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M.Sc. (Chemistry) / The usefulness of vibrational spectroscopy in identifying surface species, determining adsorbate structures and studying surface reactions has been widely demonstrated. Most of the infrared work on surface species is currently performed using the transmission technique with very thin pressed discs of self supported catalysts. This technique has several disadvantages of which the limited transmission of many catalysts and the loss of available surface area during sample preparation, are but a few. Because of these limitations, information obtained from conventional transmission studies has limited application in terms of understanding and/or improving commercial catalysts. An alternative method which does not suffer from these limitations is Diffuse Reflectance Infrared Fourier Transform Spectroscopy or DRIFTS as it is commonly known. This spectroscopic technique has only recently been extended into the infrared region because of the progress in FTIR instrumentation. Because this is a reflectance technique, the sample is most appropriately a powder, so a high surface area catalyst in its normal powder form can be examined directly without altering its state. A spectroscopic facility which is capable of obtaining DRIFT spectra of adsorbed species at high sensitivity and in situ operating conditions has been established. This facility consists of an FTIR instrument fitted with a diffuse reflectance unit, a heatable high pressure cell and the necessary attachments for gas flow, pressure and temperature control. The project work consisted of an investigation into CO-adsorption on supported rhodium catalysts. By using different combinations of the three parameters: reduction temperature, metal loading and support material, several different species of surface bonded CO have been identified. The three rnein species being: geminal dicarbonyl, linear and bridging CO. As each of these species is associated with a specific Rh-site, conclusions concerning the oxidation state and dispersion of the Rh on the surface could be made. The thermal stability of the different CO-species was studied by increasing the catalyst temperature in a linear fashion. It was found that the geminal dicarbonyl species was the most stable in an oxidising atmosphere. The interconversion of chemisorbed . CO-species at higher temperatures has been spectroscopically verified. A mechanism for CO-dissociation on Rh-catalysts was proposed. In additional experiments the sensitivity of DRIFTS for adsorbed hydrocarbons has been demonstrated. It is concluded that this spectroscopic technique has been proven to be of great significance in the study of surface species on heterogeneous catalysts.

Nanoscience and nanotechnology offer potential routes towards addressing critical issues such as clean and sustainable energy, environmental protection and human health. Specifically, metal and metal oxide nanomaterials are found in a wide range of applications and therefore hold a greater potential of possible release into the environment or for the human to be exposed. Understanding the aqueous phase behavior of metal and metal oxide nanomaterials is a key factor in the safe design of these materials because their interactions with living systems are always mediated through the aqueous phase. Broadly the transformations in the aqueous phase can be classified as dissolution, aggregation and adsorption which are dependent and linked processes to one another. The complexity of these processes at the liquid-solid interface has therefore been one of the grand challenges that has persisted since the beginning of nanotechnology. Although classical models provide guidance for understanding dissolution and aggregation of nanoparticles in water, there are many uncertainties associated with the recent findings. This is often due to a lack of fundamental knowledge of the surface structure and surface energetics for very small particles. Therefore currently the environmental health and safety studies related to nanomaterials are more focused on understanding the surface chemistry that governs the overall processes in the liquid-solid interfacial region at the molecular level. The metal based nanomaterials focused on in this dissertation include TiO2, ZnO, Cu and CuO. These are among the most heavily used in a number of applications ranging from uses in the construction industry to cosmetic formulation. Therefore they are produced in large scale and have been detected in the environment. There is debate within the scientific community related to their safety as a result of the lack of understanding on the surface interactions that arise from the detailed nature of the surfaces. Specifically, the interactions of these metal and metal oxide nanoparticles with environmental and biological ligands in the solutions have demonstrated dramatic alterations in their aqueous phase behavior in terms of dissolution and aggregation. Dissolution and aggregation are among the determining factors of nanoparticle uptake and toxicity. Furthermore, solution conditions such as ionic strength and pH can act as controlling parameters for surface ligand adsorption while adsorbed ligands themselves undergo surface induced structural and conformational changes. Because, nanomaterials in both the environment and in biological systems are subjected to a wide range of matrix conditions they are in fact dynamic and not static entities. Thus monitoring and tracking these nanomaterials in real systems can be extremely challenging which requires a thorough understanding of the surface chemistry governing their transformations. The work presented in this dissertation attempts to bridge the gap between the dynamic processing of these nanomaterials, the details of the molecular level processes that occur at the liquid-solid interfacial region and potential environmental and biological interactions. Extensive nanomaterial characterization is an integral part of these investigations and all the materials presented here are thoroughly analyzed for particle size, shape, surface area, bulk and surface compositions. Detailed spectroscopic analysis was used to acquire molecular information of the processes in the liquid-solid interfacial region and the outcomes are linked with the macroscopic analysis with the aid of dynamic and static light scattering techniques. Furthermore, emphasis is given to the size dependent behavior and theoretical modeling is adapted giving careful consideration to the details of the physicochemical characterization and molecular information unique to the nanomaterials.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第22465号 / 工博第4726号 / 新制||工||1738(附属図書館) / 京都大学大学院工学研究科分子工学専攻 / (主査)教授 関 修平, 教授 水落 憲和, 准教授 菅瀬 謙治, 教授 梶 弘典 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

<p>Here presents the studies of polymerization kinetics and crosslinking efficiency of nm-resolution striped phases on surface, which depends on lengths of alkyl segments and headgroup chemistry. While fluorescence readouts offer the overall efficiencies of polymerization and crosslinking transfer, SPM measurements reveal molecular details accounting for reactivity differences. Additionally, this research also demonstrates the utilization of primary amines striped phases on soft materials, achieving post-functionalization and specific  adsorption of nanocrystals, highlighting the versatile applications of this nm-scale chemistry boundary.</p>

Functional immobilization and lateral organization of proteins into micro- and nanopatterns is an important prerequisite for miniaturizing analytical and biotechnological devices. In this thesis I present novel and versatile approaches for high contrast surface micropatterning of proteins, artificial membranes and live cells based on maleimide photochemistry. The patterning strategy is carried-out on glass substrates exploiting a poly(ethylene glycol) PEG polymer layer as a compatible scaffold. The flexible PEG cushion prevents unspecific proteins attachment and cell adhesion to surfaces. The versatility of this method is demonstrated by means of different orthogonal chemistries using covalent- and affinity- based interactions for protein immobilization. Furthermore, using maleimide based alkyl-thiol chemistry, I utilized the patterning approach for capturing liposomes and proteoliposomes onto surfaces. Formation of fluid patterned polymer-supported membranes demonstrating lateral diffusion of lipids and proteins was confirmed by biophysical assays. A similar approach was used for micropatterning of transmembrane proteins in surface adhered live cells.