Single molecule imaging has emerged as a powerful tool in a range of applications, but the field is limited by a lack of fluorescent probes with sufficient brightness and photostability for many demanding applications such as tracking of single biomolecules in cells and tissues at video rate with 1 nm spatial resolution. Conjugated polymers hold great promise as a solution to these issues, with a high density of pi electrons and variety of chemistries, allowing efficient and tunable absorption of light. This dissertation describes the development and characterization of a novel type of nanoparticle composed of conjugated polymer called CPdots. CPdots retain the high brightness of conjugated polymers in solution and in films, but can be dispersed in water, making them suitable for many biological applications. These CPdots have been shown to have one-photon absorptivities that range from 106 — 107 M-1 cm-1 (2-3 orders of magnitude higher than most other fluorescent dyes), and two-photon cross sections as high as 2 x 105 G.M. units (the highest reported value to date for a nanoparticle). A variety of complex photophysical phenomena were observed in CPdots, including complex photobleaching kinetics, reversible photobleaching, complex picosecond fluorescence kinetics, and collective excitation effects in single nanoparticles. A novel theoretical model describing the interactions between excitons and polarons in CPdots was developed. The model results predict complex photobleaching kinetics and complex picosecond fluorescence kinetics, in close agreement with experimental data. The model is also in qualitative agreement with many phenomena observed in fluorescence experiments performed on single nanoparticles. Gelation thermodynamics and kinetics of the conjugated polymer poly(2,5-dinonylparaphenylene ethynylene), which are important in film casting techniques, were investigated allowing the design of film casting methods that will yield specific energy transfer efficiencies. These investigations provide a thorough understanding of CPdot photophysics, necessary for the rational design of improved fluorescent probes. It is also hoped that the results of these investigations could help in understanding key processes that could limit efficiency of organic optoelectronic devices such as polymer-based light-emitting displays and polymer-based photovoltaic devices, and thus help in the development of strategies aimed at improving device efficiencies.

Phospholipid vesicles are biocompatible, and have potential for intracellular applications, but minimal membrane integrity limits their use in membrane-rich environments. Stabilized membranes overcome this limitation while maintaining biocompatible surface structures. Additionally, the modularity of phospholipid bilayer makes them ideal components when designing biologically inspired sensors. Membrane composition can be tailored to specific applications, transmembrane proteins can provide added functionalities, and the isolated interior can prevent cytotoxic and interfering detection chemistries from altering the cellular environment. This work has focused on expanding the capabilities of stabilized phospholipid membranes, and determining which formulations hold promise in developing stabilized phospholipid vesicle nanosensors. Current membrane stabilization methods suffer from either incomplete stabilization, or irreversible stabilization limiting the applications of vesicle nanosensors. Therefore, a facile method to prepare robust phospholipid vesicles using commonly available phospholipids stabilized via the formation of an interpenetrating, acid-labile, cross-linked polymer network that imparts controlled polymer destabilization and subsequent vesicle degradation was developed. Upon exposure to acidic conditions, the highly cross-linked polymer network was converted to linear polymers, substantially reducing vesicle stability upon exposure to chemical and physical insults. The resultant transiently stabilized vesicles have potential for enhanced drug delivery and chemical sensing applications requiring minimal membrane defects, and allow for improved physiological clearance. Some vesicle nanosensor schemes may require the passive diffusion of low molecular weight species across the membrane in addition to controllable degradation. Therefore, the acid-degradable, polymer-stabilized, phospholipid vesicle production method was extended to bis-SorbPC membranes by simultaneously polymerizing the vesicle with an acetal-containing cross-linker. The vesicles display prolonged stability under physiological conditions, and significant additional stability compared to vesicles composed of naturally occurring phospholipids. The vesicles demonstrated potential utility for sensing and therapeutic applications. Phospholipid vesicles can also serve as labels to observe movement in macromolecular biological assemblies, but a dearth of caged fluorescent labels limits design and function. Therefore, the first caged fluorescent thiol was synthesized, shown to label amines rapidly, and demonstrated the required photolytic properties. The caged fluorescent thiol has potential as a label in observing the movement of macromolecular biological assemblies and as a fluorescent probe for observing endosomal trafficking and release.

The majority of this dissertation focuses on proton conducting materials that could be used at high operating temperatures. Higher operating temperatures are desirable as they will increase fuel cell efficiency, reduce cost, and simplify the heat management system. The factors governing proton conduction including segmental mobility, protogenic group identity, and charge carrier density were investigated on a variety of polymers containing 1H -1,2,3-triazole moieties. Proton conductivity measurements were made using AC impedance spectroscopy. Random copolymers and terpolymers of triazole-containing acrylates and polyethylene glycol)methyl ether acrylate PEGMEA) have been synthesized. Conductivity increased with increasing degree of PEG incorporation until reaching a maximum at 30% mole PEGMEA. In comparison to benzimidazole-functionalized polyacrylate with 35% mole PEGMEA, the triazole analog showed a higher proton conductivity, and a less pronounced conductivity temperature dependence. Further increases in conductivity was achieved through the addition of trifluoroacetic acid. To study the effect of charge carrier density on proton conduction, polyacrylates containing a different number of triazole groups per repeat unit were synthesized. The result showed that introduction of more than one triazole per repeat unit did not result in an increase in conductivity as there was an accompanying increase in Tg. To improve the thermal and mechanical properties, triazole groups were tethered to a higher T g backbone polymer, polynorbornene. Introduction of polyhedral oligomeric silsesquioxane POSS) into triazole-functionalized polynorbornene was also investigated. In a parallel set of investigations, poly2-dimethylamino)ethyl methacrylate), PDMAEMA, and copolymers of DMAEMA and methyl methacrylate PDMAEMA-co-PMMA) were synthesized via atom transfer radical polymerization ATRP). Fluorescently-labeled PDMAEMAs were synthesized using fluorescent ATRP initiators to ensure the presence of one dye molecule on every polymer chain. PDMAEMAs and PDMAEMA-co-PMMA with different molecular weights have been deposited onto a negatively-charged silica surface via controlled flow deposition. The results show that the polymer deposition rate depends on molecular weight, and is inversely proportional to molecular weight. A preliminary adhesion study of 1-im negatively charged silica spheres onto these functionalized surfaces indicates that by varying the molecular weight, the adhesion threshold can be changed. System modeling is being conducted to support experimental observations.

The objectives of this study were to carry out research to better understand of the formation, stability and properties of multilayer emulsions containing nano-laminated biopolymer coatings, and to utilize this information to develop food-grade delivery systems. The effect of various preparation parameters on the formation and stability of multilayer emulsions was investigated: droplet concentration； mean droplet diameter； droplet charge； biopolymer concentration. beta-lactoglobulin beta-Lg) stabilized emulsions 0.5–10 wt% oil) containing different pectin concentrations 0 to 0.5 wt%) were prepared at pH 7 where lipid droplets and pectin molecules were both anionic) and pH 3.5 where lipid droplets were cationic and pectin molecules anionic) and “stability maps” were constructed. At pH 3.5, pectin adsorbed to the droplet surfaces, and the emulsions were unstable to bridging flocculation at intermediate pectin concentrations and unstable to depletion flocculation at high pectin concentrations. At certain droplet and pectin concentrations stable multilayer emulsions could be formed consisting of protein-coated lipid droplets surrounded by a pectin layer. An in situ electro-acoustic EA) technique was introduced to monitor the adsorption of charged polysaccharides onto oppositely charged protein-coated lipid droplets. The possibility of controlling interfacial and functional characteristics of multilayer emulsions by using mixed polysaccharides pectin/carrageenan or pectin/gum arabic) was then examined. Emulsions containing different types of polysaccharides had different interfacial characteristics and aggregation stabilities: carrageenan had the highest charge density and affinity for the protein-coated lipid droplets, but gave the poorest emulsion stability. The possibility of assembling protein-rich coatings around lipid droplets was examined using the electrostatic deposition method, with the aim of producing emulsions with novel functionality. Protein-rich biopolymer coatings consisting of beta-Lg and pectin were formed around lipid droplets using the electrostatic deposition method. The composite particles formed had relatively small diameters d &lt； 500 nm) and were stable to gravitational separation. They also remained stable after they were heated above the thermal denaturation temperature of the globular protein and had better stability to aggregation at high salt concentrations 50–200 mM NaCl) than conventional emulsions stabilized by only protein. The effect of a polysaccharide coating on the displacement of adsorbed globular proteins by non-ionic surfactants from lipid droplet surfaces was examined to simulate situations where competitive adsorption occurs. Oil-in-water emulsions stabilized by beta-Lg were prepared containing either no pectin 1&deg； emulsions) or different amounts of pectin 2&deg； emulsions). At pH 3.5, where pectin forms a coating around the beta-Lg stabilized lipid droplets, the amount of desorbed protein was much less for the 2&deg； emulsion 3%) than for the 1&deg； emulsion 39%), which indicated that the pectin coating inhibited protein desorption by surface active agents. Knowledge gained from this research will provide guidelines for rationally designing emulsion-based delivery systems that are resistant to environmental stresses or with controlled release properties. These delivery systems could be used to encapsulate, protect and release functional components in various industrial products, such as foods, pharmaceuticals, cosmetics, and personal care products.

In recent years scientific and technological advancements have been made in the research and development of controlled drug delivery systems and new chemopreventive agents. For many potential drug candidates a modified in vivo drug release is desired to improve efficacy, sustain drug effect or minimize drug toxicity. To tackle the problems associated with the delivery of drug, delivery systems DDS) with multiple functionalities such as environment-sensitive drug release mechanisms have motivated the biomedical community as well as materials chemists for more than a decade. Polymeric drug delivery systems have been extensively studied in an attempt to achieve modified drug release. Here we report on a novel thermo-responsive based system to fabricate biocompatible polymeric hydrogels as drug delivery as well as the development of a new class of non-steroidal anti-inflammatory drugs as chemopreventive agents. Biocompatible Pluronic F127 PF127), a triblock copolymer, was employed as matrix materials for polymeric-based DDS. This thermo-sensitive polymeric system have been modified by acrylation and cross-linked to form a hydrogel based drug delivery system. The modified polymeric system contains a hydrophobic polypropylene oxide PPO) and a hydrophilic polyethylene oxide PEO) blocks which undergoes a “hydrophilic-hydrophobic” phase transition in aqueous media and around the human body temperature. In addition, poly lactic-co-glycolic acid PLGA) nanoparticles were assembled by solvent extraction method and incorporated in the modified Pluronic F127 hydrogels as drug carrier units. These modifications of PF127 were monitored by 1H-NMR and rheological studies. The rheological study determined that the degree of cross-linking affect the release rate of the drug from the PF127/PLGA system. The control release rate of the chemopreventive compounds seems to be further enhanced due to the addition of the PLGA nanoparticles. The in vitro cellular uptake and the cytotoxicity studies of the PLGA nanoparticles have been considered to determine their enhancement of drug uptake and the lack of acute cytotoxicity. The sensitivity of the polymer to the temperature was shown to facilitate drug release upon administered temperature changes. This work also focuses on the development and analysis of non-steroidal anti-inflammatory drugs NSAIDs) as chemopreventive agents. NSAIDs are a class of drugs that are commonly used as medications because of their pain- and fever reducing properties. Several chemopreventive studies have reported that NSAIDs and their derivatives have potential promise as anticancer agents. Based on pharmaco-kinetics, pharmaco-dynamic and structure activity relationship studies performed in this work, a new series of NSAID derivatives have been designed and synthesized. In vitro evaluation showed that these new generations of NSAIDs exhibit higher potency than that of traditional NSAIDs such as aspirin, especially against pancreatic and colon cancer. One of two NSAIDs hydrophobic model drugs, sulindac sulfide or Drug D was loaded in the modified Pluronic F127/PLGA drug delivery system. The NSAIDs have been shown to be successfully release from the modified PF217/PLGA drug delivery system applied both media and cell culture. This property can find application in externally stimulated drug release applications at the site of the disease. The studies performed in this dissertation to analysis, design and synthesize the old and new generations of NSAIDs was a collaborative effort of many persons. I performed the majority of the analysis and manuscript workings after the NSAIDs were synthesized and animals were treated and sacrifice by other collaborators. All studies in regards to the construct and design of the PF127/PLGA drug delivery system were done under the guidance or Prof. Miriam Rafailovich and Dr. Basil Rigas.

Three ionic liquids (ILs), trihexyltetradecylphosphonium tetrafluoroborate (TTPT), N-butyl-4-methylpyridinium tetrafluoroborate (BMPT), and 1-methyl-3-octylimidazolium tetrafluoroborate (MOIC), were utilized to prepare sol-gel sorbent coatings. Non-polar polydimethylsiloxane (PDMS) and polar poly(ethylene glycol) (PEG), poly(tetrahydrofuran) (PolyTHF) and bis[(3-methyldimethoxy-silyl)propyl] polypropylene oxide (BMPO) polymers were employed to develop novel ionic liquid-mediated sol-gel hybrid organic-inorganic sorbents. The novel sorbents were first tested as coatings for capillary microextraction off-line hyphenated to gas chromatography. To gain an understanding of the role of the ionic liquids in the sol-gel process, the preconcentration abilities of these novel coatings were investigated for several classes of compounds utilizing CME-GC. This was accomplished by comparing GC peak areas of a series of analytes extracted on the ionic liquid mediated sol-gel CME coatings with that of analogous peak areas obtained on sol-gel coatings prepared without the ionic liquid. The morphology of these coatings was compared using scanning electron microscopy (SEM) imaging data. Overall, the ionic liquid-mediated sol-gel coatings had more porous morphologies than the sol-gel coatings prepared without ionic liquid. The PDMS and BMPO sol-gel coatings prepared with ionic liquid in the sol solution provided enhanced extraction sensitivity reflected in higher preconcentration effects and lower detection limits than the sol-gel coatings prepared without the ionic liquid. The polar IL-mediated BMPO sol-gel sorbent was further investigated by exploring the extraction profile and thermal stability of these coatings. A further application of ionic liquid-mediated sol-gel sorbents could be as stationary phases in a microchip-based separation system. Towards this goal, microfluidic channels were fabricated in glass substrates using microelectromechanical engineering. Spiral and serpentine channels were etched in Pyrex and fused silica wafers using wet and deep reactive ion etching (DRIE) techniques. Microfabrication protocols such as the use of hard mask and etching times were investigated for both techniques. DRIE produced microfluidic channels that had an etch quality that was superior to wet etched channels. Thus, the ultimate microchip-based separation system should by fabricated using DRIE.

Amphiphilic hydrogels with different molecular architecture were successfully synthesized by two methods: 1) Williamson ether synthesis with linear or hyperbranched poly [p-chloromethyl) styrene], PPCMSt and polyethylene glycol), PEG, and 2) nucleophilic substitution reaction between PPCMSt and polyoxyalkylene) diamine, Jeffamine. Highly porous networks were achieved, as confirmed by scanning electron microscopy SEM), exhibiting high swelling ratio in both water and organic solvents. Dynamic swelling studies showed that the networks absorb water quickly and reach equilibrium in 1-3 hours. Reactive amphiphilic hydrogels with covalently bonded drugs were prepared by the same methods using the drug modified PPCMSt. Preliminary drug release study using model compounds demonstrated the kinetics of drug release in terms of the physical properties of drugs, the microstrucutre of polymer matrix, the drug-polymer interaction, and more particularly, the hydrolysis of ester linkage between the drug and polymer. Furthermore, original nanoparticles consisting of a hydrophobic core PPCMSt), linked with a biocompatible hydrophilic shell PEG), were prepared in aqueous media by self-assembly of comb and star-like amphiphilic block copolymers. These two copolymers were synthesized by grafting the alkyne mono-terminated PEG chains with different molecular weight to the linear PPCMSt backbone or hyperbranched PPCMSt via Huisgen cycloaddition. The physical properties of block copolymers were controlled by the nature of the two building blocks, the architecture of macromolecules, and the molecular weight of PEG. By modification of the surface functionalities with various compounds, these nanoparticles can be developed to serve as unique drug-delivery vehicles that have the ability to respond to ambient changes including pH and temperature. Key words. hyperbranched polymer, amphiphilic hydrogel, swelling, morphology, block copolymer, micelle, click chemistry.

This thesis is divided in two parts, as it deals with two main research areas. The first part describes experiments that examine the role of the morphology on the mechanical properties of polymer composite films, whereas the second part deals with the controlled self-assembly of polymer-tethered gold nanorods. For the first part of this thesis, core-shell latex particles were synthesized comprising high-glass transition temperature cores and low-glass transition temperature shells. From the latex particles, two types of composite films were prepared. One type of films featured a regular distribution of hard inclusions in a soft, elastomeric matrix, whereas the other type of film featured a more random distribution of the hard inclusions in the matrix. The mechanical properties of the two types of film were measured and compared at various test rates and temperature. The influence of the film morphology was extracted. At room temperature, the films with a random distribution of the hard particles showed higher hardness and stiffness than the films with an ordered distribution of the particles. At high temperature, the mechanical properties of the two types of film were comparable. In the second part of the thesis, gold nanorods were functionalized through the selective attachment of either polystyrene or polyN-isopropyl acrylamide) chains to their short facets. The polystyrene-modified gold nanorods were self-assembled into various structures in ternary mixtures of DMF/THF/water, by changing the ratio of the solvents in the mixtures. The polyN-isopropyl acrylamide)-modified gold nanorods were reversibly self-assembled into chains in water, by increasing the temperature of their water solution to above 33&deg；C. To our knowledge this is the first example of temperature-driven self-assembly of inorganic nanorods.

The overall objective of this work was to synthetize and to characterize polymers that are able to self-assemble in aqueous solution in response to an external trigger. To achieve this goal, we concentrated our efforts on two polymers, poly2-isopropyl-2-oxazoline) PiPrOx and poly2-ethyl-2-oxazoline) PEtOx derivatives. Hydrophobically end-modified HM) poly2-alkyl-2-oxazoline)s HM-PAkOx), AkOx ＝ 2-ethyl-2-oxazoline and 2-isopropyl-2-oxazoline, bearing an n-C18H37 chain on both termini telechelic HM-PiPrOx) or on one chain end only semitelechelic HM-PiPrOx) were prepared by cationic ring-opening polymerization CROP) of 2-alkyl-2-oxazoline and subsequent end-group modification. The polymers had a molar mass Mn) ranging from 7,000 to 13,000 g mol-1. Most of them formed nanostructures RH &sim； 7 — 12 nm) in cold water, as demonstrated by SLS, DLS, SAXS, 1 H NMR spectroscopy and fluorescence spectroscopy measurements carried out with aqueous solutions of telechelic and semitelechelic HM-PAkOx. As HM-PiPrOx aqueous solutions are heated near their cloud point, intermicellar bridging takes place leading to the formation of large assemblies or hydrated microgels. Further heating of the solutions to the lower critical solution temperature LCST) of PAkOx caused the dehydration of the polymer chains and collapse of the microgels, leading to mesoglogule formation. The thermodynamic properties of polymers in water have been studied by microcalorimetry DSC and PPC) in order to assess the influence of the molecular weight of the polymers, and of their self-assemblies into micelles star or flower micelles). Transition temperatures, enthalpy of transition, thermal expansion coefficient, changes in the volume of the hydration layer of the polymer in H2O and D2O were determined for all polymers. Moreover, it was shown that semitelechelic HM-PiPrOx crystallized upon incubation in hot water, whereas telechelic HM-PiPrOx do not exhibit this property. Furthermore, the self-assembly of the HM-polymers at the A/W interface was studied by the Langmuir film method. The influence of the molecular weight, the spreading solution concentration and the water subphase temperature on the interfacial properties of HM-polymers was evaluated. By Brewster angle microscopy BAM) and by atomic force microscopy AFM) observation, it was established that HM-PiPrOx polymers form large domains 400 nm — 1 mum in diameter) at the interface rather than homogenous films. Keywords: Poly2-isopropyl-2-oxazoline), poly2-ethyl-2-oxazoline), Lower critical solution temperature LCST), amphiphilic polymers, telechelic polymers, micelles, microcalorimetry, light scattering, air/water interface.

With the inevitable depletion of petroleum-based resources, there has been an increasing worldwide interest in renewable resources such as biomass. One reason for the current approaches being taken to utilize biomass is the difficulty in processing lignocellulosic materials and the energy needed for separation of the components. The three major components of biomass are covalently bonded together, which makes dissolution and further separation of the three major components difficult and this has been recognized as the grand challenge for biomass utilization. This dissertation describes research efforts in processing of lignocellulosic biomass using ionic liquids ILs) as solvents. ILs are salts with melting points below 100&deg；C, which possess many advantage properties. Cellulose composite fibers have been prepared based on IL solution with dispersion of the additives. Wood and bagasse have been completely dissolved in ILs. Partial separation of the components has been obtained using selected reconstitution solvents. High temperature and fast dissolution was found to be an efficient method for both dissolution and separation of biomass components. Biomass composite fibers can be prepared directly from such biomass solutions. With selected catalysts in solution, improved dissolution and separation has been achieved, making the delignification and pulp yield comparable to the kraft pulping process.