold-mediated strand displacement interactions.</p><p>3. Algorithmic constructs in the tile assembly model.</p> / Dissertation

Metal organic framework (MOF) has emerged as a new class of porous, thermally stable material which has attracted great attention due to their wide applications in gas storage, separation, catalysis etc. Self-assembly is the operative mechanism of MOFs syntheses; however, the control of MOF self-assembly is still a challenge in the construction of predetermined, structurally well-defined MOFs. The goal of the research is to arrive at multidimensional, highly porous and functional MOFs via hierarchical assembly of smaller molecular building blocks and, at the same time, to examine the possibilities for different interesting molecular textures. This goal is to be accomplished by the knowledge of ligand coordination mode, and geometry as well as logical choices of ligands and metals from which the MOFs are to be constructed from. Preparations of novel frameworks as well as other interesting molecular architectures are highlighted with their structures characterized.

In an age in which the microchip is ubiquitous, the rewards for novel methods of microfabrification are great, and the vast possibilities of nanotechnology lie just a little ahead. Various methods of microlithography offer differing benefits, and even as older techniques such as optical lithography are being refined beyond what were once considered their upper limits of resolution, new techniques show great promise for going even further once they reach their technological maturity. Recent developments in optical lithography may allow it to break the 100-nm limit even without resorting to x-rays.

Compared to 'conventional' materials made from metal, glass, or ceramics, protein-based materials have unique mechanical properties. Furthermore, the morphology, mechanical properties, and functionality of protein-based materials may be optimized via sequence engineering for use in a variety of applications, including textile materials, biosensors, and tissue engineering scaffolds. The development of recombinant DNA technology has enabled the production and engineering of protein-based materials ex vivo . However, harsh production conditions can compromise the mechanical properties of protein-based materials and diminish their ability to incorporate functional proteins. Developing a new generation of protein-based materials is crucial to (i) improve materials assembly conditions, (ii) create novel mechanical properties, and (iii) expand the capacity to carry functional protein/peptide sequences. This thesis describes development of novel protein-based materials using Ultrabithorax, a member of the Hox family of proteins that regulate developmental pathways in Drosophila melanogaster . The experiments presented (i) establish the conditions required for the assembly of Ubx-based materials, (ii) generate a wide range of Ubx morphologies, (iii) examine the mechanical properties of Ubx fibers, (iv) incorporate protein functions to Ubx-based materials via gene fusion, (v) pattern protein functions within the Ubx materials, and (vi) examine the biocompatibility of Ubx materials in vitro . Ubx-based materials assemble at mild conditions compatible with protein folding and activity, which enables Ubx chimeric materials to retain the function of appended proteins in spatial patterns determined by materials assembly. Ubx-based materials also display mechanical properties comparable to existing protein-based materials and demonstrate good biocompatibility with living cells in vitro . Taken together, this research demonstrates the unique features and future potential of novel Ubx-based materials.

The goal of this thesis is to experimentally characterize the flyability of current generation read/write heads over media patterned to densities above the superparamagnetic limit. The superparamagnetic limit is the physical limit to magnetic storage density. In magnetic storage, superparamagnetism is the uncontrollable switching of stored bits during the lifespan of a hard disk. Theoretical analysis has predicted that densities of ~50 Gbit/in2 are not possible using traditional continuous media. One strategy to achieve high storage density, above the superparamagnetic limit, is patterned media. With patterned media the physical separation of magnetic domains increases their stability. One of the major challenges of development of patterned media is achieving acceptable flyability of the read/write head. In that vein, a test stand is built to measure head liftoff speed, head to disk intermittent contact and head fly height. Tangential friction, an indicator of head liftoff is measured by a Wheatstone bridge strain circuit attached to a cantilever beam. Intermittent contact is quantified by the amount of noise emanating from the interface, which is measured by a high frequency acoustic emission sensor. Head fly height is measured indirectly with a capacitance circuit built around the head to disk interface. Experimental samples of current generation read/write heads and media are obtained from industry. Current generation media is patterned using focused ion beam milling to a density of 10 Gbit/in2. Other, extremely dense samples, above 700 Gbit/in2, are created via thin film self assembly on silicon substrate. Conclusions on slider head flyability over patterned media are based on comparison with flyability over non-patterned media. It is demonstrated that loss of hydrodynamic lubrication is small for small pattern regions with high conserved surface area ratio. Conserved surface area ratio is defined as total surface area minus etched surface area all divided by the total surface area of the storage media. For wafer scale patterned media with low conserved surface area ratio, head liftoff cannot be achieved at designed normal load. However, a 50% reduction of load allows slider head liftoff.

The successful applications of nanoparticles require the ability to tune their properties by controlling size and shape at the nanoscale. In metal nanomaterial research, the optical properties have been of interest especially because of the applications to medical diagnostics and nanooptics. It is important to prepare nanoparticles of well-defined shape and size for properly characterizing the optical properties. We describe improved seed mediated synthesis of gold nanorods (GNRs) producing a high yield of NRs with low polydispersity and few byproducts. The efficient separation of GNRs from mixture of shapes is achieved by understanding the hydrodynamics of nanoparticles undergoing centrifugation. The optical properties of resulting refined GNRs are compared to predictions of existing theories, and the main parameters affecting them are discussed. GNRs with well defined aspect ratios are introduced into a polyvinyl alcohol matrix by means of solution-casting techniques. The film is drawn to induce the uniaxial alignment of GNRs to be used as color polarizing filters. We prepare GNR polarizing filter with different peak positions ranging from visible to near infra red by using different aspect ratio of NRs. To utilize GNRs to make nanoscale devices, spatial organization is required. We characterize the self-assembly of GNRs observed on a TEM grid. The drying process is accompanied by complex hydrodynamic and thermodynamic events, which create rich range of patterns observed. Being anisotropic in shape, the rods can form liquid crystal (LC) assemblies above a certain concentration. We observed LC phase of GNRs by resorting to an evaporation of aqueous NR solution. The convective flow caused by the solvent evaporation carries NRs from the bulk solution to solid-liquid-air interface, which makes the solution locally very concentrated driving the phase transition of NRs. We calculate the order parameter from various assemblies observed, and compare the observed phase behavior to the one expected on the basis of theory.