Nanoparticles (such as, carbon nanotubes, carbon black, clay etc.) have one or more dimensions of the order of 100 nm or less. Owing to very high van der Waals force of attraction, these nanoparticles exist in a highly aggregated state. It is often required to break these aggregates to truly experience the “nanosize” effect for any required end use. There are several strategies proposed for dispersing/exfoliating nanoparticles but limited progress has been made towards controlling their dispersion state. The ability to tailor nanoparticle dispersion state in liquid and solid media can ultimately provide a powerful method for tailoring the properties of solution processed nanoparticle-filled polymer composites. This dissertation reports the use of a variety of stimuli-responsive polymers to control the dispersion state of single-walled carbon nanotubes. Stimuli-responsive polymers exhibit conformational transitions as a function of applied stimulus (like pH, temp, chemical etc.). These variations in conformations of the polymer can be used tailor nanotube dispersion state in water and solid composites.The use of pH and temperature responsive polymers to stabilize/disperse single walled carbon nanotubes (SWNTs) in water is presented. Non-covalent functionalization of SWNTs using pH and temperature responsive polymer show tailored dispersion state as a function of pH and temperature, respectively. Carbon nanotube microstructure in these aqueous suspensions was characterized using several techniques (cryo-TEM, viscosity measurements, uv-vis spectroscopy, zeta potential measurements and settling behavior). Furthermore, nanotube dispersion state in aqueous suspensions is preserved to a large extent in the composites formed by drying these suspensions as evidenced by SEM images and electrical conductivity measurements. Based on the results obtained a mechanism is proposed to explain the tailored dispersion of SWNTs as a functions of applied external stimulus (i.e., pH, temperature). Such stimuli-controlled dispersion of carbon nanotubes could have a variety of applications in nanoelectronics, sensing, and drug and gene delivery systems. Furthermore, this dissertation also contains a published study focused on controlling the dispersion state of carbon black (CB) in epoxy composites using clay.

In this thesis, molecular dynamics and dissipative particle dynamics simulation methods are adopted to investigate the effects of volume fraction (1:1; 1:4; 1:6; 1:14; 1:20), repulsive interaction parameter (aij) and chain length on the microstructure of (5,5) carbon-nanotube (CNT)/polyethylene (PE) mixture. In order to obtain the information of microstructure for different simulation conditions, we used the radius of gyration and orientational order parameter to explore the polymer conformation. It is found that micro-structures will be very different when different repulsive interaction parameters and volume fractions are used.

In this dissertation, guided surface acoustic wave sensors were investigated theoretically and experimentally in detail for immunosensing applications. Shear horizontal polarized guided surface acoustic wave propagation for mass loading sensing applications was modeled using analytical modeling and characterized by perturbation analysis. The model verification was performed experimentally and a surface acoustic wave immunosensor case study was presented. The results of the immunosensing were also investigated using the perturbation analysis. Guided surface acoustic wave propagation problem was investigated in detail for gravimetric (or mass loading) guided wave sensors, more specifically for immunosensors. The analytical model was developed for multilayer systems taking viscoelasticity into account. The closed form algebraic solutions were obtained by applying appropriate boundary conditions. A numerical approach was used to solve dispersion equation. Detailed parametric investigation of dispersion curves was conducted using typical substrate materials and guiding layers. Substrate types of ST-cut quartz, 41° YX lithium Niobate and 36° YX lithium tantalate with guiding layers of silicon dioxide, metals (chromium and gold), and polymers (Parylene-C and SU-8) were investigated. The effects of frequency and degree of viscoelasticity were also studied. The results showed that frequency only has effect on thickness with same shaped dispersion curves. Dispersion curves were found to be unaffected by the degree of viscoelasticity. It was also observed that when there was a large shear velocity difference between substrate and guiding layer, a transition region with a gradual decrease in phase velocity was obtained. However, when shear velocities were close, a smooth transition was observed. Furthermore, it was observed that, large density differences between substrate and guiding layer resulted in sharp and with nearly constant slope transition. Smooth transition was observed for the cases of minimal density differences. Experimental verification of the model was done using multi-layer photoresists. It was shown that with modifications, the model was able to represent the cases studied. Perturbation equations were developed with first order approximations by relating the slope of the dispersion curves with sensitivity. The equations were used to investigate the sensitivity for material selection (substrate, guiding layer, and mass perturbing layer) and degree of viscoelasticity. The investigations showed that the sensitivity was increased by using guiding layers with lower shear velocities and densities. Among the guiding layers investigated, Parylene C showed the highest sensitivity followed by gold and chrome. The perturbation investigations were also extended to viscoelasticity and to protein layers for immunosensing applications. It was observed that, viscous behavior resulted in slightly higher sensitivity; and sensitivity to protein layers was very close to sensitivity for polymers. The optimum case is found to be ST-cut quartz with Parylene-C guiding layer for protein layer sensing. Finally, an immunosensing case study was presented for selective capture of protein B-cell lymphoma 2 (Bcl-2), which is elevated in many cancer types including ovarian cancer. The immunosensor was designed, fabricated, and experimentally characterized. An application-specific surface functionalization scheme with monoclonal antibodies, ODMS, Protein A/G and Pluronic F127 was developed and applied. Characterization was done using the oscillation frequency shift of with sensor used as the feedback element of an oscillator circuit. Detection of Bcl-2 with target sensitivity of 0.5 ng/ml from buffer solutions was presented. A linear relation between frequency shift and Bcl-2 concentration was observed. The selectivity was shown with experiments by introducing another protein, in addition to Bcl-2, to the buffer. It was seen that similar detection performance of Bcl-2 was obtained even with presence of control protein in very high concentrations. The results were also analyzed with perturbation equations.

Self-assembly of nanorods (NRs) enhanced by functionalization with liquid crystals (LC) ligands has been demonstrated. First, CTAB (cetyltrimethylammonium bromide) coated gold NRs were prepared in water through a modified one-step seed growth process. The hydrophilic GNRs were then converted into hydrophobic NRs employing a surface modification process using liquid crystalline organosilanes. The functionalized GNRs were characterized by TEM (transmission electron microscopy) and SAXS (small angle X-ray scattering) to investigate the packing mode of the GNRs. The results propose models of the assembly of the GNRs depending on nature and connectivity of the attached liquid crystal molecules. Furthermore, a macroscopic orientation of the GNRs doped in LC was achieved via an alignment technique of the liquid crystal host. SAXS analysis of the doped DLC indicated modification of lattice parameters due to the insertion of the DLC-GNRs, which resulted in an enhancement of the charge carrier mobility.

Pressing demands for high power and high energy densities in novel electrical energy storage units have caused reconsiderations regarding both the choice of battery chemistry and design. Practical concerns originating in the conventional use of flammable liquid electrolytes have renewed the interests of using solvent-free polymer electrolytes (SPEs) as solid ionic conductors for safer batteries. In this thesis work, SPEs developed from two polymer host structures, polyethers and polycarbonates, have been investigated for all-solid-state Li- and Li-ion battery applications. In the first part, functional polyether-based polymer electrolytes, such as poly(propylene glycol) triamine based oligomer and poly(propylene oxide)-based acrylates, were investigated for 3D-microbattery applications. The amine end-groups were favorable for forming conformal electrolyte coatings onto 3D electrodes via self-assembly. In-situ polymerization methods such as UV-initiated and electro-initiated polymerization techniques also showed potential to deposit uniform and conformal polymer coatings with thicknesses down to nano-dimensions. Moreover, poly(trimethylene carbonate) (PTMC), an alternative to the commonly investigated polyether host materials, was synthesized for SPE applications and showed promising functionality as battery electrolyte. High-molecular-weight PTMC was first applied in LiFePO4-based batteries. By incorporating an oligomeric PTMC as an interfacial mediator, enhanced surface contacts at the electrode/SPE interfaces and obvious improvements in initial capacities were realized. In addition, room-temperature functionality of PTMC-based SPEs was explored through copolymerization of ε-caprolactone (CL) with TMC. Stable cycling performance at ambient temperatures was confirmed in P(TMC/CL)-based LiFePO4 half cells (e.g., around 80 and 150 mAh g-1 at 22 °C and 40 °C under C/20 rate, respectively). Through functionalization, hydroxyl-capped PTMC demonstrated good surface adhesion to metal oxides and was applied on non-planar electrodes. Ionic transport behavior in polycarbonate-SPEs was examined by both experimental and computational approaches. A coupling of Li ion transport with the polymer chain motions was demonstrated. The final part of this work has been focused on exploring the key characteristics of the electrode/SPE interfacial chemistry using PEO and PTMC host materials, respectively. X-ray photoelectron spectroscopy (XPS) was used to get insights on the compositions of the interphase layers in both graphite and LiFePO4 half cells.

Despite the great abundance of C–H bonds in readily available starting materials, their use in synthesis of functionalized molecules has been hampered by the high bond strengths, rendering them inert to common organic reagents. However, recent progress in the field has addressed this issue, enabling selective C–H bond functionalizations to be performed using catalytic transition metal mediated processes. Herein, the use of sulfonyl chlorides as versatile reagents for C–H bond functionalizations is reported. Using chelation assistance, the regioselective conversion of C–H bonds to either C–S, C–Cl or C–C bonds was achieved. The methodology development, substrate scope determination and mechanistic investigations will be discussed.

Despite the great abundance of C–H bonds in readily available starting materials, their use in synthesis of functionalized molecules has been hampered by the high bond strengths, rendering them inert to common organic reagents. However, recent progress in the field has addressed this issue, enabling selective C–H bond functionalizations to be performed using catalytic transition metal mediated processes. Herein, the use of sulfonyl chlorides as versatile reagents for C–H bond functionalizations is reported. Using chelation assistance, the regioselective conversion of C–H bonds to either C–S, C–Cl or C–C bonds was achieved. The methodology development, substrate scope determination and mechanistic investigations will be discussed.

The field of metal-catalyzed C–H bond functionalizations is an incredibly vibrant and spans beyond the formations of biaryl motifs. The introduction chapter will cover the mechanistic aspects of the C–H bond functionalization with metal-carboxylate complexes. The mechanistic facets of this reaction will be the main conducting line between the different sections and chapters of the first part of this thesis. In the second chapter, will be described additives that can readily promoted C–H bond arylation of poorly reactive substrates. More specifically, we will revisit the intramolecular direct arylation reaction we will demonstrate the effect of pivalic acid as a co-catalyst by developing milder reaction conditions. In the third chapter we be described experimental and computational studies which suggested that the a single pathway might be involved in the palladium-catalyzed C–H bond functionalization of a wide range of (hetero)arene. Following this we will describe a general set of conditions for the direct arylation of wide range of heteroarenes. Also, we will present two different strategies to selectively and predictably arylate substrates containing multiple functionalizable C–H bonds. In the fourth chapter will be presented our efforts toward the development of new C–H bond functionalization methods in which we could apply our knowledge on the C–H bond cleavage and apply it to the formation of new scaffolds. The development of two new palladium-catalyzed methods were also described. In the fifth chapter, our effort toward the development of ligands to specifically promoted C–H bond cleavage will be presented. In the sixth chapter will be presented the latest results on the study of the mechanism of the C–H bond cleavage combining experimental and computational studies. In part B of this thesis will be presented our strategy toward the total synthesis of ginkgolide C that included two gold(I)-catalyzed reactions as key steps in the preparation of the spiro[4.4]nonane core of this natural product. The first studies on the feasibility of the key steps of the synthesis will be described.

La médecine moderne fait aujourd’hui face à de nombreux défis, comme le diagnostic précis et rapide des maladies. En raison de leurs propriétés photophysiques uniques, les quantum dots (QDs) sont des marqueurs fluorescents prometteurs pour la détection biologique. Le but principal de ce travail est le développement de conjuguées QD-anticorps (AB) en vue de leur utilisation dans des fluoroimmunoassays FRET (Förster Resonance Energy Transfer) pour la détection de la PSA (Antigène Spécifique de la Prostate), biomarqueur du cancer de la prostate. Dans ces systèmes, les QDs agissent comme accepteurs d’énergie en combinaison avec des complexes de terbium agissant comme donneurs. Grâce aux propriétés de luminescence spécifiques de ces deux classes de fluorophores, la mesure résolue en temps du signal de QDs permet la détection rapide et sensible des marqueurs biologiques. Nous avons développé une nouvelle approche en deux étapes pour la fonctionnalisation et la bioconjugaison de QDs qui donne des systèmes QD-AB fortement luminescents, stables et ultra compacts, maximisant ainsi l'efficacité de FRET. Dans une première étape, le transfert en phase aqueuse de QDs de phosphure d’indium (InP) synthétisés au laboratoire, émettant à 530 nm et de QDs commerciaux de CdSe émettant à 605 nm et 705 nm a été réalisé par échange de ligands de surface avec de la pénicillamine. Ensuite, la post-fonctionnalisation avec un ligand hétérobifonctionnel contenant un groupe acide lipoïque et une fonction maléimide permet le couplage ultérieur à des groupes sulfhydryle des protéines, a été effectuée. Après conjugaison des QDs avec des anticorps fragmentés (F(ab)) un très petit diamètre hydrodynamique (<13 nm) et une stabilité colloïdale à long terme (plusieurs années) ont été obtenus. L'applicabilité des sondes obtenues a été confirmée par la détection de PSA dans des échantillons de sérum, avec des limites de détection (LOD) très basses (0,8 ng/mL) pour les sondes émettant à 705 nm, dont l'absorption du spectre montre le plus grand recouvrement spectral avec l'émission du Tb. De plus, le greffage direct de complexes de terres rares sur la surface de QD a également été exploré, donnant accès à des sondes bimodales pour l'imagerie par resonance magnétique et par fluorescence (avec Gd) ou à des sondes biluminescentes (avec Eu, Yb). Dans ce dernier cas, la sensibilisation de la luminescence proche infrarouge de l’Yb par les QDs à base d’InP a été démontrée. Enfin nous avons réalisé des études de nanotoxicologie sur les différents types de QDs utilisés. En particulier, nous avons étudié la toxicité in vivo en utilisant l'organisme modèle Hydra vulgaris et la toxicité in vitro en utilisant des cellules de kératinocytes humains en comparant l’effet de systèmes cœur et cœur-coquille de QDs d’InP et de CdSe. / One of the many challenges modern medicine is facing today is the accurate and early diagnosis of diseases. Due to their unique photophysical properties semiconductor quantum dots (QDs) are promising fluorescent labels for biosensing. The major aim of this work is the development of QD antibody (AB) conjugates to be used in Förster resonance energy transfer (FRET) immunoassays for the detection of the tumor biomarker PSA (prostate specific antigen). In these assays, the QDs act as FRET acceptors in combination with terbium complex donors. Thanks to the specific luminescence properties of these two classes of fluorophores, time-gated detection of the QD signal allows for the fast and sensitive detection of biomarkers. We developed a novel two-step approach for QD functionalization and bioconjugation which yields ultra compact, stable and highly luminescent QD-AB conjugates maximizing FRET efficiency. In the first step aqueous phase transfer of lab-synthesized InP-based QDs emitting at 530 nm and of commercial CdSe-based QDs emitting at 605 nm and 705nm was achieved by surface ligand exchange with penicillamine. Then, post-functionalization with a heterobifunctional crosslinker, containing a lipoic acid group and a maleimide function, enabled the subsequent coupling to sulfhydryl groups of proteins. This was demonstrated by QD conjugation with fragmented antibodies (F(ab)); the obtained conjugates have a very low hydrodynamic diameter < 13 nm and long-term colloidal stability. The applicability of the obtained probes was confirmed by the detection of PSA in serum samples with detection limits (LODs) down to 0.8 ng/mL for the 705 nm emitting probes, whose absorption spectrum shows the largest overlap integral with the Tb emission. In addition, direct grafting of rare earth complexes on the QD surface has also been explored, giving access to dual-mode imaging agents (with Gd) or to biluminescent (with Eu, Yb) probes. In the latter case, the sensitization of Yb NIR luminescence by InP-based QDs has been firstly demonstrated. Finally, we carried out nanotoxicological studies on the different types of QDs used. In particular we investigated in vivo toxicity using the model organism Hydra Vulgaris and in vitro toxicity using human keratinocyte cells comparing core and core/shell InP-based and CdSe-based QDs.

In this dissertation, research efforts mainly focused on exploring the applications of superparamagnetic iron oxide nanoparticles (SPIONs) in MR imaging and nanocatalysis via surface functionalization. A dopamine-based surface-functionalization strategy was established. The Simanek dendrons (G1 to G3), oligonucleotides and amino acids were loaded onto SPION surfaces via this approach to develop pH-sensitive MRI contrast agents, specific-DNA MR probes and a biomimetic hydrolysis catalyst. Dendron-SPION conjugates (G1 to G3) have good aqueous solubilities and high transverse relaxivities (>300 s-1*mM-1). They also showed interesting strong pH-sensitive R2 and R2* relaxivities, which were governed by the clustering states of dendron-SPIONs in different pH environments. Values of R2m and R2* m/R2m varied by over an order of magnitude around pH 5. The efficient cell-uptake (~3 million/cell) and low cytotoxicity of G1 to G3-SPIONs were demonstrated on HeLa cell cultures. The strong R2* effects were observed indicating the SPION clustering in HeLa cells. Two SPION-oligonuleotide conjugates were synthesized by coupling two half-match oligonucleotides onto domapine-capped SPIONs via SPDP linkers. They served as MR probes to detect a single-strand DNA with the same sequence to miRNA-21 based on the change of R2 values due to the DNA-bridged SPION clustering. The detection limit of the DNA could reach to 16.5 nM. A biomimetic hydrolysis nanocatalyst (i.e., Fe2O3-Asp-His complex) was developed by loading Asp and His-dopamine derivatives onto SPIONs. Paraoxon and nitrophenyl acetate were hydrolyzed under a mild condition (neutral pH, 37 °C) catalyzed by the Fe2O3-Asp-His complex. The two amino acids Asp and His cooperated with each other on the SPION surfaces to catalyze hydrolysis reactions. This catalyst could be recycled by a magnet and reused for four times without a significant loss of catalytic activity.