http://hdl.handle.net/1974/790 2013-05-23T03:13:49Z http://hdl.handle.net/1974/7983 Title: Design, Synthesis, and Application of Stimuli-Responsive Block Copolymers Authors: Rabnawaz, MUHAMMAD Abstract: This thesis reports the preparation of novel multi-responsive and multiply stimulable triblock copolymers. The resultant polymers were used to coat cotton fabrics and glass to render them amphiphobic. Further, a method was developed for the preparation of poly(ethylene glycol)-block-poly(hydroxyethyl methacrylate) (PEG-b-PHEMA) via anionic polymerization. The multi-responsive copolymer refers to poly(ethylene glycol)-orthonitrobenzyl-poly[2-(perfluorooctyl)ethyl methacrylate)-block-poly(2-cinnamoloxyethyl methacrylate) (PEG-ONB-PFOEMA-b-PCEMA, or P1). P1 was synthesized via atom transfer radical polymerization (ATRP) of FOEMA and a precursory monomer of CEMA using a PEG macroinitiator. The copolymer was multi-responsive or dual light-responsive because the ONB junction cleaves and PCEMA block becomes crosslinked upon UV photolysis. The multiply stimulable copolymers are a series of poly(ethylene glycol)-disulfide-poly[2-(perfluorooctyl)ethyl methacrylate)-block-poly(2-cinnamoloxyethyl methacrylate) (PEG-S2-PFOEMA-b-PCEMA) copolymers. These polymers were synthesized by the end-coupling Py-S2-PFOEMA-b-PHEMA and PEG-SH, and subsequent cinnamation of the PHEMA block. These polymers are multiply stimulable because the S2 junction and PCEMA block respond to different stimulations, such as reducing agents and light, respectively. These synthetic strategies will advance the field of stimuli-responsive polymers by providing novel functional polymers for the generation of durable self-cleaning surfaces. The above polymers form micelles in water or water/organic solvent mixtures because of the water-soluble PEG blocks. Polymer-coated cotton was obtained by immersing cotton in micellar copolymer solutions before subsequent drying and annealing treatment. Upon photolysis, the PEG block was cleaved and the PCEMA anchoring layer became crosslinked. Such a crosslinked and stable layer was rendered amphiphobic because of the exposed PFOEMA block. A similar coating can be obtained from P2. Two types of stimulations including photolysis and reduction treatment need to be applied to yield amphiphobic textiles. This coating strategy is unique and environmentally friendly because the water- and oil-repellent coatings were prepared from an aqueous solution for the first time. In a further study, a novel and long-sought method was developed for the anionic polymerization of PEG-b-PHEMA. A PEG-DPE macroinitiator was synthesized and subsequently converted into an active initiator by reaction with sec-butyl lithium. Consequently, the active initiator underwent polymerization with HEMA-TMS to yield PEG-b-P(HEMA-TMS). Upon post-polymerization modification, PEG-b-PHEMA was obtained with a low polydispersity of 1.08. Description: Thesis (Ph.D, Chemistry) -- Queen's University, 2013-04-29 12:25:54.593 2013-04-29T04:00:00Z http://hdl.handle.net/1974/7921 Title: QUALITY AND DURABILITY OF RUBBERIZED ASPHALT CEMENT AND WARM RUBBERIZED ASPHALT CEMENT Authors: ADHIKARI, THAM Abstract: This thesis discusses and documents findings from an investigation of performance-based testing of asphalt cement (AC), warm mixed asphalt cement, asphalt rubber (AR), and warm asphalt rubber. A number of control, warm, and asphalt rubber binders from Ontario construction contracts were investigated for their compliance with conventional Superpave® test methods such as rolling thin film (RTFO), pressure aging vessel (PAV), dynamic shear rheometer (DSR), and bending beam rheometer (BBR), as well as additional specification tests such as extended BBR and double edge notched tension test. The quality and durability of those binders were determined. Quality means the ability of asphalt binder to reach a set of specific properties whereas durability is the measure of how well asphalt retains its original characteristics when exposed to normal weathering and aging process. One warm AC and two field-blended asphalt rubber samples showed high levels of physical hardening which can lead to premature and early cracking. The warm asphalt cement lost 8 °C when stored isothermally for three days at low temperatures according to Ontario’s extended bending beam rheometer (BBR) protocol (LS-308). The two asphalt rubber samples lost 10 °C and 12 °C following the same conditioning. Many of the studied asphalt samples showed deficient strain tolerance as measured in Ontario’s double-edge-notched tension (DENT) test (LS-299). In a study of warm rubberized asphalt cement with improved properties, a number of compositions were prepared with soft Cold Lake AC and a small quantity of naphthenic oil. These binders showed little chemical and physical hardening and reasonable critical crack tip opening displacements (CTOD). Strain tolerance was much improved by co-blending with a high vinyl type styrene-butadiene-styrene (SBS) polymer and a small amount of sulfur. Description: Thesis (Master, Chemistry) -- Queen's University, 2013-04-24 22:54:20.07 2013-04-25T04:00:00Z http://hdl.handle.net/1974/7913 Title: N^N- AND N^C CHELATE FOUR-COORDINATE ORGANOBORON COMPOUNDS: SYNTHESIS, PROPERTIES AND APPLICATIONS Authors: Lu, JIASHENG Abstract: This thesis concerns the synthesis of N^N- and N^C-chelate four coordinate organoboron compounds and the investigation of their photophysical and photochemical properties. The preparation of a novel BODIPY derivative possessing unusual dual emissive property has been accomplished. The origin of the dual emission was determined through a detailed investigation. The use of the new BODIPY compound as a highly effective surface ligand for achieving highly uniform and monodispersed PbS nanoparticles has been demonstrated. Electronic communication between BODIPY ligands at the nanoparticle surface and the PbS core has also been established. The incorporation of BODIPY-bearing PbS nanoparticles into a simple photovoltaic device was shown to enhance the device’s performance. The preparation of two new BODIPY molecules decorated with either BMes2(vinyl) units or N^C-chelate boryl units has been achieved. Substitution at the meso or the 2,6-positions of the BODIPY core resulted in a significant shift of the emission energy with respect to that of the parent compound. In contrast, replacement of the fluorine substituents with BMes2-vinyl or B(ppy)Mes2-alkynyl groups did not affect the emission wavelength. Both molecules exhibited excellent photophysical properties in solution and the solid state. The BMes2(vinyl) unit greatly enhances BODIPY fluorescence efficiency in a PMMA matrix. Meanwhile, the photoreactivity of the N^C-chelate boryl unit is switched off completely by the BODIPY ligand via intramolecular energy transfer. A new class of N^C-chelate organoboron compounds have been synthesized. This class of compounds has been found to display unprecedented photo-reactivity, namely, photo-elimination reactions, which enabled the synthesis of new B-N substituted phenanthrene compounds in high conversion yields. The new B-N substituted phenanthrene compounds exhibited excellent absorptive and emissive properties with potential applications in optoelectronic devices. Description: Thesis (Ph.D, Chemistry) -- Queen's University, 2013-04-22 15:53:14.091 2013-04-24T04:00:00Z http://hdl.handle.net/1974/7906 Title: Fibre-Loop Ring-Down Spectroscopy Using Liquid Core Waveguides Authors: Bescherer-Nachtmann, Klaus Abstract: Cavity ring-down spectroscopy has been used over the last twenty years as a highly sensitive absorption spectroscopic technique to measure light attenuation in gases, liquids, and solid samples. An optical cavity is used as a multi-pass cell, and the decay time of the light intensity in the cavity is measured, thereby rendering the techniques insensitive to light intensity fluctuations. Optical waveguides are used to build the optical cavities presented in this work. The geometries of such waveguides permit the use of very small liquid sample volumes while retaining the advantages of cavity ring-down spectroscopy. In this thesis cavity ring-down measurements are conducted, both, in the time domain and by measuring phase-shifts of sinusoidally modulated light, and the two methods are theoretically connected using a simple mathematical model, which is then experimentally confirmed. A new laser driver, that is compatible with high powered diode lasers, has to be designed to be able to switch from time domain to frequency domain measurements. A sample path length enhancement within the optical cavity is explored with the use of liquid core waveguides. The setup was optimised with respect to the matrix liquid, the geometrical matching of waveguide geometries, and the shape of liquid core waveguide ends. Additionally, a new technique of producing concave lenses at fibre ends has been developed and the output of a general fibre lens is simulated. Finally, liquid core waveguides are incorporated into a fibre-loop ring-down spectroscopy setup to measure the attenuation of two model dyes in a sample volume of <1 µL. The setup is characterized by measuring concentrations of Allura Red AC and Congo Red from 1 µM to a limit of detection of 5 nM. The performance of the setup is compared to other absorption techniques measuring liquid samples. Description: Thesis (Ph.D, Chemistry) -- Queen's University, 2013-04-23 14:08:16.33 2013-04-23T04:00:00Z