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Chan Wing Kin. / Thesis submitted in: Oct 2004. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references. / Abstracts in English and Chinese. / Abstract --- p.i / Abstract (in Chinese) --- p.iii / Acknowledgement --- p.iv / Table of Contents --- p.vi / List of Figures --- p.xi / List of Tables --- p.xv / List of Schemes --- p.xvi / Abbreviations --- p.xviii / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- General Background of Phthalocyanines --- p.1 / Chapter 1.2 --- General Background of Liquid Crystals --- p.3 / Chapter 1.3 --- Structural Classification of the Mesophases --- p.6 / Chapter 1.3.1 --- The Columnar Liquid Crystals --- p.6 / Chapter 1.3.2 --- The Nematic Phase --- p.10 / Chapter 1.3.3 --- The Lamellar Phase --- p.11 / Chapter 1.4 --- Applications of Columnar Discotic Liquid Crystals --- p.13 / Chapter 1.4.1 --- General Properties of HATn Materials and Phthalocyanines --- p.13 / Chapter 1.4.2 --- Supramolecular Channels and Wires --- p.16 / Chapter 1.4.3 --- Phthalocyanine Based Gas Sensors --- p.21 / Chapter 1.5 --- General Synthesis of Liquid Crystalline Phthalocyanines --- p.23 / Chapter 1.5.1 --- Peripherally Substituted Phthalocyanines --- p.23 / Chapter 1.5.1.1 --- Octakis(alkoxymethy l)phthalocy anines --- p.23 / Chapter 1.5.1.2 --- Octa-alkoxyphthalocyanines --- p.26 / Chapter 1.5.1.3 --- Octa-alkylphthalocyanines --- p.29 / Chapter 1.5.1.4 --- Octakis-(alkoxycarbonyl)phthalocyanines --- p.30 / Chapter 1.5.1.5 --- Octa-(p-alkoxylphenyl)phthalocyanines --- p.32 / Chapter 1.5.1.6 --- Tetrakis[oligo(ethyleneoxy)] phthalocyanines --- p.34 / Chapter 1.5.2 --- Non-Peripherally Substituted Phthalocyanines --- p.35 / Chapter 1.5.2.1 --- Octa(alkoxymethyl)phthalocyanines --- p.35 / Chapter 1.5.2.2 --- Octa-alkylphthalocyanines --- p.37 / Chapter 1.5.3 --- Unsymmetrically Substituted Phthalocyanines --- p.40 / Chapter 1.5.4 --- Liquid Crystalline Metallophthalocyanines --- p.42 / Chapter 1.5.4.1 --- Copper Phthalocyanines --- p.42 / Chapter 1.5.4.2 --- "Manganese, Cobalt, Nickel, and Zinc Phthalocyanines" --- p.43 / Chapter 1.5.4.3 --- Lutetium Phthalocyanines --- p.43 / Chapter 1.5.4.4 --- "Silicon, Tin, and Lead Phthalocyanines" --- p.44 / Chapter 1.6 --- Summary --- p.45 / Chapter 1.7 --- References --- p.47 / Chapter Chapter 2 --- "Syntheses, Aggregation Behavior and Liquid Crystalline Properties of Peripherially Octaalkynyl Phthalocyanines" --- p.57 / Chapter 2.1 --- Synthesis and Characterization of Octaalkynyl Phthalocyanines --- p.57 / Chapter 2.1.1 --- Preparation of Alkynyl Fragment 22 --- p.57 / Chapter 2.1.2 --- Preparation of Alkynyl Phthalonitrile 23 --- p.58 / Chapter 2.1.3 --- "Synthesis and Characterization of [2,3,9,10,16,17,23,24-Octakis(3,4,5-tris (dodecyloxy)phenylethynyl)phthalocyaninato]magnesium(II) (29)" --- p.62 / Chapter 2.2 --- Electronic Absorption of Alkynylated Phthalocyanine 29 --- p.65 / Chapter 2.3 --- Liquid Crystalline Properties of Alkynyl Phthalocyanine 29 --- p.71 / Chapter 2.4 --- Summary --- p.73 / Chapter 2.5 --- Experimental Section --- p.74 / Chapter 2.5.1 --- General Information --- p.74 / Chapter 2.5.2 --- Physical Measurements --- p.74 / Chapter 2.5.3 --- Photophysical Measurements --- p.75 / Chapter 2.5.4 --- Experimental Procedure --- p.76 / Chapter 2.6 --- References --- p.83 / Chapter Chapter 3 --- Facile Synthesis of Liquid Crystalline Phthalocyanines Through Transesterification Reactions --- p.86 / Chapter 3.1 --- Synthesis and Characterization --- p.86 / Chapter 3.1.1 --- "Preparation of 4,5-bis(4-methoxycarbonylphenoxy)phthalonitrile (30)" --- p.86 / Chapter 3.1.2 --- Preparation of Phthalocyanines --- p.87 / Chapter 3.2 --- Electronic Absorption Properties and Aggregation Behavior --- p.91 / Chapter 3.3 --- Liquid Crystalline Properties of Phthalocyanines 31 -37 --- p.101 / Chapter 3.4 --- Summary --- p.104 / Chapter 3.5 --- Experimental Section --- p.105 / Chapter 3.5.1 --- Experimental Procedure --- p.105 / Chapter 3.6 --- References --- p.114 / Chapter Chapter 4 --- "In vitro Photodynamic Activities of Peripherially Octa-substituted Zinc Phthalocyanines with Terminal Mono-, Di- and Triethylene Glycol Chains" --- p.115 / Chapter 4.1 --- Photodynamic Therapy (PDT) --- p.115 / Chapter 4.1.1 --- Brief Introduction of Photodynamic Therapy --- p.115 / Chapter 4.1.2 --- Photophysical Mechanism Involved in PDT --- p.117 / Chapter 4.2 --- Photophysical Properties of Phthalocyanines 34-36 --- p.119 / Chapter 4.2.1 --- An overview of photochemical and photophysical processes --- p.119 / Chapter 4.2.2 --- Spectroscopic and Photophysical Properties of Phthalocyanines 34-36 --- p.122 / Chapter 4.3 --- In vitro Photodynamic Activities --- p.128 / Chapter 4.4 --- Summary --- p.128 / Chapter 4.5 --- Experimental Section --- p.129 / Chapter 4.5.1 --- In vitro Studies --- p.129 / Chapter 4.6 --- References --- p.131 / Appendix --- p.135

As the performance of computers has improved dramatically since the 1990s, many interesting photonic crystal properties have been theoretically and experimentally discovered. For example, the strong coupling between photonic crystal cavities was revealed in the 2000s; many groups have successfully fabricated these cavities and verified strong coupling experimentally using silicon. In this thesis, instead of using silicon, we present new results on photonic crystals made by thin indium tin oxide (ITO) layers. Compared to silicon, ITO is not an ideal material to make a photonic crystal because of its comparatively low refractive index and limited transparency. However, it is an interesting model material for experiments in photoemission electron microscopy (PEEM). ITO has a high conductivity that mitigates surface charge-up in an electron microscope and allows electron emission after 2-photon absorption with visible light. We are interested in PEEM because it enables the visualization of the propagation of light with nanometer resolution, i.e., below the optical diffraction limit. In this thesis, we theoretically study ITO photonic crystals in one or two-dimensions with the help of the finite-difference time-domain (FDTD) software. We analyze the electromagnetic field distribution in a manner that the field distributions can directly be compared to experimental PEEM results. We also simulate the strong coupling effect between neighboring cavities and illustrate it in terms of the classical oscillator model.

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Freeze-injury at the plasma membrane level has been identified as being crucial for the survival of living matter. Since plasma membranes consist of several micro domains that make the structure rather complex, this study attempted to use simple model membranes to investigate the changes of phospholipid bilayers at sub-zero temperatures. Egg yolk L-α-phosphatidylcholine (EPC) and 1, 2-dipalmitoyl-rac-glycero-3-phosphocholine (DPPC) that mimic plasma membranes in their unique ways were used to prepare large unilamellar vesicles (LUV), which were the model membranes of this study. At cooling rates of 0.5 and 10�C/min, LUV were freeze-concentrated in the unfrozen matrix as a result of the advancing extraliposomal ice front and the decreasing phase volume of the unfrozen matrix, both of which led to membrane lesion. At the slow cooling rate of 0.5�C/min, an additional freezing stress imposed by the osmotic gradient across the bilayers, due to the increase of solute concentration in the unfrozen matrix, promoted leakage of LUV. The gel-liquid crystal phase transition temperature of phospholipids played an important role in determining if the LUV could withstand freezing stress when the LUV were held at a defined sub-zero temperature for a given period of holding time. EPC LUV were more leaky than DPPC LUV when they were held at the high sub-zero temperatures and their leakage increased with increasing holding time. The leakiness of EPC LUV could be related to the fluid and deformable nature of the EPC above its phase transition temperature. In contrast, DPPC LUV with a higher gel-liquid crystal phase transition temperature compared to EPC may become increasingly fragile at lower sub-zero temperatures, which led to the increase of leakage when the DPPC LUV were held at the lower sub-zero temperatures. These results indicated that the determination of the fatty acid profile of the plasma membranes was essential to aid in developing the most suitable holding temperature and time during the cryopreservation of biological specimens. Adding to the integrity of LUV that depended on the gel-liquid crystal phase transition temperature of phospholipids, intraliposomal ice formation also depended on the phase transition temperature of phospholipids. Intraliposomal ice formation was only observed for DPPC LUV but not for EPC LUV. In addition to the extraliposomal ice formation, other physical changes such as the eutectic crystallization of sodium chloride (NaCl) and ice mixture on the stability of LUV were also investigated. The eutectic crystallization of NaCl/ice mixture was governed by the intra- and extraliposomal distribution of NaCl and was more likely to occur at the physiological NaCl concentrations compared to lower NaCl concentrations. The eutectic crystallization of NaCl/ice mixture further increased the leakage of LUV. The understanding of the freezing behaviour and the mechanisms of freeze-injury of LUV allowed the use of the current model membranes for further investigations of the cryoprotective actions of cryoprotective agents (CPA). Partial phase diagrams of sugar-salt-water, dimethyl sulfoxide (DMSO)-salt-water and ethylene glycol (EG)-salt-water systems that resembled extraliposomal solute compositions were constructed and the phase volume of ice and unfrozen matrix was estimated from the freezing curves. Ice reduction was the major mechanism by which the non-permeable and permeable CPA protected the LUV from freeze-injury. Other cryoprotective mechanisms of the non-permeable and permeable CPA through the dilution and spacing out of the LUV in the unfrozen matrix as well as the suppression of the eutectic crystallization of NaCl/ice mixture were not ruled out. Non-permeable CPA were more effective in preventing leakage of DPPC than EPC LUV. Unlike the non-permeable CPA, permeable CPA were more effective for EPC than DPPC LUV that had been subjected to freezing and thawing processes. At room temperature, however, DMSO and EG were detrimental to the stability of DPPC LUV. The choice of CPA is strictly dependent on the type of phospholipids that varied in their acyl chain length and phase transition temperature. In summary, this study provides insights of the freeze-injury of LUV and the cryoprotective mechanisms of the non-permeable and permeable CPA which are beneficial to the field of cryopreservation that often depends on empirical trial and error methods. By integrating a comprehensive molecular-based understanding, an optimal cryopreservation procedure could be designed.

Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2007. / Includes bibliographical references (leaves 128-132). Also available in electronic version.

Thesis (M.E.E.)--University of Delaware, 2006. / Principal faculty advisor: James Kolodzey, Dept. of Electrical and Computer Engineering. Includes bibliographical references.

This thesis describes the fabrication and characterization of waveguides in the nonlinear, Raman-active optical crystal potassium gadolinium tungstate (KGW). Ion implantation and femtosecond laser writing techniques are used for the first time to fabricate waveguides in this material. The light ion implanted waveguides using hydrogen ions showed unexpected refractive index increases in the damage regions of approximately 0.3% of the nominal refractive index values for three of the four polarization orientations, with only the highest refractive index polarization exhibiting a refractive index decrease of approximately 0.2%. Waveguides fabricated using high-energy carbon, oxygen and fluorine ion irradiations resulted in strongly confining waveguides with wide amorphous damage regions. Carbon ion irradiation of KGW showed the most promise, with sharp step-like waveguides with a maximum refractive index change of delta-n=0.2 with excellent preservation of the Raman properties in the waveguide core. Microreflectivity measurements on the carbon ion irradiated sample revealed unexpected intermittent refractive index changes in the core region, a feature not detected using standard characterization techniques found in the literature. The oxygen ion irradiation of KGW also generated strongly confining waveguides with a maximum refractive index change of delta-n=0.17, however the Raman performance was shown to be reduced to less than 50% in the waveguide cores. Fluorine ion irradiations of KGW resulted in amorphous regions fabricated in the surface regions, offering promise for masking techniques for creating two-dimensional structures. The waveguides written using femtosecond laser writing processes were used to write buried channel waveguides using compressive stresses to form the waveguide. These waveguides exhibited low-losses down to to 2.0 dB/cm in the telecommunications spectrum, with high coupling efficiency to SMF fiber, and excellent Raman properties in the waveguide core. These channel waveguides also successfully showed SRS generation into the 1.8-1.9 \mu m infrared region using a high power picosecond pump source in the telecommunications band. The use of the microreflectivity and micro-Raman spectroscopy measurement techniques were demonstrated to be valuable characterization tools for each of the fabrication methods.

The present thesis describes a novel photonic crystal platform dubbed the photonic nose, a color-based analogue of the human olfactory system. The platform is founded on a one dimensional photonic crystal architecture known as Bragg stacks, which are fabricated using bottom-up self-assembly approaches. Structural and compositional aspects of this novel class of photonic crystals are established that provide them with functionality and utility. Silicon dioxide, titanium dioxide, tin oxide, clays and zeolites are among the materials incorporated into one-dimensional photonic structures. Retention of materials functionality is demonstrated by vapor and liquid sensing experiments. This class of Bragg stacks displays well defined optical properties that have been thoroughly investigated by use of spectroscopic ellipsometry, as we demonstrate in a chapter dedicated to the technique. Utilizing conventional building blocks comprised of nanostructured silicon and titanium dioxide we discuss various aspects of technique pertaining single layered as well as multilayered films. In terms of practical applications these kinds of Bragg stacks show significant potential in areas such as display and sensors that exploit their vibrant and tunable colors. These colors are an important attribute of photonic crystals with bandgaps in the visible range and in this thesis work we present new approaches for characterizing photonic crystal color using well established methods from the field of color imagery. With this knowhow we have been able to assemble a pixilated array of chemically functionalized Bragg stacks in which each pixel responds differently to vapor phase analytes. The combinatorial response of the entire array enables a unique diagnostic fingerprint of a given analyte vapor as determined from color imagery and multivariate statistical methods of analysis. It was possible to discriminate between ethanol, butanol, hexanol, hexane, octane and decane. We also demonstrate the power of the photonic nose platform by distinguishing different bacteria from a photonic nose color analysis of the complex mixture of vapors in the bacteria culture headspace. Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis, and Pseudomonas aeruginosa could be discriminated based on this technique.