Ce travail décrit la séparation de microphase à l'état solide d'un copolymère dibloc comprenant un bloc hautement biocompatible poly [2 - (méthacryloyloxy) éthyl phosphorylcholine] et un bloc pH-sensible poly [2 - (diisopropylamino) méthacrylate d'éthyle] (PMPC-b-PDPA). L'auto-assemblage d'un copolymère dibloc amphiphiles à base de polystyrène (PS) et le poly (acide acrylique) (PAA), a été étudié en suspension aqueuse, et leur décoration par du chitosane, afin de vérifier leur capacité à encapsuler et à libérer par voie transdermique la finastéride, une molécule stéroïdiens inhibiteur de la enzyme 5-alpha-réductase, qui a été recommandée pour le traitement de l'alopécie androgénétique. La morphologie des films PMPC30-b-PDPA60 a été analysée par SAXS et (S) TEM. Films du PMPC30-b-PDPA60 préparés dans une solution de l'éthanol à température ambiante présentent une morphologie cylindrique, qui subit une transition ordre-ordre sur un recuit thermique à 170 ° C: la structure lamellaire résultant coexiste avec une proportion de cylindres organisée dans une phase hexagonale compacte. En revanche, les films du copolymère préparé à partir de méthanol ne subissent pas la même transition morphologique, résultant dans des structures mal organisées, indépendante de traitement thermique. Enfin, les structures lamellaires sont obtenues directement à partir d'une solution aqueuse à pH 4, sans traitement thermique. Ces systèmes offrent une nouvelle alternative pour la fabrication de structures lamellaires constituées d'un matériau biomimétique et anti-fouling, élargissant l'éventail des possibilités dans le domaine de l'ingénierie macromoléculaire.Une autre stratégie adoptée dans ce travail a été basé sur le développement de nanoparticules bien organisé avec des propriétés de surface nature bioinspirés, formé entre polymersomes chargés négativement à base des copolymères à blocs de polystyrène (PS) et le poly (acide acrylique) (PAA) décorés avec du chitosane, un polysaccharide de charge opposée. Le rôle de l'adsorption du chitosane avec deux poids moléculaires distincts (chitosane oligosaccharides et du chitosane avec un faible poids moléculaire) sur la surface des nanoparticules PS139-b-PAA17 et des nanoparticules PS404-b-PAA63 ont été démontrés par diffusion dynamique de la lumière, potentiel zêta et caractérisation morphologiques. En présence du chitosane, le potentiel zêta de polymersomes devient positif. Ce résultat a été interprété en termes d'interactions électrostatiques, qui induisent une adsorption du chitosane sur la surface des polymersomes. Ce résultat a été confirmé par une observation comparative par microscopie entre des polymersomes et des polymersomes décorées. Polymersomes avec un diamètre <200 nm et une distribution granulométrique relativement étroite ont été obtenus pour les deux systèmes. L'effet de la décoration des nanoparticules par du chitosane sur la perméation cutanée in vitro du finastéride, incorporé dans la paroi hydrophobe de polymersomes, a également été évaluée. La pénétration cutanée du finastéride a été estimée par les paramètres de perméabilité tels que le flux, temps de latence et du coefficient de perméabilité de la finastéride. Une amélioration de la perméation du finastéride à partir des nanoparticules a été observée, en particulier à partir de nanoparticules décorées avec du chitosane. Le polymersome PS404-b-PAA63 décorées avec du chitosane semble être le système le plus approprié car il favorisé une meilleure rétention du médicament dans la peau et les faibles valeurs de flux de perméation, suggérant que le système fournit un véhicule de remplacement pour l'administration transdermique de finastéride. / This work describes the microphase separation in bulk of an diblock copolymer comprising a highly biocompatible poly[2-(methacryloyloxy)ethyl phosphorylcholine] block and a pH-sensitive poly[2-(diisopropylamino) ethyl methacrylate] block (PMPC-b-PDPA). The self-assembly of an amphiphilic diblock copolymer based on polystyrene (PS) and poly(acrylic acid) (PAA) was studied in terms of their decoration with the chitosan, verifying their ability to incorporate and transdermally release the drug finasteride, a steroidal molecule 5-alpha-reductase inhibitor that has been recommended for the treatment of androgenetic alopecia. The morphology of PMPC30-b-PDPA60 films was analyzed using SAXS and (S)TEM. PMPC30-b-PDPA60 films cast from ethanol solution at room temperature exhibit a thermodynamically quasi-stable cylindrical morphology, which undergoes an order-order transition upon thermal annealing at 170 oC: the resulting lamellar structure coexists with a minor proportion of cylinders organized into a hexagonal compact phase. In contrast, copolymer films cast from methanol do not undergo the same morphological transition. Instead, short-range liquid-like structures are obtained regardless of the annealing processes. Finally, direct self-assembly to form a lamellar morphology at room temperature can be achieved by solvent-casting from aqueous solution at pH 4. These systems offer a new alternative for the fabrication of lamellar structures in which one layer is biomimetic and non-fouling, expanding the range of possibilities in the macromolecular engineering field. Another strategy adopted in this work was based on the development of well-organized nanoparticles with nature-bioinspired surface properties, formed between negatively charged polymersomes based on polystyrene (PS) and poly(acrylic acid) (PAA) block copolymers decorated with chitosan, an oppositely charged polysaccharide. The role of chitosan with two distinct molecular weights (chitosan oligosaccharide and low molecular weight chitosan) adsorption on the surface of oppositely charged PS139-b-PAA17 and PS404-b-PAA63 nanoparticles were demonstrated by dynamic light scattering measurements, zeta potential and morphological characterization. In the presence of chitosan, the zeta potential of polymersomes becomes positive. This result was interpreted in terms of electrostatic interactions, which induce a flat adsorption of the chitosan on the surface of the polymersomes. This result was further confirmed by a comparative observation by microscopy of bare and chitosan-decorated polymersomes. Polymersomes with a diameter < 200 nm and a relatively narrow size distribution were obtained for both systems. The effect of chitosan decoration of self-assembled nanoparticles on skin penetration in vitro of finasteride was also evaluated, once incorporated in the wall hydrophobic of polymersomes. The skin permeation through pig ear skin of finasteride was estimated by the permeability parameters such as flux, lag time and permeability coefficient of finasteride. An improved permeation of finasteride from the nanoparticle system was observed, especially from nanoparticles decorated with chitosan. The PS404-b-PAA63 polymersome decorated with chitosan seems to be the most appropriate system since it provided higher drug retention in skin and low permeation flux values, suggesting that the PS-b-PAA/chitosan system provides an alternative for transdermal drug delivery system of finasteride.

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Leung Yee Pan = 利用有機金屬化學氣相沉積方法生長一維硒化鋅鈉米結構 / 梁懿斌. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 80-82). / Text in English; abstracts in English and Chinese. / Leung Yee Pan = li yong you ji jin shu hua xue qi xiang chen ji fang fa sheng chang yi wei xi hua xin na mi jie gou / Liang Yibin. / Acknowledgements --- p.ii / Abstract --- p.iii / Chapter Chapter 1 - --- Introduction --- p.1 / Chapter 1.1 --- Background --- p.1 / Chapter 1.2 --- Motivation --- p.3 / Chapter 1.2.1 --- ZnSe --- p.3 / Chapter 1.2.2 --- MOCVD --- p.3 / Chapter 1.3 --- Our Work --- p.4 / Chapter Chapter 2 - --- Experiment --- p.5 / Chapter 2.1 --- MOCVD System --- p.5 / Chapter 2.2 --- Metalorganic Sources --- p.5 / Chapter 2.3 --- Substrates --- p.7 / Chapter 2.4 --- Substrate Preparations --- p.7 / Chapter 2.5 --- Preheating (Applied Only when Using GaAs Substrates) --- p.7 / Chapter 2.6 --- Growth of Epi-layer (Applied Only when Using GaAs Substrates) --- p.8 / Chapter 2.7 --- Growth of ZnSe Nanowires on Si(100) and ZnSe/GaAs(100) --- p.8 / Chapter 2.8 --- The Samples --- p.9 / Chapter Chapter 3 - --- Characterization --- p.10 / Chapter 3.1 --- Surface Morphologies --- p.10 / Chapter 3.1.1 --- Scanning Electron Microscopy --- p.10 / Chapter 3.1.2 --- Atomic Force Microscopy --- p.12 / Chapter 3.2 --- Structural Properties - X-Ray Diffraction --- p.13 / Chapter 3.3 --- Optical Properties - Photoluminescence --- p.15 / Chapter 3.4 --- Other Techniques --- p.16 / Chapter Chapter 4 - --- Results --- p.17 / Chapter 4.1 --- ZnSe Nanowires Grown on Si(100) --- p.17 / Chapter 4.1.1 --- Effect of Growth Temperature --- p.17 / Chapter 4.2 --- Growth of ZnSe Nanowires on GaAs( 100) - The First Trial --- p.20 / Chapter 4.3 --- Optimizing the ZnSe Epi-layer --- p.21 / Chapter 4.3.1 --- Surface of GaAs(100) --- p.21 / Chapter 4.3.2 --- ZnSe Epi-layer Grown at Different Reactor Pressures --- p.22 / Chapter 4.4 --- Importance of Au --- p.26 / Chapter 4.5 --- Growth of ZnSe Nanowires on GaAs(lOO) - A Systematic Study --- p.28 / Chapter 4.5.1 --- Growth Rates --- p.28 / Chapter 4.5.2 --- Overall Morphologies --- p.32 / Chapter 4.5.3 --- Classifying the Morphologies --- p.37 / Chapter 4.5.4 --- Abundances of Different Morphologies of Different Samples --- p.40 / Chapter 4.5.5 --- Growth Direction --- p.45 / Chapter 4.5.6 --- Structure of the Nanowires --- p.50 / Chapter 4.5.7 --- Optical Properties of the Nanowires --- p.54 / Chapter Chapter 5 - --- Discussions --- p.57 / Chapter 5.1 --- Overview of the MOCVD Process --- p.57 / Chapter 5.1.1 --- Effects of Growth Temperature on Growth Rate of MOCVD --- p.58 / Chapter 5.1.2 --- Effects of Reactor Pressure on Growth Rate of MOCVD --- p.59 / Chapter 5.2 --- Effect of Reactor Pressure on the Growth Rate of the Nanowires --- p.60 / Chapter 5.3 --- Growth Mechanisms of the Nanowires --- p.64 / Chapter 5.3.1 --- VLS Mechanism --- p.64 / Chapter 5.3.2 --- Spiral Growth Mechanism --- p.66 / Chapter 5.3.3 --- Reentrant Corner Mechanism --- p.67 / Chapter 5.3.4 --- Roles of Au Particles and ZnSe Epi-layer --- p.68 / Chapter 5.3.5 --- Growth Mechanisms of Different Types of Nanowires --- p.69 / Chapter 5.3.6 --- Effect of Growth Temperature --- p.71 / Chapter 5.4 --- Quality of the Nanowires --- p.72 / Chapter 5.5 --- "Remarks of the AFM Experiments and the ""Transferred"" Samples" --- p.72 / Chapter Chapter 6 - --- Conclusions --- p.75 / Appendices --- p.77 / Chapter I - --- "Estimation of the mass, other than the nanowires, contributed to the sample" --- p.77 / Chapter II - --- Calculation of the growth angle with respect to the surface normal --- p.78 / References --- p.80

by Lai Yiu Wai. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references. / Abstract in English and Chinese. / Abstract / Abstract (Chinese) / Table of Contents / List of Figures / List of Tables / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- Overview --- p.1-1 / Chapter 1.2 --- Conventional recording --- p.1-2 / Chapter 1.3 --- Superparamagnetism --- p.1-2 / Chapter 1.4 --- Possible solutions --- p.1-4 / Chapter 1.4.1 --- Perpendicular recording --- p.1-5 / Chapter 1.4.2 --- Patterned media --- p.1-6 / Chapter 1.4.3 --- High Ku material for recording media --- p.1-7 / Chapter 1.5 --- FePt-based material research 1 - --- p.1-8 / Chapter 1.6 --- Project goal --- p.1-11 / Reference --- p.1-12 / Chapter Chapter 2 --- Sample preparation and characterization techniques / Chapter 2.1 --- Pulsed filtered vacuum arc deposition (PFVAD) --- p.2-1 / Chapter 2.1.1 --- Sample preparation --- p.2-4 / Chapter 2.2 --- Rutherford backscattering spectroscopy (RBS) --- p.2-4 / Chapter 2.3 --- X-ray diffraction (XRD) --- p.2-6 / Chapter 2.4 --- Vibrating sample magnetometery (VSM) --- p.2-7 / Chapter 2.5 --- Transmission electron microscopy (TEM) --- p.2-9 / Reference --- p.2-10 / Chapter Chapter 3 --- Characterization of FePt-C nanocomposite thin film / Chapter 3.1 --- Experiment design --- p.3-1 / Chapter 3.2 --- Experiment detail --- p.3-1 / Chapter 3.3 --- Results and discussion --- p.3-3 / Chapter 3.3.1 --- NRBS measurements --- p.3-3 / Chapter 3.3.2 --- XRD measurements --- p.3-8 / Chapter 3.3.3 --- VSM measurements --- p.3-14 / Chapter 3.3.4 --- Some preliminary results on effects of post- deposition implantation --- p.3-23 / Chapter 3.3.5 --- TEM images --- p.3-26 / Chapter 3.3.6 --- Overall discussion --- p.3-29 / Chapter 3.3.6.1 --- Total film thickness effect --- p.3-29 / Chapter 3.3.6.2 --- Degree of ordering from XRD (001)/(002) peak intensity ratio --- p.3-33 / Chapter 3.3.6.3 --- C spacer thickness effect --- p.3-34 / Chapter 3.3.6.4 --- Implantation effect --- p.3-35 / Chapter 3.4 --- Summary --- p.3-35 / Reference --- p.3-36 / Chapter Chapter 4 --- Characterization of FePt-Cu nanocomposite thin film / Chapter 4.1 --- Experiment design --- p.4-1 / Chapter 4.2 --- Experiment detail --- p.4-1 / Chapter 4.3 --- Results and discussion --- p.4-3 / Chapter 4.3.1 --- RBS measurements --- p.4-3 / Chapter 4.3.2 --- XRD measurements --- p.4-7 / Chapter 4.3.3 --- VSM measurements --- p.4-9 / Chapter 4.3.4 --- Discussion --- p.4-12 / Chapter 4.3.4.1 --- Total film thickness effect --- p.4-12 / Chapter 4.3.4.2 --- Cu spacer thickness effect --- p.4-13 / Chapter 4.4 --- FePt films without additive --- p.4-16 / Chapter 4.5 --- Summary --- p.4-17 / Reference --- p.4-18 / Chapter Chapter 5 --- Conclusion and future works / Chapter 5.1 --- Conclusion --- p.5-1 / Chapter 5.2 --- Future works --- p.5-3 / Reference --- p.5-4 / Appendix 1 / Appendix 2

Wong, Man Keung. / "November 2010." / Thesis (M.Phil.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references. / Abstracts in English and Chinese. / Abstract --- p.i / Table of contents --- p.iii / List of Figures --- p.vi / List of Tables --- p.ix / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Background --- p.1 / Chapter 1.2 --- History of organic photovoltaic cells --- p.2 / Chapter 1.2.1 --- Single layer organic photovoltaic cells --- p.2 / Chapter 1.2.2 --- Bilayer organic photovoltaic cells --- p.3 / Chapter 1.2.3 --- Bulk Heterojunction organic photovoltaic cells --- p.6 / Chapter 1.3 --- Device physics of organic photovoltaic cells --- p.9 / Chapter 1.4 --- Device fabrication and characterization --- p.12 / Chapter 1.5 --- Thesis outline --- p.14 / Chapter Chapter 2 --- Instrumentation --- p.18 / Chapter 2.1 --- Keithley 236 source measure unit --- p.18 / Chapter 2.2 --- CHI 660C electrochemical instrument --- p.18 / Chapter 2.3 --- Tensor Alpha Step 500 Profilometer --- p.19 / Chapter 2.4 --- Fourier Transform Infrared (FTIR) spectroscopy --- p.20 / Chapter 2.5 --- Thermogravimetric Analysis --- p.22 / Chapter 2.6 --- X-ray Diffraction --- p.23 / Chapter 2.7 --- Scanning electron microscopy --- p.24 / Chapter 2.8 --- Atomic force microscopy --- p.26 / Chapter Chapter 3 --- Surface functionalization of Carbon Nanotube --- p.28 / Chapter 3.1 --- Introduction --- p.28 / Chapter 3.2 --- Oxidative treatment --- p.28 / Chapter 3.2.1 --- Experimental procedures --- p.28 / Chapter 3.2.2 --- Characterization --- p.29 / Chapter 3.3 --- Hydrothermal treatment --- p.35 / Chapter 3.3.1 --- Experimental procedures --- p.35 / Chapter 3.3.1.1 --- Synthesis of MWCNTols --- p.35 / Chapter 3.3.1.2 --- Synthesis of MWCNT-PEDOT --- p.36 / Chapter 3.3.2 --- Characterization --- p.37 / Chapter 3.4 --- Summary --- p.42 / Chapter Chapter 4 --- P3HT/f-CNT/PCBM Composites for Organic Photovoltaic Cells --- p.45 / Chapter 4.1 --- Introduction --- p.45 / Chapter 4.2 --- Fabrication procedures --- p.48 / Chapter 4.3 --- IV characteristics of organic photovoltaic cells --- p.51 / Chapter Chapter 5 --- Vertically aligned poly(3-hexylthiophene) nanobrushes of high aspect ratio for photoelectrochemical solar cells --- p.60 / Chapter 5.1 --- Introduction --- p.60 / Chapter 5.2 --- Sample preparation --- p.63 / Chapter 5.3 --- IV characteristics of P3HT nanobrushes --- p.65 / Chapter 5.4 --- AFM and XRD analysis --- p.66 / Chapter 5.5 --- Summary --- p.71 / Chapter Chapter 6 --- Conclusions --- p.74 / Chapter 6.1 --- Conclusions --- p.74

In this project, nano-sized gallium oxide and indium oxide produced by ion implantation of nitrogen/carbon and subsequent rapid thermal annealing (RTA) have been investigated. The material synthesis technique is based on using implantation of different species, which include nitrogen, carbon, oxygen and argon, with variable implant dosage to form an amorphous surface layer on GaAs or InP substrates. RTA then provides the required thermal energy for the amorphous material to re-crystallize. We found that the type of implanted species play an important role in controlling the material for nation during the RTA stage. Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were conducted to provide detailed characterization on the samples. For the nitrogen/carbon implanted samples, RTA at 950&deg;C resulted in the formation of single crystalline Ga2O3 nano-ribbons on the sample surface. These Ga2O3 ribbons possess strong visible photoluminescence and cathodoluminescence. For the carbon implanted InP samples, In2O3 nanowires were found on the InP sample surface when RTA was performed at 750&deg;C. However, In2O 3 nanowires only occurred when gold was present. On the other hand, when the nitrogen implanted samples were annealed in pure nitrogen ambient, a Raman peak at 577cm-1 associated with GaN was observed. Cross-sectional TEM showed that the thickness of the region containing GaN was about 40nm. We also used the synthesized GaN as a buffer layer to grow ZnO film by using MOCVD. The possible formation mechanisms of these nanomaterials and the role of the implanted species are discussed. For the nanowires with gold nano-particles at the free end, we believe that they are synthesized by vapour-liquid-solid (VLS) mechanism. On the other hand, the growth of nano-wires in the cases where no gold nano-particles on the free end may be explained on the basis of a vapour-solid (VS) mechanism. For the case of carbon or nitrogen implantation, carbon works as a reduction agent and nitrogen favours the formation of group III nitride template, which may lead of the growth of nano-wires. / Lo, Kwong Chun. / "March 2008." / Adviser: Aaron H. P. Ho. / Source: Dissertation Abstracts International, Volume: 70-03, Section: B, page: 1887. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (p. 112-119). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

Biocompatible anatase TiO2 single-crystals with 27 % -- 50 % chemically reactive facets were obtained in 90 minutes by using a microwave-assisted method. The preparation involved an aqueous solution of titanium tetrafluoride and an ionic liquid (1-methyl-imidazolium tetrafluoroborate). The as-obtained TiO2 single-crystals exhibited a truncated tetragonal bipyramidal shape. By simply changing the concentration of the ionic liquid, the level of reactive facets can be continuously tuned from 27 % to 50 %. The use of microwave heating is critical as it allows rapid and uniform heating of the reaction mixture. The TiO2 single-crystals were characterized by XRD, TEM, XPS and FESEM. The products exhibited excellent photocatalytic efficiency for both oxidation of nitric oxide in air and degradation of organic compounds in aqueous solution under UV light irradiation. The relationship between the physicochemical properties and the photocatalytic performance of the samples was discussed. The TiO2 single-crystals were found to be nontoxic using Zebrafish (D. rerio) as a model. / Bismuth oxyhalide semiconductors (BiOBr, BiOCl) with marigold-like open architectures were also prepared by a solvothermal method involving imidazolium-based ionic liquids and ethylene glycol. The 3D self-assembled marigold-like materials were effective photocatalysts for degrading organic pollutants and generating hydrogen. The main advantages of the new materials were large surface area, high surface-to-bulk ratio, facile species transportation, and ease of recovery and regeneration. / By using a microwave-assisted hydrothermal method involving titanium tetrafluoride and a tetrafluoroborate-based ionic liquid (1-butyl-3-methyl-imidazolium-tetrafluoroborate), a micro-sheet anatase TiO2 single crystal photocatalyst with remarkable 80 % reactive facets was synthesized. The as-obtained TiO2 single-crystal exhibited a truncated tetragonal bipyramidal shape. The high reactivity of facets made these single crystals highly photocatalytically active. They were easily recyclable and thermally stable up to 800 &deg;C. / Furthermore, a simple and environmentally benign approach for the synthesis of photocatalytically active rutile TiO2 mesocrystals was developed. It was a microwave-assisted hydrothermal method involving titanium(III) chloride as the only reactant. The resulting 1D rutile nanowires could easily assemble into 3D hierarchical architectures without the help of surfactants or additives. The average aspect ratio for the nanowires was 267. The BET specific surface area of the mesocrystal was 16 m2/g. / Part I: Size-tunable monodispersed hierarchical metallic Ni nanocrystals (58-190 nm in diameter) were prepared by the reduction of Ni2+ with hexadecylamine under atmospheric pressure. The diameter of the particles could be tuned by simply changing the reaction time. A reaction mechanism was proposed and the relationships between the size, hierarchical surfaces and the magnetic properties were investigated. The as synthesized Ni crystals exhibited higher coercivities than the bulk metallic material owing to the reduced size and the hierarchical surface structure. The saturation magnetization (Ms) and the ratio of remanence to saturation (Mr/Ms) increased with increasing particle size. / Part II: A facile microwave-assisted solvothermal method was developed for the controlled synthesis of novel 3D CdS structures. Dendrite-, star-, popcorn- and hollow sphere-like CdS structures could be obtained by changing the reaction conditions including the reaction temperature and the amounts of reagents and solvents. The results revealed that the final structures were related to the solvent properties such as surface tension and viscosity. The degree of supersaturation was also responsible for the morphology variation and it could be adjusted by the reaction temperature. The CdS products with different morphologies exhibited interesting shape-dependent optical properties and photocatalytic activities. / The optical band energy of the product exhibited an obvious red-shift of 0.2 eV with aspect to that of pure rutile TiO2. This red-shift effect may be ascribed to the high aspect ratio of the rutile nanowires. The products showed excellent photocatalytic activity for NO removal in air and the activity was well maintained after three cycles. Gold modification on the rutile TiO2 resulted in a 50 % improvement in the photocatalytic performance. / This thesis focuses primarily on the preparation of various functional materials with controllable structures and properties. The first part describes the synthesis of materials by solvothermal methods. The second part describes the rapid fabrication of novel semiconductor materials by microwave-assisted methods. / Zhang, Dieqing. / Source: Dissertation Abstracts International, Volume: 72-04, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 189-190). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Yim Wai-leung. / "September 2002." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (p. 117-123). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

Mesoporous titania molecular-sieve thin films have been modified by incorporating guest species either in the pores or on the walls of the structure. The incorporation was realized with the aid of sonochemical processing. The structure, morphology, texture, optical properties, and stability of the resulting nanostructures were characterized by X-ray diffraction, nitrogen adsorption, UV-vis diffuse reflectance spectroscopy, infrared spectroscopy, photoluminesent spectroscopy, scanning electron microscopy, transmission electron microscopy, thermalgravimetric and differential thermal analyses. The photocatalytic and catalytic properties of the mesoporous TiO2-based nanocomposites were evaluated by photocatalytic degradation of organic pollutants, photo-assisted killing of bacteria/cancer-cells, and catalytic oxidation of carbon monoxide. / The thesis includes seven parts. The first part describes the pore-wall chemistry and photocatalytic activity of mesoporous nanocrystalline TiO 2 molecular sieve films. The ordered mesoporous TiO2 films show better photocatalytic activities than do the conventional sol-gel-derived TiO2 films toward the degradation of volatile organic pollutants. The reasons for the high activities of the mesostructural films are also discussed. The second part of the thesis reports the incorporation of highly dispersed gold nanoparticles in the mesoporous TiO2 films by a sono- and photochemical approach. The gold nanoparticles thus obtained are well-confined and stabilized in the nanopores of the TiO2 film and therefore, the intrinsic agglomeration of gold nanoparticles is prevented. This eliminates the use of potentially catalyst-poisoning organic ligands for stabilization. This method can also be used to prepare ordered mesoporous Pt/TiO2 and Ag/TiO2 nanocomposites with catalytic and photocatalytic functions as described in the third and forth parts of the thesis. In the fifth part, solid superacid molecular sieves are prepared by the wall-functionalization of the TiO2 film by sulfate groups with the aid of sonication. The resulting 3D-ordered mesoporous sulfated TiO2 superacid molecular sieve films are found to be attractive photocatalysts for environmental applications. The sixth part the thesis reported the sonodeposition of poorly dissolved phthalocyanine dyes onto the surface of the TiO2 film. The dye molecules are attached and stabilized in the pores of the film, avoiding the aggregation of the dye molecules, and consequently achieving effective photosensitization of the TiO2 film. The final part of the thesis describes the preparation of hierarchically macro/mesoporous TiO2 nanostructural photocatalysts. The existence of macroporous channels in a mesoporous TiO2 material improves the photoabsorption efficiency and matter-transfer. These enhance the photocatalytic performance of the bimodal porous TiO2 nanocomposites toward degradation organic pollutants in gas-phase. (Abstract shortened by UMI.) / Wang Xinchen. / "July 2005." / Adviser: Jimmy C. Yu. / Source: Dissertation Abstracts International, Volume: 67-01, Section: B, page: 0293. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

It has been found that the composites of carbon nanotubes (CNTs) and epoxy resin could greatly enhance damping ability while the stiffness is kept at a very high level. In this research, carbon nanotube enhanced epoxy resin is fabricated. The dynamic properties of the nanotube composites are evaluated. A testing apparatus for obtaining composite dynamic properties is set up and measurement procedures are given. Multiple groups of specimens are made for investigations. In particular, the loss factors together with dynamic stiffness are measured for the specimens with different CNT weight ratio. Experimental results show that CNT additive can provide the composite with several times higher damping as compared with pure epoxy. The composite is much stiffer than viscoelastic material (VEM) while the damping is comparable when strain is above certain level. In order to further study the damping mechanism of the CNT composite, models are developed. Composite unit cell models containing single CNT segments are built by using finite element method (FEM). Models with varying CNT orientations are considered in order to describe the behaviors of the randomly oriented CNTs inside the epoxy matrix. Composite loss factors are calculated based on the average ratio of the unit cell energy loss to the unit cell energy input. Calculated loss factors under different strain levels are compared to experimental results. With the validated model, parametric study is thereafter performed. Parameters such as CNT dimensions and CNT alignment orientation are studied. Those factors lead to higher composite damping capacity are identified. / by Dai, Ruoli. / "September 2007." / Adviser: Wei-Hsin Liao. / Source: Dissertation Abstracts International, Volume: 69-08, Section: B, page: 4978. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (p. 93-97). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.