Dissertationen zum Thema „Self-assembly in water“

The work presented is a continuation of the study of a homologous series of tetrabutylammonium perfluoroalkylcarboxylate surfactants in water. These systems showed phase behaviour uncharacteristic of ionic perfluorocarbon surfactant systems in that they exhibit a clouding phenomenon with increasing temperature. This behaviour was ascribed to the tight association of the large, hydrophobic counterions with the poiar head group region. In this study a series of perfluorocarbon surfactants have been synthesised in which the hycirophobicity of the counterion is varied. The counterion is W (CH2CH2CH2CH3)(CH3) 41 whilst the surfactant ion remains unchanged throughout the series as periluorodecanoate. The number of butyl chains. 'n' controls the hydrophobicity of the counterion and, in these experiments, n = 4, 2, 1 and 0. The phase diagrams and the detailed phase structures have been investigated using optical polarising microscopy, 2H NMR spectroscopy and small angle x-ray scattering. As n decreases, the phase diagrams change, recovering the "generic" phase behaviour more usual for a perfluorocarbon surfactant - water system. X-ray measurements show that in the n = 4 (tetrabutylammonium perfluorodecanoate) system, all the phases (both liquid crystalline and non-liquid crystalline) have uniform mean interfacial curvature. The phases observed are L 1 (vesicles), L. and L 2. With decreasing counterion hydrophobicity, the population of counterions associated with the interface decreases, introducing greater curvature into the system. The mean curvature of the phase structures also becomes nonuniform. For n = 0 (tetramethylammonium perfluorodecarioate) no classical mesophases are observed. Much of the liquid crystalline region is taken up with a random mesh intermediate phase, Mh 1 (0) and an extensive rhombohedral mesh intermediate phase, Mh1 (R3 m). Phase behaviour intermediate between the two extremes is observed at n = 1 (butyltrimethylammonium perfluorodecanoate). In this system, the clouding phenomenon is not observed but there is a two phase region of L 1 + L. at low concentration and high temperatures. The phase structures also possess uniform mean curvature. In keeping with the less hydrophobic systems, the L. phase is less temperature sensitive at high concentrations. This work has shown that the but'l groups of the counterion are, in part, responsible for the unusual phase behaviour observed in the TBA surfactants. The hydrophobic nature of the counterion has a major impact on the structures formed even at high dilution. This nature probably drives the counterion to the interface which affects the type of mesophase formed at higher concentrations and also determines its stability with respect to temperature and concentration.

Two-dimensional (2D) colloidal materials and their assembly are of scientific significance and industrial importance. The development of 2D colloidal structures is a key stepping stone towards three-dimensional (3D) structures in relation to controlled chemical composition, morphology, assembly and so on. Nowadays, uniform colloidal structures with complexity in both shape and interactions have become a popular topic in fundamental colloid science and applications. Being motivated by this, in this thesis, micro-scale colloidal rods and self-assembled dipeptides have been studied experimentally at the air-water interface. Monolayers containing these colloidal materials were created in a Langmuir trough. Surface pressure measurements, microscopic observations and many other techniques were combined for the investigation. The aim of this work is to understand the phase behaviours in complex monolayers, including the phase transitions during compression, the flipping dynamics of micro-rods, the contribution of dipole-dipole interactions between magnetic rods, and the interfacial self-assembly process of dipeptide molecules. Iron oxide micro-rods (β-FeOOH @silica) with different aspect ratios have been synthesized to create the monolayers at an air-water interface. Microscopic observations reveal a sequence of phase transitions by compressing the monolayers. It has been proved that the aspect ratio of the rods plays an important role in the phase transitions, —short rods flip into a perpendicular position relative to the interface to relieve the compressional stress, while longer rods form multilayers under compression. Magnetic rods (Fe3O4) were converted from the synthesized FeOOH rods. They can be aligned in an external field, which further induces the reorganization at the interface. To study these magnetic rods, differential dynamic microscopy (DDM) was carried out to measure the magnetic moment. Their interfacial properties were investigated in an external field applied perpendicular and parallel to the interface, respectively. A magnetic field-induced flipping process has been observed, which proves the theoretical prediction. Besides rod-like particles, naphthalene dipeptides have been successfully trapped at the interface of a low pH subphase, self-assembling into a hydrogel film. The mechanism of interfacial self-assembly has been studied. Both FTIR spectra and AFM images are used to investigate the fibrous structures of the film. The film has elastic properties and buckles under compression. Moreover, dipeptide hydrogel induced by metal ions has been used to create a wet foam system, which owns the advantages of long-term stability (more than two weeks), low cost, and easy preparation.

Conformational stability of the collagen triple helix affects its turnover and determines tissue homeostasis. Although it is known that the presence of imino acids (prolines or hydroxyprolines) confer stability to the molecule, little is known regarding the stability of the imino-poor region lacking imino acids, which plays a key role in collagen cleavage. In particular, there have been continuing debates about the role of water in collagen stability. We addressed these issues using molecular dynamics simulations on 30-residue long collagen triple helices, including a structure that has a biologically relevant 9-residue imino-poor region from type III collagen (Protein Data Bank ID: 1BKV). We characterized the conformational motion of the molecule that differs between imino-rich and imino-poor regions using a torsional map approach. At temperatures of 300 K and above, unwinding initiates at a common cleavage site, the glycine-isoleucine bond in the imino-poor region. This provides a linkage between previous observations that unwinding of the imino-poor region is a requirement for collagenase cleavage, and that isolated collagen molecules are unstable at body temperature. Unwinding of the imino-poor region is controlled by dynamic water bridges between backbone atoms with average lifetimes on the order of a few picoseconds, as the degree of unwinding strongly correlated with the loss of water bridges, and unwinding could be either prevented or enhanced, respectively by enforcing or forbidding water bridge formation. While individual water bridges were short-lived in the imino-poor region, the hydration shell surrounding the entire molecule was stable even at 330 K. The diameter of the hydrated collagen including the first hydration shell was about 14 Â, in good agreement with the experimentally measured inter-collagen distances. These results elucidate the general role of water in collagen turnover: water not only affects collagen cleavage by controlling its torsional motion, but it also forms a larger-scale lubrication layer mediating collagen self-assembly.

The objective of this work is to develop synthetic methodology for self-assembling and water-soluble imidazole-containing porphyrinic molecules. The synthesis of the following types of compounds is described: (1) Imidazole-containing porphyrinic compounds; (2) Derivatization of the imidazolyl porphyrins to obtain water-soluble imidazolium porphyrins, and (3) Improved synthesis of tetrahydrodipyrrins - a precursor of hydroporphyrins. The self-assembly of imidazolyl metalloporphyrins was examined by UV-VIS spectroscopic analysis. Each imidazoyl metalloporphyrin was found to aggregate in non-polar solvents such as CH2Cl2. The test of water solubility was also based on absorption spectroscopy. A refined synthesis of a tetrahydrodipyrrin is described for medium-scale synthesis (>10 g of the product), which facilitates access to diverse hydroporphyrins. Water-soluble porphyrinic molecules are useful for life sciences applications, and the tetrahydrodipyrrin precursors are important for the synthesis of a variety of hydroporphyrins. Taken together, this work advances the methodology for preparing a variety of synthetic porphyrins.

18-methyl eicosanoic acid (18-MEA), which is a branched fatty acid, is found at the outermost surface of mammalian hair with other straight-chain fatty acids such as palmitic acid and stearic acid. However, the precise role of 18-MEA is not yet completely understood. 18-MEA on Cadmium chloride subphase forms curvature at the water/air interface, leading to the formation of 3D-domains that can be easily transferred into solid support allowing to create complex and multi-functional structures. This project investigates if a non-toxic subphase would also lead to the formation of 3D-domains or if it is an intrinsic property of Cadmium chloride; and to investigate if the domain properties were tuneable. A combination of the Langmuir trough and the Atomic Force Microscopy is used. It is shown that a toxic subphase is not necessary and a more benign sodium subphase can be used to obtain 3D-domains. It is also shown that different chains length interact dissimilarly with the branched fatty acid. This results in the formation of very various structures. It is also shown that the subphase, the surface pressure of deposition and the composition of the fatty acid in the monolayer affect the properties of the domain, leading to different size of domain but also different morphology in the domain. Circular domains, elongated domains, continuous labyrinthine structures, dendritic centipede-like structures and no domains are obtained.
På den yttersta ytan av däggdjurshår återfinns den grenade fettsyran 18-methyleikosansyra tillsammans en mindre mängd av de raka fettsyrornapalmitinsyra och stearinsyra. Den exakta rollen av 18-MEA är dock ännu inte heltklarlagd. Ett monoskikt av 18-MEA på en subfas innehållande kadmiumklorid påtvingar en krökning av vatten–luftgränsytan. Det leder till bildandet av 3D-domäner som lätt kan överföras från vattenytan till fasta ytor vilket möjliggör att dekorera dessa ytor med komplexa och multifunktionella strukturer. Detta projekt undersöker om andra, miljövänliga motjoner i subfasen också skulle leda till bildandet av 3D-domäner eller om det är en inneboende egenskap hos kadmiumklorid. Det här ger även insikt om hur motjoner kan användas för att påverka och kontrollera domänbildningen. En kombination av Langmuirtråg och atomkraftsmikroskopi används för att karakterisera monoskikten. Det visas att en subfas innehållande kadmium inte är nödvändig och att en mer miljövänlig natriumsubfas kan användas för att bilda 3D-domäner. Det visas också att olika kedjors längd interagerar olika med den grenade fettsyran 18-MEA, vilket resulterar i bildandet av olika strukturer i deponerade monoskikt. Det visas också att yttrycket vid deponering och sammansättningen av fettsyror i mono skiktet påverkar egenskaperna hos monoskiktet, vilket leder till varierande storlek och struktur på de bildade domänerna, där cirkulära och långsträckta domäner, kontinuerliga labyrintstrukturer och dendritiska tusenfotingsliknande strukturer observeras.

This thesis discusses progress made towards assembling molecular building blocks in the presence of our molecular host of choice, cucurbit[8]uril (CB[8]). Our studies on the self-assembly of synthetic and biological components in water bridge overlapping conceptsand techniques drawn from the fields of synthetic organic chemistry, supramolecular self-assembly, and applied NMR techniques. Chapter 1 introduces the reader to chemical complexity, and how supramolecular chemistshave advanced in their capability of assembling more complex molecular architectures. The discussion focusses particularly on self-assembly carried out in the aqueousphase, and how, like in biology, molecular design of the building blocks become criticalin enabling non-covalent assembly to occur in this dynamic, and relatively competitiveenvironment. The cucurbit[n]uril family of molecular hosts are then introduced with anoverview of their modes of binding, and affinities towards typical guests. Finally, a practicalintroduction to NMR methods gaining prominence in supramolecular chemistry ispresented. In particular, the use of diffusion NMR, a key tool for probing the solutiondynamics of molecular assemblies, is highlighted. Chapter 2 details work carried out on the CB[8]-mediated self-assembly of supramolecularblock copolymers from polymeric, and small molecule building blocks. Here, endgroup-functionalised polymer guests were shown to assemble with small molecule ditopicguests in the presence of CB[8] to form block copolymers. Copolymers of various molecularweights were assembled, and the supramolecular complexes were studied usingsolution viscometry and diffusion NMR. This study represented the first use of diffusionNMR for probing the assembly of polymeric guests with CB[8].Chapter 3 describes the self-assembly of CB[8] with complementary ditopic guests. Highmolecular weight supramolecular polymers are known to form through the step-growthassembly of complementary ditopic building blocks. Here we sought to probe CB[8]?sability to drive supramolecular polymerisation. Solution viscometry, ESI-MS, and diffusionNMR were used to investigate the self-assembly process, which indicated that cyclicoligomers had formed. The relatively low solubility of CB[8] in water was thought to bea major limitation to polymer formation in this instance. Important observations relating to the effect of salts on the solution viscosities and stabilitiesof the complexes, are also discussed. Chapter 4 places emphasis on the synthetic methods employed towards preparing multivalentguests for CB[8] binding studies. Our synthetic guests were based on watersolubleoligomers of ethylene glycol. A bidirectional elongation route is presented foraccessing higher molecular weight, and monodisperse ethylene glycol oligomers (n = 12)in suitable purity. Chapter 5 describes the assembly of protein-polymer conjugates, and the versatility ofdiffusion NMR as a means to probe the assembly process. Here, end group-functionalisedpoly(ethylene glycol) guests were appended to bovine serum albumin (BSA) through amixed chemical ligation-self assembly protocol. The NMR studies conducted are emphasisedhere, which served to complement other characterisation methods used thatare reported elsewhere. Chapter 6 discusses ongoing work on lipid-based guests, and the resulting liposome assembliesformed. Head group-functionalised phospholipid guests, and cholesterol-basedguests were synthesised. Phospholipid guests were obtained through an enzymatic route,a novelty in our group. Dye-encapsulated liposomes were then assembled, purified, andcharacterised by fluorescence microscopy. Finally, we sought to optimise lipid formulationsto enhance liposome stability, towards conducting molecular recognition studies inthe presence of CB[8].Chapter 7 then closes the thesis with concluding remarks that summarise the describedresearch, while highlighting points of note.

Polymer coatings are a versatile, efficient, and up-scalable platform for fabricating functionalised surfaces in many different applications. Functional surfaces, in particular, can be achieved by inducing a surface structure or a pattern within a polymer film, and in this Thesis, the focus has been on investigating functional structures that self-assemble spontaneously on a surface. Firstly, a polymer thin film coated on a non-wettable substrate is metastable and, if allowed to relax, may dewet into isolated droplets over the substrate. A novel phenomenon occurring in bilayers of spin-coated polymer films (of polar poly (4-vinylpyridine) (P4VP) on top of polystyrene (PS)) was investigated whereby dewetted P4VP droplets spontaneously align on the PS substrate, and the alignment extends over a large scale (millimetres). The aligned pattern results from a series of aligned defects on the P4VP film, which are formed during spin-coating. Secondly, a homogeneous ternary polymer mixture with a good solvent and a poor solvent is prone to undergoing phase separation (or phase inversion). As the good solvent evaporates, it triggers the mixture to separate into a polymer-rich phase and a polymer-lean phase mainly consisting of the solvent and non-solvent. When the latter evaporate, they leave a high density of air voids, and the final material is a highly porous polymer layer. Here, a structured porous polymer layer based on poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) was used as a platform for passive cooling and water collection. The phase inversion process was investigated as a function of a number of system parameters such as polymer grade, mixture composition, layer thickness, and humidity of the environment during phase inversion. The surfaces were then integrated within a prototype for passive atmospheric water harvesting, demonstrating promising avenues for future research.

The effects of counterion on the lyotropic liquid crystalline phase behaviour of some quaternary ammonium salts of perfluorodecanoic acid in water have been studied using a combination of optical polarising microscopy (OPM), deuterium nuclear magnetic resonance (211 NMR) and cryo-transmission electron microscopy (cryo-TEM). The results from the phase diagram studies flill into two groups. Firstly the ammonium (A) and tetramethylanmionium (TMA) counterions show a phase behaviour with nematic (N) and random mesh (MJi 1 (0)) phase which possess non-uniform interfacial curvature. The second group of surfactants with counterions, butyltrimethylammonium (BTMA), dibutyldimetylammonium (DBDMA), and tetrabutylammonium (TBA), form only a classical lamellar phase (La). For both DBDMA and TBA lower consolute behaviour has been observed. At fixed concentration in all five systems cryo-TEM visualises isotropic liquid phase structures that vary from sphere / rod micelles for A and TMA to vesicles / bilayer pieces for the other surfactants. These results are consistent with a reduction of the interfacial curvature of the aggregates, a phenomenon explained by a closer association of the counterion with the micellar surface. This is postulated to be driven by an increase in the size and hydrophobicity of the counter-ion from A to TBA. The correlated mesh phase (Mh i (R3 m)) is unique to the TMA surfactant of this series. It is extremely stable, both thermally and in surfactant concentration, when compared to such phases formed in other surfactant systems. To further elucidate the effect of countenon and investigate the mechanisms that stabilise mesh intermediate phases the effects of additives on the Mh 1 (R3 m) have been studied. The evolution of the phase behaviour and lyotropic phase structures formed in the TMA system have been studied upon the addition of salt (tetramethylammonium chloride, TMAC1), cosurfactant (111,1H-perfluoro-I-decanol, CiooI) and oil (perfluorooctane, C goil) using OPM, 211 NMR and small angle X-ray scattering (SAXS). Upon addition of a third component the Mh1(R3 m) is lost and a Mii j (0) stabilised. Further addition of the third component drives the formation of L. phase in the TMACI and C 10o1 addition systems. The structure of Mli 1 (R 3 m) phase is essentially unaltered over that of the binary phase irrespective of the amount or type of third component added. In the case of TMAC1 addition the formation of the Mh 1 (0) is driven by a reduction in the electrostatic interlayer interaction via a screening effect of the added counter-ions. In the C10o1 and C8oil addition systems the phase transition is driven by an alteration in the packing of the hydrophobic interior of the aggregates, which is termed a 'hydrophobic packing constraint'. SAXS experiments show that upon the transition from the Mh 1 (R3 m) to Mh1 (0) phase the surface area per molecule is conserved (within experimental error) and occurs more rapidly in the presence of C 10o1 and Cgoil indicating that the stability of the former over the latter requires a well defined intra-layer topology. The Mh 1(0) to L. transition is driven by a closure of defects as the additive concentration decreases the surface area per surfactant molecule via enhanced counter-ion binding in the TMACI experiments, or surface charge dilution in the C 10o1 addition systems.

Le travail décrit dans cette thèse couvre une étude fondamentale sur des canaux artificiels d'eau et sur des matériaux membranaires incorporant ces canaux. Structuré en quatre chapitres, la thèse commence par une présentation de l'état de l’art sur les systèmes biomimétiques de transport d'eau et des membranes biomimétiques. Au centre de tous ces travaux de recherche sont les protéines biologiques hautement efficaces et sélectives, les Aquaporines. Le deuxième chapitre présente les canaux artificiels d'eau à base d'imidazole-quartet. Les similitudes structurelles et fonctionnelles avec les Aquaporines sont discutées et caractérisées par plusieurs méthodes expérimentales. Les structures à l'état solide obtenues à partir de monocristaux présentent une organisation très similaire des I-quartets avec leurs homologues biologiques. Le biomimétisme fonctionnel du transport de l'eau a été démontré par des expériences cinétiques de transport à travers des systèmes vésiculaires. Le mécanisme de translocation de l'eau et l'organisation confinée dans des environnements lipidiques a été confirmé par des simulations dynamiques moléculaires, tandis que la preuve physique de l'eau orientée dipolaire dans les canaux intégrés aux lipides a été fournie par des expériences de spectroscopie IR polarisée. Le troisième chapitre présente de nouveaux canaux d'eau artificiels en utilisant une stratégie d'auto-assemblage. De nouveaux composés à base de diol, de tétrazacrown et de tryarilamine capables de transporter l'eau sont décrits. Le dernier chapitre décrits le passage du niveau moléculaire aux matériaux membranaires macroscopiques incorporant des canaux d'eau artificiels. Deux configuration membranaires différentes ont été décrites: des membranes en couche mince par l'incorporation de nanoparticules à base d'imidazole dans des polymères de polyamide et des membranes de la cellulose régénérée chimiquement greffée par des monomères de canaux d'eau artificiels. Les membranes ont été caractérisées par diverses méthodes d'imagerie et d'analyse et leurs performances ont été testées dans des expériences d'osmose inverse et de filtration d'osmose directe. La thèse est conclue avec une partie de conclusion générale, comprenant des perspectives pour les développements futurs
The work described in this thesis covers an in depth fundamental study of artificial water channels and of membrane materials incorporating these channels. Structured in four chapters, the thesis begins with a presentation of the state of the art in the field of biomimetic systems and membranes for water transport. The center of the described research work is the family of highly efficient and selective biological water transporter proteins, the Aquaporins. The second chapter presents the description of imidazole-quartet supramolecular artificial water channels. Structural and functional similarities with Aquaporins are discussed and based on several experimental methods. Single-solid state structures present very similar organization of confined water wires as found in their biological counterparts. Functional mimicry of water transport has been proved through stopped flow experiments in vesicular systems. Further characterization concerning water translocation mechanism and confined organization in lipid environments have been obtained through molecular dynamic simulations, while physical evidence of dipolar oriented water in lipid embedded channels has been provided by sum frequency generation experiments. The third chapter presents novel artificial water channels. New diol, tetrazacrown and tryarilamine based compounds have been described, with a main focus on design, synthesis, self-assembly and water transport properties. The last chapter makes the transition from the molecular systems to macroscopic membrane materials incorporating artificial water channels. Two different approaches have been described: thin film nanocomposite membranes based on the incorporation of imidazole-quartet nanoparticles in polyamide polymers and chemically grafted regenerated cellulose membrane through the use of custom monomers for the obtaining of artificial water channels. The membranes have been characterized through various imaging and analytical methods and their performances have been tested in reverse and forward osmosis experiments. The thesis is concluded with a general conclusion part, including perspectives for future developments

Thesis (Ph. D.)--Ohio State University, 2005.
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Mechanical assembly of systems and structures on the micro-scale can be inefficient as pthesiss of sub-millimeter dimensions are difficult to manipulate. Cutting edge manufacturing methods implement self-assembly as an approach to ordering micro and nano-sized parts into a desired arrangement. This thesis studies a technique utilizing surface tension as a method of actuating microparts on a liquid-liquid interface via lateral capillary interactions. Preliminary experimentation is conducted to investigate the feasibility of developing a new method for self-alignment of microparts by observing the influence of interfacial geometry on the movement of silicon tiles along a hexadecane-water interface. Different surface geometries are created by implementing vertical rods of different wetting properties that alter the curvature of the interface. Results demonstrate that the microparts attain an equilibrium separation distance from the vertical rods. It is indicated that this equilibrium distance is determined by the dimensions of the micropart and the curvature of the interface. With further investigation, these results may be used to cultivate a method for self-alignment of microparts into rings of a desired radius.

Pharmaceutical Sciences
Ph.D.
Today, drugs are an integral part of healthy human life, with new drug entities being introduced every year in clinic. The advancement of drug development brings complexity and variation, in terms of both physical and chemical properties. Some of these physicochemical characteristics are many times suboptimal, eventually requiring robust delivery systems that can precisely deliver the drugs to the desired tissues. Although many materials have been studied for the generation of drug delivery systems, there is always a need for biomaterials with better properties that can translate into superior delivery systems. In this context, new drug delivery systems that are interface-engineered at materials level for better stability and delivery efficiency in vitro and in vivo are introduced in this dissertation. In the first part of the dissertation, novel oil/water interface-engineered amphiphilic block copolymer micelles that were previously introduced by our lab were assessed for their stability in the presence of various esterase enzymes present in serum and on blood vessel walls, normally encountered by drug delivery systems on route to the targeted tissues. I also assessed the vulnerability of the polymeric micelles in presence of enzymes typically present either inside the tumor cells or secreted in the tumor microenvironment. I revealed the selective stability of empty- and docetaxel-loaded polymeric micelles to enzymatic degradation en route/in tumors and I have correlated this selective stability with polymer structure and interfacial engineering mentioned above. The unique delivery capabilities of interfacial-engineered polymeric micelles were tested in vivo using a mouse model of triple negative breast cancer. We proved that our novel engineered triblock copolymer-based drug delivery systems are superior to similar delivery systems made out of standard diblock copolymer micelles and also to the clinically used Taxotere® formulation towards cancer cell killing and tumor treatment, without displaying any significant toxicity in experimental animals. The second part of the dissertation focuses on the development and assessment of a pyridinium-based pseudo-gemini surfactant that combined the high nucleic acid packaging capacity of pyridinium lipids with the high transfection efficiency of gemini surfactants while displaying a reduced associated cytotoxic effect. I have analyzed the temperature treatment on compaction of nucleic acids into lipoplexes and I have established a high temperature annealing method for this purpose. This novel formulation technique allowed a substantial reduction of the amount of amphiphiles required to compact a specific amount of nucleic acids. This in turn also reduced the cytotoxic effect associated with the use of pyridinium amphiphiles. The effect of inclusion of colipids to lipoplex compaction, the robustness and the transfection efficiency of the lipid/nucleic acid lipoplex systems were assessed in detail, and correlations between formulation composition and biological activity were established. I was also able to show for the first time that pyridinium pseudo-gemini surfactants were able to compact different types of nucleic acids, including pDNA, mRNA and siRNA at lower charge ratios than standard, state-of-the art formulations used for this purposes. I also showed that irrespective to the nucleic acid compacted within the lipoplexes, the novel amphiphiles can efficiently deliver the cargo into the targeted cells even in the presence of very high concentration of serum, a premise for future use of these amphiphiles and formulations in vivo.
Temple University--Theses

Ce projet de thèse étudie la synthèse et les propriétés des triarylamines pour le transport d'électrons, d'ions ou de molécules d'eau, en se basant sur les propriétés d'auto-assemblage et de conductivité de certaines triarylamines, récemment découvertes par notre équipe. La thèse débute par une introduction sur la chimie supramoléculaire et les polymères supramoléculaires, et aborde ensuite dans son deuxième chapitre la synthèse et les propriétés d'analogues macrocycliques de triarylamine présentant des propriétés électromagnétiques intéressantes. Dans le chapitre suivant, ce travail de thèse explore l'applicabilité des triarylamines pour le transport biomimétique des ions métalliques et des molécules d'eau à travers des membranes de bicouches lipidiques. Le dernier chapitre de cette thèse s'intéresse ensuite à la fabrication de surfaces conductrices organiques / inorganiques hybrides par dopage de surfaces non conductrices avec des assemblages de triarylamines
Based on the navel and highly interesting self-assembly properties found for certain triarylamines, together with the resulting conducting properties, this PhD project investigates the synthesis and properties of triarylamines towards the transport of electrons, ions or water molecules. The thesis starts with an introduction on supramolecular chemistry and supramolecular polymers, and then discuss in its second chapter the synthesis and properties of macrocyclic triarylamine analogues with interesting electromagnetic properties. ln the following third chapter this thesis work explores the applicability of triarylamines towards the biomimetic transport of metal ions and water molecules through lipid bilayer membranes. The last chapter of this thesis then deals with the fabrication of hybrid organic/inorganic conducting surfaces through doping of non-conducting surfaces with triarylamine assemblies

There is a need for multifunctional polymer-particle complexes for use in biomedical applications such as for drug delivery or as MRI contrast agents where composition and stability are essential for the complexes to function. This work outlines a general methodology for rationally designing complexes stabilized with polymer brush layers using adapted star polymer models for brush extension and pair potential. Block copolymer micelles were first utilized for experimental validation by using the brush extension model to predict the size and the interaction model to predict the second virial coefficient, A2. Subsequently, the models were used to predict the size and colloidal stability of magnetite-polymer complexes using the modified Deryaguin-Verwey-Landau-Overbeek theory. Novel hydrophilic triblock copolymers comprised of poly(ethylene oxide) tailblocks and a carboxylic acid containing polyurethane center block were examined by static and dynamic light scattering (SLS and DLS), small angle neutron scattering (SANS), and densiometry. Under conditions when the charge is suppressed such as at low pH and/or high ionic strength, the polymer chains self-assemble into micelles, whereas unimers alone are present under conditions where charge effects are important, such as high pH and low ionic strength. A model for effective interaction between star polymers was used to obtain an expression for the second virial coefficient (A2) for micelles in solution. The values of A2 obtained using this method were compared with experimentally determined values for star polymers and micelles. In doing so, not only was a new means of calculating A2 a priori introduced, but the applicability of star polymer expressions to micellar systems was established. Through the analogy of micelles to sterically stabilized nanoparticles, this model was applied to water-soluble block copolymers adsorbed on magnetite nanoparticles for the purpose of tailoring a steric stabilizing brush layer. The sizes of the magnetite-polymer complexes were predicted using the star polymer model employed for the micelle study with an added layer to account for the anchor block. Colloidal stability was predicted from extended DLVO theory using the pair interaction. This work will lead to a better understanding of how to design ion-containing block copolymers for steric stabilization of metal oxide nanoparticles.
Ph. D.

Deposition of noble metal and semiconductor nanocrystalline thin films has received much attention. CdS and CdSe are important semiconductors used in optical devices. A wet chemical route which uses the interface of two immiscible liquids to control the growth and deposition of nanocrystalline thin films forms the basis of the current study. In this method, a metal precursor dissolved in toluene or decane is held in contact with a water layer containing a reducing or sulphiding agent. The reaction proceeds at the interface of the liquids and results in deposits adhering to the interfacial region. The products of such reactions typically consist of nanocrystals forming a thin film. Stable sols of Au, Ag were found to metathesize on contact with alkylamine in oil to form monolayer films that spread across large areas at the water/oil interface. The nature and properties of interfacial thin films depend on the alkylamine. Nanocrystalline thin films consisting of CdS adhering to the interface starting with a polydispersed aqueous sol of crystallites and alkylamine were obtained. The optical band gaps of the films formed are dependent on the alkylamine chain length, with the shortest chain yielding the largest gap. A systematic increase in particle diameters following adsorption is responsible for changes in the electronic structure of films. The formation of nanocrystalline films of CdS adhering at the interface using a toluene solution of cadmium diethyldithiocarbamate and aqueous Na2S solution, in the presence of tetraoctylammonium bromide (TOAB) in the aqueous phase, was investigated under various reaction parameters, while CdSe was obtained using Na2SeSO3 solution and the influences of deposition temperature and solution concentration were studied. A ternary water/decane/2-butoxyethanol /salt system was used to grow deposits of CdSe and CdS. Nanostructured thin films were obtained at the upper interface of the ternary system, between the emulsive middle layer and oil rich top phase. The influence of deposition conditions such as precursor concentrations and temperature, as well as the nature of the medium on the properties of the deposits was studied. Deposits grown using the ternary system were compared with those obtained using water/decane and water/toluene systems. Reaction parameters such as temperature, solution concentration and the size of CdS and CdSe were controlled. A thin film of CdS and CdSe nanocrystals was formed at the interface. The grain size was found to be dependent on reaction temperature and solution concentration, with higher temperatures and solution concentration resulting in larger grains. The nature of thin films obtained at the interface of two immiscible liquids and of a water/decane/2-butoxyethanol/salt ternary system were studied using Scanning and Transmission electron microscopy, X-ray diffraction and UV-visible spectroscopy.

This thesis mainly focuses on the rational design and preparation of bi-transition metal oxide materials for high-performance electrochemical catalysis, such as hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). To address the challenges of sluggish kinetics and large overpotentials in HER and OER, the effective strategy of morphology engineering, introducing a secondary metal element and supporting on carbon-based materials were carried out and discussed.

L’interface air-eau est un milieu où la tension de surface intervient en permanence pour minimiser l’énergie de la surface. Cette force est à l’origine des phénomènes capillaires que les organismes semi-aquatiques exploitent. L’objectif de cette thèse est d’étudier l’importance de ces phénomènes dans l’écologie des organismes semi-aquatiques en prenant les gyrins comme modèle. Les résultats montrent que le ménisque bipolaire produit par les gyrins est responsable d’auto-assemblables statiques entre individus immobiles. Les gyrins utilisent également différents types de nage pour minimiser les forces de résistance qu’ils rencontrent, notamment la force liée à la production d’onde. L’étude expérimentale de la perception d’objets immobiles suggère la perception des ménisques par les gyrins. L’écholocation grâce aux ondes de surface, supposée dans la littérature, ne peut cependant être exclue
The surface tension at the air-water interface is responsible for capillary phenomena minimizing surface energies. Semi-aquatic organisms have evolved to exploit this capillarity. The purpose of this thesis is to study the importance of capillary phenomena in the ecology of semi-aquatic organisms using whirligig beetles as a model. Results show that the bipolar meniscus produced around whirligig beetles is responsible for static self-assembly between individuals. These insects use different types of swimming to minimize resistance forces, especially the wave drag. The experimental study of the detection of immobile objects suggests that whirligig beetles perceive the menisci. Echolocation using surface waves, assumed in literature, cannot however be excluded

Depuis une dizaine d'années, les polymères ayant un comportement à UCST dans l'eau suscitent de plus en plus d’intérêt. Parmi eux, le poly(acrylamide-co-acrylonitrile) (P(Am- co-AN)) et le poly(N-acryloyl glucinamide) sont les plus populaires. Ils ont principalement été étudiés pour développer de nouveaux systèmes intélligents destinés à des applications biomédicales. Cependant, la reproductibilité de leur synthèse pour obtenir un polymère ayant une température de transition de phase (TCP) donnée n’est pas toujours aisée. Dans ce travail de thèse, nous avons dans un premier temps complété les études sur le P(Am-co-AN) décrites dans la littérature en réalisant sa synthèse dans l’eau par polymérisation radicalaire contrôlée par RAFT. Nous avons ensuite développé une nouvelle famille de (co)polymères à base d’acrylamide de N-cyanométhyle (CMAm) ou d’acrylamide de N-cyanoéthyle (CEAm) présentant un comportement de type UCST dans l’eau couvrant une très large gamme de TCP accessibles (~20-85 °C). De plus, nous avons synthétisé dans l’eau des copolymères à blocs à base des différents (co)polymères à UCST via le procédé PISA-RAFT en utilisant des macro-agents RAFT hydrophiles à base de poly(acrylamide de N,N-diméthyle) (PDMAc). Ce procédé nous a permis d’obtenir des nano-objets thermosensibles de différentes morphologies. Dans le cas des PDMAc-b-P(Am-co-AN), nous avons montré l’existence d’une transition morphologique fibres/sphères partiellement réversible, induite par le chauffage du milieu. Dans le cas des copolymères PDMAc-b-PCMAm, nous avons pu synthétiser -avec un bon contrôle- une large gamme de morphologies (sphères, fibres et vésicules)
Over the past decade, polymers exhibiting a UCST type behavior in water have gained more and more interest. Among them, poly(acrylamide-co-acrylonitrile) (P(Am-co-AN)) and poly(N- acryloyl glucinamide) are the most popular. They have been mainly studied for the develoment of new smart systems for biomedical applications. Yet, reproductibility of their synthesis to obtain polymers with the targeted phase transition temperature (TCP) is not always straightforward. In this thesis, we firstly completed previous studies available in the litterature on P(Am-co-AN) by synthesizing it in water using RAFT-controlled radical polymerization. We also developed a new familly of (co)polymers based on N-cyanomethylacrylamide (CMAm) and N-cyanoethylacrylamide (CEAm) exhibiting a UCST-type behavior in water covering a very large range of TCP (~20-85 °C). Moreover, we have shown that block copolymers composed of the former UCST type (co)polymers could be achieved with good polymerization control in water via the PISA-RAFT process using a poly(N,N- dimethylacrylamide) (PDMAc) macroRAFT agent. The process allowed us to obtain thermoresponsive nano-objects of different morpholgies. Remarkably, in the case of PDMAc-b-P(Am- co-AN), we have shown the existence of a partially reversible worms-to-spheres morphological transition induced by heating of the medium. In the case of PDMAc-b-PCMAm diblock copolymers, we have shown that a large range of morphologies, namely spheres, worms and vesicles, was accessible

Les polymères fluorés constituent une classe de polymères à part, aux propriétés remarquables (résistance chimique et thermique, ferroélectricité et piézoélectricité lorsqu‟ils sont semicristallins pour en citer quelques-unes). Les polymères fluorés ont trouvé de nombreuses applications industrielles. Toutefois, ils n‟ont pas encore attiré tout l‟intérêt qui leur est dû de la part de la communauté scientifique. Il reste en effet difficile de préparer des architectures polymères fluorées bien définies. Les techniques de synthèse développées et utilisées jusqu‟à présent permettent la synthèse d‟architectures polymères intéressantes, mais elles souffrent de deux inconvénients majeurs : 1) Elles ne permettent pas d‟accéder à de hautes masses molaires, et 2) les architectures obtenues ne sont pas bien définies. En conséquence, les études physiques de ségrégation de phases en films ou en masse, et ou bien celles qui portent sur la cristallisation des polymères fluorés ont été limitées aux homopolymères et aux mélanges. De même, il existe très peu de travaux sur l‟auto-assemblage d‟architectures polymères fluorées en solution. A travers une étude cinétique approfondie, des caractérisations détaillées en spectroscopie (NMR) ainsi que des calculs DFT, cette étude a révélé la remarquable éfficacité de la RAFT pour synthétiser des architectures de PVDF bien définies. L‟auto-assemblage de blocs PVDF-b-PVA ainsi que l‟autoassemblage induit par la polymérisation de copolymères PVAc-b-PVDF ont dévoilé les premières nanostructures de type coeur/coquille et rose des sables à base de PVDF
Fluoropolymers constitute a specific class of polymers, with remarkable properties (high resistance to chemicals and heat, ferroelectricity and piezoelectricity for semi-crystalline polymers, to name a few). Fluoropolymers have found many industrial applications. However, fluoropolymers have not yet attracted all the interest they deserve from the scientific community. It is indeed difficult to prepare well-defined fluorinated polymeric architectures. The synthesis techniques developed and used so far allow the preparation of interesting architectures, but they suffer from two major drawbacks: 1) They do not allow access to high molar mass, and 2) The resulting architectures are ill-defined. As a result, physical chemistry studies of the phase segregation phenomena in films or in the bulk, or of the crystallization of fluorinated polymers were for the most part limited to homopolymers and blends. Similarly, very few studies of the self-assembly in solution of fluorinated polymeric architectures have been reported. Throughout deeper kinetic study, NMR characterizations and DFT calculation, this study reveals the remarkable efficiency of the RAFT polymerization to synthesize well-defined PVDF–based architectures. Self-assembly of PVDF-b-PVA block copolymers as well as polymerization-induced self-assembly of PVAc-b-PVDF block copolymers led to the first crystalline core/shell and desert-rose PVDF-based nanostructures

La chimie des foldamères est un domaine de recherche en pleine expansion où les chimistes explorent la construction d’architectures artificielles variées mimant les structures repliées des biopolymères naturels. Les foldamères d’oligoamides quinoline, constituent une branche importante des foldamères montrant de nombreuses caractéristiques attractives, incluant la stabilité et la prédictibilité de leurs conformations repliées, qui en font de bons candidats pour des applications biologiques. Jusqu’à présent, la plupart des études sur les foldamères d’oligoamides quinolines ont été menées dans des solvants organiques. Cette thèse a pour objectif d’étendre leur portée au milieu aqueux et présente plusieurs méthodologies pour parvenir à leur solubilité, leur repliement, la variation de leurs chaines latérales, leur agrégation et leur capacité à former des cristaux dans l’eau.Tout d’abord, une méthode de synthèse en phase solide a été développée permettant l’accès rapide aux foldamères hybrides α-amino acide/quinoline (X/Q). Leur étude dans l’eau montre que contrairement aux foldamères hybrides de type (XQ)n, ceux de type (XQ2)n sont capables d’adopter une conformation hélicoïdale présentant un alignement des chaines α-amino acides dans l’espace. Ensuite, plusieurs chaines latérales courtes ont été identifiées pour doter les foldamères aromatiques d’une solubilité et d’une capacité à cristalliser dans l’eau. Six oligoamides quinoline ont ainsi été synthétisés pour une étude modèle. Des cristaux ont été obtenus pour toutes les séquences sauf une, présentant une excessive solubilité dans l’eau. Enfin, des efforts ont été faits pour construire des faisceaux d’hélices auto-assemblés dans l’eau à base d’effets hydrophobes et d’interactions électrostatiques. Les études RMN et cristallographiques ont indiqué que les effets hydrophobes étaient plus faibles qu’attendu et ne provoquaient pas d’agrégation forte
Foldamer chemistry is a rapidly expanding research field where chemists explore the construction of various artificial architectures that mimic the folded structures of biopolymers found in nature. Quinoline oligoamide foldamers, as an important branch of foldamers, have been shown to possess many desirable features, including stability and predictability of their folded conformations, and are promising candidates to achieve biological applications. Up to now, most investigations of quinoline oligoamide foldamers have been carried out in organic solvents. This thesis is aimed to expand their scope in aqueous medium and presents several methodologies to achieve solubility, folding, side-chain variation, aggregation and crystal growth ability in water.First, a solid phase synthesis method was developed to enable the fast access to α-amino acid/quinoline (X/Q) hybrid oligoamide foldamers. The study of these hybrid foldamers in water showed that contrary to (XQ)n-type foldamers the (XQ2)n-type foldamers could adopt aromatic helical conformations with α-amino acid side chains aligned in space. Then, several short side chains were identified to endow aromatic foldamers with both solubility in, and crystal growth ability from water. Six quinoline oligoamides displaying these side chains were synthesized as a case study. Crystals were obtained from aqueous medium in all cases but one, exceedingly soluble in water. At last, efforts were made to construct self-assembled aromatic helix bundles in water based on hydrophobic effects and electrostatic interactions. NMR and crystallographic studies indicated that hydrophobic effects are weaker than expected and not strongly conducive of aggregation

Parmi les différentes techniques permettant d'assembler à la fois mécaniquement et électriquement les puces empilées, le collage direct de surfaces mixtes Cu-SiO2 représente l'option la plus prometteuse à ce jour. En effet, cette méthode permet d'atteindre la densité d'interconnexions de 10^6/cm² visée par l'industrie, tout en offrant une faible résistivité de contact et une excellente fiabilité. Les méthodes d’assemblages actuelles reposent sur l’utilisation d’outils de Pick&place par l’intermédiaire desquels les puces sont positionnées mécaniquement. Cette technique rencontre néanmoins de plus en plus de difficultés à concilier précision d’alignement et cadence d’assemblage. Cette thèse propose d’adresser cette problématique au travers de la mise au point d’un procédé d’auto-assemblage assisté par capillarité et collage direct. Grâce à l’utilisation des forces de capillarités, il est possible de réaliser l’alignement des puces de façon spontanée : on parle alors d’auto-assemblage. La première partie de ce manuscrit présente une analyse synthétique des méthodes d’assemblages et d’interconnexions existantes et statue sur l’état de maturité de chaque procédé. Cette partie permet par la même occasion d’introduire les mécanismes de collages SiO2-SiO2 sur lesquels repose la méthode d’assemblage développée dans ce manuscrit. Un design de puce permettant la mise en œuvre du procédé d’auto-assemblage est ensuite établit dans la seconde partie. La capacité de la puce à confiner le film de liquide apparait comme l’élément moteur du processus d’auto-alignement. Des auto-assemblages présentant des valeurs d’alignement inférieur au micromètre sont ainsi obtenus, tout en conservant un procédé répétable. La mise en place de simulations numériques permettant de modéliser l’effet d’auto-alignement est présenté dans la troisième partie. Ce modèle a ensuite été généralisé a des puces de formes polygonales. Enfin la dernière partie présente le transfert du procédé d’auto-assemblage a des puces présentant des surfaces de cuivre et d’oxyde de silicium. L’utilisation de ce type de puce a notamment permis de valider la viabilité électrique du processus d’auto-assemblage
Among the various techniques allowing to assemble both mechanically and electrically stacked chips, the direct bonding of Cu-SiO2 mixed surfaces is the most promising option to date. Thanks to this method, the interconnection density of 106/cm² aimed by the industry is achievable, while providing a low contact resistivity and excellent reliability.Current assemblies’ processes are based on Pick&place tools thanks to which the dies are mechanically placed.Nevertheless, these tools have difficulties to council high throughput and high alignment accuracy. This thesis proposes to address this issue through the development of a process of self-assembly assisted by capillary forces and direct bonding.Through the use of capillaries forces, it is possible to achieve spontaneously chips alignment: it is called self-assembly. The first part of this manuscript presents a synthetic analysis of the different assemblies and interconnections technics and decides on the maturity of each process.As the same time, this section allows to introduce the SiO2 -SiO2 bonding mechanisms underlying the assembly method developed in this manuscript.A specific chip design is then established in a second part allowing deploying self-assemblies with SiO2 full sheet chips.The ability of the chip to confine the liquid film appears as the driving element of the self- alignment process. Self- assemblies with alignment values lower than one micrometer are obtained while maintaining a repeatable process. The introduction of numerical simulations to model the self-alignment effect is presented in the third part. This model was then generalized has polygonal shaped chips. Finally the last part presents the transfer of the self- assembly process on SiO2-Cu patterned chips.The use of this kind of chip has enabled to validate the electrical viability of the self-assembly process

Chimie dynamique: reconnaissance de nucléobases par des récepteurs synthétiques et isomérie cis-trans d'hydrazones acylées.Ce travail traite du développement des systèmes moléculaires qui peuvent s'adapter à l'addition de substances qui agissent comme un gabarit. Cette approche permet d'isoler une espèce majeure à partir d'un mélange de composés par le biais de la chimie combinatoire dynamique (CCD). La première partie de ma thèse de doctorat inclus l'utilisation d'un ADN simple brin (ADNsb) comme un gabarit pour le transfert d'information par auto-assemblage de récepteurs sans avoir besoin d'enzyme. De nouveaux récepteurs de l'adénine et de la guanine (pinces A et G) solubles dans l'eau ont été conçues dans ce but. Une approche utilisant la résonance magnétique nucléaire (RMN) a été utilisée pour déterminer l'affinité de liaison comme preuve d'une reconnaissance spécifique et efficace. Une évaluation dans l'eau par dichroïsme circulaire (CD) et mesure de la température de fusion par UV (Tm) a été réalisée. Cela a permis de tester respectivement la capacité d'auto-assemblage entre les pinces et un modèle ADNsb, et la force du processus de coopérativité. La deuxième partie de ce travail est axée sur le tri spontanné de motifs pyridine acylhydrazone et sur les configurations intéressantes qu'ils adoptent. Nous avons étudié la synthèse d'une série de motifs pyridine acylhydrazone: dimère, trimères et pentamères. Des études RMN ont permis d'évaluer les changements dans l'équilibre configurationnel cis / trans de ces systèmes dynamiques. Les études ont montré que l'équilibre attendu est biaise la cis acylhydrazone pyridine isomère a été observée par diffraction des rayons X
Dynamic chemistry: nucleobase recognition by synthetic receptors and cis-trans acylhydrazone isomerism. This work deals with the development of molecular systems which can adapt upon the addition of substances that act as templates. This approach enables one major species to be identified from a mixture of compounds through the use of dynamic combinatorial chemistry (DCC). The first part of my PhD included the use of a single stranded DNA (ssDNA) as a template for information transfer via the self-assembly of receptors without the need for enzymes. New water soluble adenine and guanine receptors (A and G clamps) were designed and synthesised for this purpose. Nuclear magnetic resonance (NMR) titration studies were carried out to calculate the binding affinity and as a proof of specific and efficient recognition. An assessment in water via circular dichroism (CD) and UV temperature melting (Tm) studies was carried out. This tested the ability for self-assembly between the clamps and a ssDNA template and the strength of the cooperative process respectively. The second part of my PhD focused on the self-sorting of acylhydrazone pyridine motifs and the interesting configurations they adopt. The feasibility to synthesise these acylhydrazone pyridine motifs (dimer, trimers and pentamers) was investigated. X-ray and NMR studies showed that the equilibrium was found to be biased in an unusual way, and the cis acylhydrazone pyridine isomer was observed

The development of micro and nano-electromechanical systems (MEMS and NEMS) with entirely new or improved functionalities is typically based on novel or improved designs, materials and fabrication methods. However, today’s micro- and nano-fabrication is restrained by manufacturing paradigms that have been established by the integrated circuit (IC) industry over the past few decades. The exclusive use of IC manufacturing technologies leads to limited material choices, limited design flexibility and consequently to sub-optimal MEMS and NEMS devices. The work presented in this thesis breaks new ground with a multitude of novel approaches for the integration of non-standard materials that enable the fabrication of 3D micro and nanoelectromechanical systems. The objective of this thesis is to highlight methods that make use of non-standard materials with superior characteristics or methods that use standard materials and fabrication techniques in a novel context. The overall goal is to propose suitable and cost-efficient fabrication and integration methods, which can easily be made available to the industry. The first part of the thesis deals with the integration of bulk wire materials. A novel approach for the integration of at least partly ferromagnetic bulk wire materials has been implemented for the fabrication of high aspect ratio through silicon vias. Standard wire bonding technology, a very mature back-end technology, has been adapted for yet another through silicon via fabrication method and applications including liquid and vacuum packaging as well as microactuators based on shape memory alloy wires. As this thesis reveals, wire bonding, as a versatile and highly efficient technology, can be utilized for applications far beyond traditional interconnections in electronics packaging. The second part presents two approaches for the 3D heterogeneous integration based on layer transfer. Highly efficient monocrystalline silicon/ germanium is integrated on wafer-level for the fabrication of uncooled thermal image sensors and monolayer-graphene is integrated on chip-level for the use in diaphragm-based pressure sensors. The last part introduces a novel additive fabrication method for layer-bylayer printing of 3D silicon micro- and nano-structures. This method combines existing technologies, including focused ion beam implantation and chemical vapor deposition of silicon, in order to establish a high-resolution fabrication process that is related to popular 3D printing techniques.

QC 20121207

Three-dimensional (3D) integration of micro- and nano-electromechanical systems (MEMS/NEMS) with integrated circuits (ICs) is an emerging technology that offers great advantages over conventional state-of-the-art microelectronics. MEMS and NEMS are most commonly employed as sensor and actuator components that enable a vast array of functionalities typically not attainable by conventional ICs. 3D integration of NEMS and ICs also contributes to more compact device footprints, improves device performance, and lowers the power consumption. Therefore, 3D integration of NEMS and ICs has been proposed as a promising solution to the end of Moore’s law, i.e. the slowing advancement of complementary metal-oxide-semiconductor (CMOS) technology.In this Ph.D. thesis, I propose a comprehensive fabrication methodology for heterogeneous 3D integration of NEM devices directly on top of CMOS circuits. In heterogeneous integration, the NEMS and CMOS components are fully or partially fabricated on separate substrates and subsequently merged into one. This enables process flexibility for the NEMS components while maintaining full compatibility with standard CMOS fabrication. The first part of this thesis presents an adhesive wafer bonding method using ultra-thin intermediate bonding layers which is utilized for merging the NEMS components with the CMOS substrate. In the second part, a novel NEM switch concept is introduced and the performance of CMOS-integrated NEM switch circuits for logic and computation applications is discussed. The third part examines two different packaging approaches for integrated MEMS and NEMS devices with either hermetic vacuum cavities or low-cost glass lids for optical applications. Finally, a novel fabrication approach for through silicon vias (TSVs) by magnetic assembly is presented, which is used to establish an electrical connection from the packaged devices to the outside world.
Tredimensionell (3D) integration av mikro- och nano-elektromekaniska system (MEMS/NEMS) med integrerade kretsar (ICs) är en ny teknik som erbjuder stora fördelar jämfört med konventionell mikroelektronik. MEMS och NEMS används oftast som sensorer och aktuatorer då de möjliggör många funktioner som inte kan uppnås med vanliga ICs.3D-integration av NEMS och ICs bidrar även till mindre dimensioner, ökade prestanda och mindre energiförbrukning av elektriska komponenter. Den nuvarande tekniken för complementary metal-oxide-semicondictor (CMOS) närmar sig de fundamentala gränserna vilket drastiskt begränsar utvecklingsmöjligheten för mikroelektronik och medför slutet på Moores lag. Därför har 3D-integration identifierats som en lovande teknik för att kunna driva vidare utvecklingen för framtidens elektriska komponenter.I denna avhandling framläggs en omfattande fabrikationsmetodik för heterogen 3D-integration av NEMS ovanpå CMOS-kretsar. Heterogen integration betyder att både NEMS- och CMOS-komponenter byggs på separata substrat för att sedan förenas på ett enda substrat. Denna teknik tillåter full processfrihet för tillverkning av NEMS-komponenter och garanterar kompatibilitet med standardiserade CMOS-fabrikationsprocesser.I den första delen av avhandlingen beskrivs en metod för att sammanfoga två halvledarskivor med en extremt tunn adhesiv polymer. Denna metod demonstreras för 3D-integration av NEMS- och CMOS-komponenter. Den andra delen introducerar ett nytt koncept för NEM-switchar och dess användning i NEM-switch-baserade mikrodatorchip. Den tredje delen presenterar två olika inkapslingsmetoder för MEMS och NEMS. Den ena metoden fokuserar på hermetisk vakuuminkapsling medan den andra metoden beskriver en lågkostnadsstrategi för inkapsling av optiska komponenter. Slutligen i den fjärde delen presenteras en ny fabrikationsteknik för så kallade ”through silicon vias” (TSVs) baserad på magnetisk självmontering av nickeltråd på mikrometerskala.

20170519

This thesis draws on David Harvey’s concept of “accumulation by dispossession” and an international political economy (IPE) approach centred on the institutional arrangements and power structures that privilege certain actors and values, in order to critique current capitalist practices of primitive accumulation by the global corporate extractive industry. The thesis examines how accumulation by dispossession by the global extractive industry is facilitated by the “free entry” or “free mining” principle. It does so by focusing on Canada as a leader in the global extractive industry and the spread of this country’s mining laws to other countries – in other words, the transnationalisation of norms in the global extractive industry – so as to maintain a consistent and familiar operating environment for Canadian extractive companies. The transnationalisation of norms is further promoted by key international institutions such as the World Bank, which is also the world’s largest development lender and also plays a key role in shaping the regulations that govern natural resource extraction. The thesis briefly investigates some Canadian examples of resource extraction projects, in order to demonstrate the weaknesses of Canadian mining laws, particularly the lack of protection of landowners’ rights under the free entry system and the subsequent need for “free, prior and informed consent” (FPIC). The thesis also considers some of the challenges to the adoption and implementation of the right to FPIC. These challenges include embedded institutional structures like the free entry mining system, international political economy (IPE) as shaped by international institutions and powerful corporations, as well as concerns regarding ‘local’ power structures or the legitimacy of representatives of communities affected by extractive projects. The thesis concludes that in order for Canada to be truly recognized as a leader in the global extractive industry, it must establish legal norms domestically to ensure that Canadian mining companies and residents can be held accountable when there is evidence of environmental and/or human rights violations associated with the activities of Canadian mining companies abroad. The thesis also concludes that Canada needs to address underlying structural issues such as the free entry mining system and implement FPIC, in order to curb “accumulation by dispossession” by the extractive industry, both domestically and abroad.

碩士
中原大學
物理研究所
98
Self-assembly of Au nanoparticles from water phase to oil/water interface is caused by adding ethanol into oil/water system, which reduce not only the surface tension of oil/water interface but the surface charge of Au nanoparticles. In our assumption, some parts of radicals of citrate acid around Au nanoparticles would replaced by ethanol, so that the Au nanoparticles could emerge to oil/water interface with ethanol, which tend to keep higher concentration at interface of colloid Au solution. This phenomenon was discussed by measuring the change of transmission intensity before and after the addition of ethanol by UV-Vis spectroscopy, and we found that the transmission intensity enhanced with increasing the volume percentage of ethanol in colloid Au solution. Besides, we also examined the particle size of original colloid Au solution by Dynamic Light Scattering(DLS), and analyzed the structures of Au nanoparticle film by Atomic Force Microscopy(AFM)and Scanning Electron Microscopy(SEM). We found that the particle size would not change after react, and the self-assembly of Au nanoparticles seems likely linear aggregation. On the other hand, we know that the Au nanoparticle films were covered with some oil phase solution because the contact angle of films were so large.

L’obbiettivo di questo lavoro di tesi è stato quello di ricercare i criteri chimico-fisici necessari per definire una formulazione “ottimale” di detergenza e predire la sua efficienza nella rimozione dello sporco da superfici dure.

The self-assembly of several pyrene-labelled amphiphilic macromolecules in water was characterized by fluorescence. Information on their self-assembly was obtained by monitoring the level of pyrene aggregation in solution. A measure of the level of association was obtained by determining the fraction of aggregated pyrene of the labelled macromolecules from the global analysis of their monomer and excimer fluorescence decays. Global analysis limits the degrees of freedom of the analysis thus reducing the error on the parameters retrieved from the analysis. Extensive developments in the global analysis of the pyrene monomer and excimer decays enabled the first characterization of the molar absorbance coefficient of the pyrene aggregates formed by aqueous solutions of pyrene-labelled poly(N,N-dimethylacrylamide) (PyPDMA) and poly(ethylene oxide) (PyPEO). The molar absorbance coefficients of the pyrene aggregates determined for PyPDMA and PyPEO were both found to be broader and red-shifted compared to that of unaggregated pyrene. These results agree with observations found in the scientific literature made by using absorption and excitation fluorescence measurements. Attempts to determine the molar absorbance coefficient of pyrene-labelled hydrophobically-modified alkali-swellable emulsion (PyHASE) polymers were unsuccessful. The inability to characterize the pyrene aggregates of PyHASE was attributed to the greater complexity of the PyHASE polymer compared to PyPDMA and PyPEO. For these simpler pyrene-labelled polymers, a protocol has been established which uses the global analysis of the pyrene monomer and excimer decays to determine quantitatively the level of association of pyrene-labelled polymers as well as the molar absorbance coefficient of their aggregates. Changes in the level of aggregation of pyrene-labelled lipids (PLLs) having head groups bearing an alcohol (PSOH) or imido diacetic acid (PSIDA) embedded in 1-palmitoyl-2-oleyl-3-sn-phosphatidylcholines (POPC) or distearylphosphatidylcholine (DSPC) liposomes were probed by fluorescence. Distribution of the PLLs in the fluid POPC membrane was found to be homogeneous while the PLLs phase-separated into amorphous channels created in the DSPC membranes. Multivalent cations Cu2+ and La3+ were found to bind to PSIDA, hindering diffusional encounters between unaggregated PSIDA but leaving the PLL aggregates intact. Using the fluorescence quenching ability of Cu2+, the viscosity of the amorphous channels of the DSPC membrane was determined to be about six times greater than that of the more fluid POPC membrane. Simultaneous rheological and fluorescence measurements were achieved by interfacing a rheometer with time-resolved and steady-state fluorometers using fiber-optic cables. This joint set up enabled the simultaneous rheological and fluorescence measurements of PyHASE solutions having concentrations ranging from 0.5 w/w% to 5 w/w%. The level of association of the PyHASE solutions was tracked using fluorescence at shear rates of 0, 0.1 and 100 s–1. Despite the presence of shear thinning leading to viscosity drops of up to four orders of magnitude, no change in the fluorescence and hence the level of association was observed. The lack of change in level of association implied that the mechanism of shear thinning is due to a switching from inter- to intramolecular association rather than a drop in the level of association. This information will prove useful for future models attempting to predict the rheological behaviour of sheared associative polymers.

The main objective of this thesis was the design and synthesis of perylene bisimide dyes with sufficient water-solubility for the construction of self-assembled architectures in aqueous solutions. Beside these tasks another goal of this project was the control over the self-assembly process in terms of aggregate size and helicity, respectively. Within this thesis an appropriate synthesis for spermine-functionalized perylene bisimide dyes was developed and conducted successfully. The characterization of these building blocks and their course of self-assembly were investigated by NMR, UV/Vis and fluorescence spectroscopy as well as by atomic force and transmission electron microscopy. For the better understanding of the experimental results theoretical calculations were performed
Ziel dieser Dissertation war das Design und die Synthese von Perylenbisimiden mit hinreichender Wasserlöslichkeit, die für den Aufbau von selbständig assemblierten Strukturen in wässrigen Lösungen verwendet werden sollen. Ein weiteres Ziel dieses Projektes war die Kontrolle über den Prozess der Selbstanordnung hinsichtlich der Aggregatgröße beziehungsweise deren Helizität. Im Rahmen dieser Doktorarbeit wurde eine entsprechende Synthese für Spermin-funktionalisierte Perylenbisimide entworfen und erfolgreich durchgeführt. Die Charakterisierung dieser Bausteine und der Prozess deren Selbstanordnung wurde mit Hilfe von NMR-, UV/Vis- und Fluoreszenz-Spektroskopie aber auch mit Rasterkraft- und Elektronentransmissionsmikroskopie durchgeführt. Für das bessere Verständnis der experimentellen Ergebnisse wurden theoretische Berechnungen durchgeführt

No
We demonstrate the self-assembly of bola-amphiphile-type conjugates of dipeptides and perylene bisimide (PBI) in water and other polar solvents. Depending on the nature of the peptide used (glycine-tyrosine, GY, or glycine-aspartic acid, GD), the balance between H-bonding and aromatic stacking can be tailored. In aqueous buffer, PBI-[GY]2 forms chiral nanofibers, resulting in the formation of a hydrogel, while for PBI-[GD]2 achiral spherical aggregates are formed, demonstrating that the peptide sequence has a profound effect on the structure formed. In water and a range of other polar solvents, self-assembly of these two PBI-peptides conjugates results in different nanostructures with highly tunable fluorescence performance depending on the peptide sequence employed, e.g., fluorescent emission and quantum yield. Organogels are formed for the PBI-[GD]2 derivative in DMF and DMSO while PBI-[GY]2 gels in DMF. To the best of our knowledge, this is the first successful strategy for using short peptides, specifically, their sequence/structure relationships, to manipulate the PBI nanostructure and consequent optical properties. The combination of controlled self-assembly, varied optical properties, and formation of aqueous and organic gel-phase materials may facilitate the design of devices for various applications related to light harvesting and sensing.

“Solvation water role in driving structural conformation and self-assembly of peptides and proteins”, the title of the present thesis, summarizes the objective of my three years PhD course aimed to investigate the relationship existing between the structure of biomolecules in solution and their mutual influence with surrounding water molecules. The three year work has been mainly experimental and principally focused in analyzing the capability of vibrational spectroscopies and some non-linear spectroscopic techniques to disentangle various contributions to solvent-molecule interactions. However to gain a deeper insight in the comprehension of such a complex problem, different types of experimental methods and theoretical modeling have supplemented spectroscopic techniques. A general survey of UV Resonant Raman (UVRR) spectroscopy and picosecond transient grating (TG) technique is reported in Chapter 2. The specific interactions of water molecules with glutathione tripeptide dissolved in pure water and water/salts mixtures are investigated experimentally by UVRR spectroscopy and modeled by molecular dynamics simulations. The results are presented in Chapter 3 and focus on the peptide-solvent interactions at the peptide site of glutathione thanks to the high selectivity of UVRR spectroscopy. Spectra are collected and analyzed as a function of concentration, pH, temperature and ion nature. OH stretching and amide modes spectral regions result very sensitive to the variations of the experimental conditions. The output provides a picture of the hydrogen-bonding network around glutathione. The number and the strength of hydrogen bonds increase in the deprotonated form of the tripeptide that exhibits a more marked capacity in decreasing the intermolecular order of water in its hydration shell. Potassium salts and imidazolium based ionic liquids of the halogen series are used to investigate the ions effect on glutathione structure and hydration shell. UVRR spectra present specific features possessing a great dependence on the nature of the anion present in solution rather than that of the cation, suggesting a strong capacity of anions to modify the glutathione structure and its hydration shell. There is a strong evidence that chloride and bromide anions interact at the NH site of glutathione reducing the possibility to form hydrogen bonds with water molecules and making the environment more hydrophobic than in pure water. Instead, iodide anion increases the number of water molecules at the peptide site, creating a strong polar environment. The spectroscopic and computational data are in perfect agreement and their interpretation can be based on the peptide link resonance model. In all the studied solvation environments, a progressive reduction in the strength of hydrogen bond interactions on amide sites is probed upon the increment of temperature, accompanied by conformational changes involving also the trans-cis isomerization of glutathione. Chapter 4 deals with the results of the study on self-crowded lysozyme solutions characterized by different degrees of aggregation and networking. Lysozyme has been widely investigated, as a convenient model protein, due to its ability to form amyloid fibrils in acidic conditions at high temperatures. Most of these past studies involved rather diluted samples in which fibril assembly is relatively slow. More rarely the formation of amyloid aggregates was examined in concentrated conditions, despite their relevance in different fields, from cellular biology and medicine to biomaterial and food technologies. In the present study, thermal unfolding and aggregation of highly concentrated (>100 mg/ml) lysozyme solutions at pH=1.8 are investigated. A method is designed to form protein hydrogels in a few hours. Their properties can be easily modulated selecting the curing temperature. The whole gelation process was monitored in situ by Fourier transform infrared (FTIR) spectroscopy assisted by hydrogen/deuterium isotopic exchange, to probe conformational changes and amyloid structuring. Specific molecular conformations are put in relation to thermodynamic properties by calorimetric measurements, to structural information by small angle x-ray and neutron scattering and to viscoelastic properties by means of rheology and TG experiments. This multi-technique approach is necessary in order to obtain a consistent picture on structure-property correlation in self-crowded protein samples. Aggregates constituted by antiparallel cross β-sheet links grow up quickly (less than two hours) within the 45-60 °C temperature range, leading to temperature-dependent quasi-stationary level of amyloid structures, attributed to kinetically trapped oligomers. Upon subsequent cooling, hydrogels develop quickly through the formation of non-specific inter-oligomer contacts. Due to this supramolecular assembly, the hydrogel is transparent, thermo-reversible and rather weak from a mechanical point of view. Lysozyme solutions can be recovered back to a large extent, following a process of oligomer-to-monomer dissociation and refolding. Overall, evidence is given of the possibility of easily forming protein hydrogels in self-crowding conditions constituted by kinetically trapped amyloid oligomers, interconnected by weak interactions. This type of gels might be relevant in different fields, when concentrated protein systems experience denaturing conditions.

Yes
Amphiphilic nucleobase-containing block copolymers with poly(oligo(ethylene glycol) methyl ether methacrylate) as the hydrophilic block and nucleobase-containing blocks as the hydrophobic segments were successfully synthesized using RAFT polymerization and then self-assembled via solvent switch in aqueous solutions. Effects of the common solvent on the resultant morphologies of the adenine (A) and thymine (T) homopolymers, and A/T copolymer blocks and blends were investigated. These studies highlighted that depending on the identity of the common solvent, DMF or DMSO, spherical micelles or bicontinuous micelles were obtained. We propose that this is due to the presence of A–T interactions playing a key role in the morphology and stability of the resultant nanoparticles, which resulted in a distinct system compared to individual adenine or thymine polymers. Finally, the effects of annealing on the self-assemblies were explored. It was found that annealing could lead to better-defined spherical micelles and induce a morphology transition from bicontinuous micelles to onion-like vesicles, which was considered to occur due to a structural rearrangement of complementary nucleobase interactions resulting from the annealing process.
European Research Council (ERC), University of Warwick, Engineering and Physical Sciences Research Council (EPSRC), National Science Foundation (U.S.) (NSF)

Une compréhension approfondie et un meilleur contrôle de l'auto-assemblage des copolymères diblocs (séquencés) et de leurs complexes à l'interface air/eau permettent la formation contrôlée de nanostructures dont les propriétés sont connues comme alternative à la nanolithographie. Dans cette thèse, des monocouches obtenues par les techniques de Langmuir et de Langmuir-Blodgett (LB) avec le copolymère dibloc polystyrène-poly(4-vinyl pyridine) (PS-PVP), seul ou complexé avec de petites molécules par liaison hydrogène [en particulier, le 3-n-pentadécylphénol (PDP)], ont été étudiées. Une partie importante de notre recherche a été consacrée à l'étude d'une monocouche assemblée atypique baptisée réseau de nanostries. Des monocouches LB composées de nanostries ont déjà été rapportées dans la littérature mais elles coexistent souvent avec d'autres morphologies, ce qui les rend inutilisables pour des applications potentielles. Nous avons déterminé les paramètres moléculaires et les conditions expérimentales qui contrôlent cette morphologie, la rendant très reproductible. Nous avons aussi proposé un mécanisme original pour la formation de cette morphologie. De plus, nous avons montré que l'utilisation de solvants à haut point d’ébullition, non couramment utilisés pour la préparation des films Langmuir, peut améliorer l'ordre des nanostries. En étudiant une large gamme de PS-PVP avec des rapports PS/PVP et des masses molaires différents, avec ou sans la présence de PDP, nous avons établi la dépendance des types principaux de morphologie (planaire, stries, nodules) en fonction de la composition et de la concentration des solutions. Ces observations ont mené à une discussion sur les mécanismes de formation des morphologies, incluant la cinétique, l’assemblage moléculaire et l’effet du démouillage. Nous avons aussi démontré pour la première fois que le plateau dans l'isotherme des PS-PVP/PDP avec morphologie de type nodules est relié à une transition ordre-ordre des nodules (héxagonal-tétragonal) qui se produit simultanément avec la réorientation du PDP, les deux aspects étant clairement observés par AFM. Ces études ouvrent aussi la voie à l'utilisation de films PS-PVP/PDP ultraminces comme masque. La capacité de produire des films nanostructurés bien contrôlés sur différents substrats a été démontrée et la stabilité des films a été vérifiée. Le retrait de la petite molécule des nanostructures a fait apparaître une structure interne à explorer lors d’études futures.
Deeper understanding and control of the self-assembly of diblock copolymers and their complexes at the air/water interface allow the formation of nanopatterns with known properties to provide a competitive substitute to nanolithography. In this dissertation, Langmuir and Langmuir-Blodgett (LB) monolayers obtained from polystyrene-poly(4-vinyl pyridine) diblock copolymers (PS-PVP), alone and hydrogen-bonded by various small molecules [particularly, 3-n-pentadecylphenol (PDP)], have been extensively investigated. A major part of the research was devoted to the study of an uncommon monolayer pattern that we term the nanostrand network. LB monolayers consisting of nanostrands have sometimes been reported in the literature, but are often coexistent with other morphologies, which is not useful for potential applications. We have determined the molecular parameters and experimental conditions that control this morphology, making it highly reproducible, and have proposed a novel mechanism for the formation of this morphology. In addition, we have shown that the use of high-boiling spreading solvents, not usually used for Langmuir film preparation, can improve the nanostrand order. By investigation of a wide range of PS-PVP’s with various block ratios and molecular weights, with and without PDP present, we have established the composition dependence of the main LB morphology types (planar, nanostrand, nanodot) and the influence of each type on spreading solution concentration. This led to an extensive discussion concerning the mechanisms of morphology formation, including kinetic, molecular association, and dewetting contributions. We have also shown that the isotherm plateau transition for nanodot-forming PS-PVP/PDP is related to an order–order transition that occurs simultaneously with PDP reorientation, both aspects being clearly observed by AFM. These studies also form the basis for the use of ultrathin PS-PVP/PDP films as templates. The ability to produce well-controlled nanopatterned films on various substrates has been demonstrated, and film stability has been verified. Removal of small molecules from the nanostructures has revealed the appearance of new substructure of interest for further study.

The understanding of self-assembly processes is important for fabrication of well-defined structures with new functionalities for applications in the area of biomedical sciences, material sciences and electronics. In this thesis, two types of self-assembly processes are described: (1) self-assembly of fullerene derivatives in water and (2) self-assembly on surfaces using layer-by-layer (LbL) approach. The various interactions and parameters involved in the self-assembly are detailed in the introductory chapter 1. The various internal parameters like molecular geometry, intramolecular and intermolecular forces that guides the self-assembly process of amphiphiles in water are discussed. The experimental procedures used in the present thesis for the fabrication of nanostructures via self-assembly approach are also described. In the later part of the chapter, the LbL technique for fabrication of thin films and microcapsules is reviewed where various interactions involved in the growth of LbL assembly are discussed. The effect of ionic strength and pH on the growth and property of LbL assemblies is elaborated. A brief discussion of the materials used in the thesis ‒ fullerene, bovine serum albumin (BSA) and nanocrystalline cellulose (NCC) is also provided The self-assembly behaviour of amphiphilic fullerene derivatives are described in chapter 2. Fullerene is anisotropically substituted with five polar hydroxyl groups using organo-copper reagent. The derivative can interact in water via the van der Waals and hydrophobic interactions of the fullerene moiety as well as the intermolecular hydrogen bonding among the hydroxyl groups and also with water. The penta-hydroxy fullerene derivative self-assembles in water as vesicular structures. The size of these vesicles can be varied by modifying the kinetics of self-assembly which was done by changing the rate of addition of non-solvent (water) to the solution of the fullerene derivative. In the second derivative, the hydroxyl groups are substituted with less polar methoxy groups. The penta-methoxy fullerene derivative cannot participate in inter-molecular hydrogen bonding formation unlike the penta-hydroxy derivative but there is possibility of hydrogen bond formation with water where oxygens on methoxy group can act as hydrogen bond acceptor. The penta-methoxy fullerene does not show any vesicle formation in water. The computational simulation studies were carried out on the two fullerene derivatives to understand the self-assembly behaviour of these two derivatives. Furthermore, the vesicle structures formed by the penta-hydroxy fullerene derivative are used for entrapment of hydrophobic polymer, poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) and also hydrophilic dye, Rhodamine B. In both the cases, fluorescence quenching is observed due to electron transfer reaction with fullerene and hence these fullerene vesicles can be used to study the effect of confinement on electron transfer reactions and other chemical dynamics. The layer-by-layer self-assembly approach for the fabrication of biopolymeric thin films and microcapsules is discussed in the chapters 3 to 6. The biocompatible nanoparticles and nanofibers were used as the components of the assembly. In chapter 3, we have described fabrication of thin film of bovine serum albumin (BSA) nanoparticles via LbL approach using biopolymer chitosan as the complementary polymer. The driving force for the assembly growth of the assembly was the electrostatic and complementary hydrogen bond formation between the two components. The idea of incorporating nanoparticles in the thin film was that the nanoparticles can act as reservoirs for functional materials. The films were loaded with anticancer drug doxorubicin and show pH dependent release of the drug. The various interactions involved in the LbL assembly of BSA nanoparticles and polymers were investigated towards understanding the growth mechanism of the assembly in chapter 4. The understanding of the interactions involved in the assembly formation is important in order to modify the conditions of the assembly for enhancing the growth. It is inferred from the study reported in this chapter that not only the interaction of nanoparticles with polymers but also the inter-particle interactions are important factors in determining the growth of LbL assembly of nanoparticles/polymers. The growth of the assembly is enhanced on minimizing the inter-particle repulsions, which was achieved in case of BSA nanoparticles by modifying the pH of the assembly. We also utilized the LbL self-assembly approach for the delivery of lipophilic drugs. The lipophilic drugs are difficult to administer in the body due to their poor water solubility and hence show poor pharmacokinetic profile. The methods for incorporating hydrophobic drugs in LbL assembled thin films and microcapsules are described in chapters 5 and 6. In chapter 5, hydrophobic molecules binding property of albumin has been exploited for solubilisation of a water-insoluble molecule, pyrene (model drug) and hydrophobic drug, curcumin, by preparation of non-covalent conjugates with BSA. The interaction with BSA provided negative zeta potential to the previously uncharged molecules and hence they can be incorporated in the LbL assembled thin films and microcapsules using electrostatic as well as hydrogen bonding interaction with biopolymer, chitosan. The fabrication of protein encapsulated stable microcapsules with hydrophobic molecules incorporated in the shell of the microcapsules has also been demonstrated. The microcapsules were further capable of loading hydrophilic molecules like Rhodamine B. Thus, this approach can be employed for fabrication of multi-agent carrier for hydrophobic and hydrophilic drugs as well as therapeutic macromolecules. In chapter 6, we have incorporated nanocrystalline cellulose (NCC) LbL assembled thin films and microcapsules. The assembly formed was porous in nature due to the nano-fibrous morphology of NCC. The nanoassemblies can act as potential drug delivery carrier, which has been demonstrated by loading anticancer drug doxorubicin, and a lipophilic drug, curcumin. Doxorubicin hydrochloride, the salt form of the drug, doxorubicin, has good water solubility and hence can be postloaded in the assembly by diffusion from its aqueous solution. In the case of curcumin, which has limited solubility in water, a stable aqueous dispersion of the drug was prepared via noncovalent interaction with NCC prior to incorporation in the LbL assembly. The interaction of various other lipophilic drugs with NCC was analysed computationally.

The understanding of self-assembly processes is important for fabrication of well-defined structures with new functionalities for applications in the area of biomedical sciences, material sciences and electronics. In this thesis, two types of self-assembly processes are described: (1) self-assembly of fullerene derivatives in water and (2) self-assembly on surfaces using layer-by-layer (LbL) approach. The various interactions and parameters involved in the self-assembly are detailed in the introductory chapter 1. The various internal parameters like molecular geometry, intramolecular and intermolecular forces that guides the self-assembly process of amphiphiles in water are discussed. The experimental procedures used in the present thesis for the fabrication of nanostructures via self-assembly approach are also described. In the later part of the chapter, the LbL technique for fabrication of thin films and microcapsules is reviewed where various interactions involved in the growth of LbL assembly are discussed. The effect of ionic strength and pH on the growth and property of LbL assemblies is elaborated. A brief discussion of the materials used in the thesis ‒ fullerene, bovine serum albumin (BSA) and nanocrystalline cellulose (NCC) is also provided The self-assembly behaviour of amphiphilic fullerene derivatives are described in chapter 2. Fullerene is anisotropically substituted with five polar hydroxyl groups using organo-copper reagent. The derivative can interact in water via the van der Waals and hydrophobic interactions of the fullerene moiety as well as the intermolecular hydrogen bonding among the hydroxyl groups and also with water. The penta-hydroxy fullerene derivative self-assembles in water as vesicular structures. The size of these vesicles can be varied by modifying the kinetics of self-assembly which was done by changing the rate of addition of non-solvent (water) to the solution of the fullerene derivative. In the second derivative, the hydroxyl groups are substituted with less polar methoxy groups. The penta-methoxy fullerene derivative cannot participate in inter-molecular hydrogen bonding formation unlike the penta-hydroxy derivative but there is possibility of hydrogen bond formation with water where oxygens on methoxy group can act as hydrogen bond acceptor. The penta-methoxy fullerene does not show any vesicle formation in water. The computational simulation studies were carried out on the two fullerene derivatives to understand the self-assembly behaviour of these two derivatives. Furthermore, the vesicle structures formed by the penta-hydroxy fullerene derivative are used for entrapment of hydrophobic polymer, poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) and also hydrophilic dye, Rhodamine B. In both the cases, fluorescence quenching is observed due to electron transfer reaction with fullerene and hence these fullerene vesicles can be used to study the effect of confinement on electron transfer reactions and other chemical dynamics. The layer-by-layer self-assembly approach for the fabrication of biopolymeric thin films and microcapsules is discussed in the chapters 3 to 6. The biocompatible nanoparticles and nanofibers were used as the components of the assembly. In chapter 3, we have described fabrication of thin film of bovine serum albumin (BSA) nanoparticles via LbL approach using biopolymer chitosan as the complementary polymer. The driving force for the assembly growth of the assembly was the electrostatic and complementary hydrogen bond formation between the two components. The idea of incorporating nanoparticles in the thin film was that the nanoparticles can act as reservoirs for functional materials. The films were loaded with anticancer drug doxorubicin and show pH dependent release of the drug. The various interactions involved in the LbL assembly of BSA nanoparticles and polymers were investigated towards understanding the growth mechanism of the assembly in chapter 4. The understanding of the interactions involved in the assembly formation is important in order to modify the conditions of the assembly for enhancing the growth. It is inferred from the study reported in this chapter that not only the interaction of nanoparticles with polymers but also the inter-particle interactions are important factors in determining the growth of LbL assembly of nanoparticles/polymers. The growth of the assembly is enhanced on minimizing the inter-particle repulsions, which was achieved in case of BSA nanoparticles by modifying the pH of the assembly. We also utilized the LbL self-assembly approach for the delivery of lipophilic drugs. The lipophilic drugs are difficult to administer in the body due to their poor water solubility and hence show poor pharmacokinetic profile. The methods for incorporating hydrophobic drugs in LbL assembled thin films and microcapsules are described in chapters 5 and 6. In chapter 5, hydrophobic molecules binding property of albumin has been exploited for solubilisation of a water-insoluble molecule, pyrene (model drug) and hydrophobic drug, curcumin, by preparation of non-covalent conjugates with BSA. The interaction with BSA provided negative zeta potential to the previously uncharged molecules and hence they can be incorporated in the LbL assembled thin films and microcapsules using electrostatic as well as hydrogen bonding interaction with biopolymer, chitosan. The fabrication of protein encapsulated stable microcapsules with hydrophobic molecules incorporated in the shell of the microcapsules has also been demonstrated. The microcapsules were further capable of loading hydrophilic molecules like Rhodamine B. Thus, this approach can be employed for fabrication of multi-agent carrier for hydrophobic and hydrophilic drugs as well as therapeutic macromolecules. In chapter 6, we have incorporated nanocrystalline cellulose (NCC) LbL assembled thin films and microcapsules. The assembly formed was porous in nature due to the nano-fibrous morphology of NCC. The nanoassemblies can act as potential drug delivery carrier, which has been demonstrated by loading anticancer drug doxorubicin, and a lipophilic drug, curcumin. Doxorubicin hydrochloride, the salt form of the drug, doxorubicin, has good water solubility and hence can be postloaded in the assembly by diffusion from its aqueous solution. In the case of curcumin, which has limited solubility in water, a stable aqueous dispersion of the drug was prepared via noncovalent interaction with NCC prior to incorporation in the LbL assembly. The interaction of various other lipophilic drugs with NCC was analysed computationally.

Simulations of various hydration levels of lamellar phase 23:2 Diyne PC were performed, and subsequent, serial docking simulations of a tyrosine monomer were replicated for each system in both hydrated and dehydrated states.
The goal was to evaluate how hydration impacts self-assembly and crystallization on the surface, and
whether or not these simulations, when run sequentially, could determine the answer. It was discovered that hydrated and dehydrated surfaces behave differently, and that
headgroup orientation plays a role in the initial docking and self-assembly process of the tyrosine monomer. It was also determined that potential energy as a sole metric
for determining whether or not a specific conformation of intermolecular orientation is not entirely useful, and docking scores are likely useful metrics in discriminating between conformations with identical potential energy values.

Nature is an excellent design that inspires scientists to develop smart systems. In the realm of separation technology, biological membranes have been an ideal model for synthetic membranes due to their ultrahigh permeability, sharp selectivity, and stimuliresponse. In this research, fabrications of bioinspired membranes from block copolymers were studied. Membranes with isoporous morphology were mainly prepared using selfassembly and non-solvent induced phase separation (SNIPS). An effective method that can dramatically shorten the path for designing new isoporous membranes from block copolymers via SNIPS was first proposed by predetermining a trend line computed from the solvent properties, interactions and copolymer block sizes of previously-obtained successful systems. Application of the method to new copolymer systems and fundamental studies on the block copolymer self-assembly were performed. Furthermore, the manufacture of bioinspired membranes was explored using (1) poly(styrene-b-4-hydroxystyrene-b-styrene) (PS-b-PHS-b-PS), (2) poly(styrene-bbutadiene- b-styrene) (PS-b-PB-b-PS) and (3) poly(styrene-b-γ-benzyl-L-glutamate) (PSb- PBLG) copolymers via SNIPS. The structure formation was investigated using smallangle X-ray scattering (SAXS) and time-resolved grazing-Incidence SAXS. The PS-b- PHS-b-PS membranes showed preferential transport for proteins, presumably due to the hydrogen bond interactions within the channels, electrostatic attraction, and suitable pore dimension. Well-defined nanochannels with pore sizes of around 4 nm based on PS-b- PB-b-PS copolymers could serve as an excellent platform to fabricate bioinspired channels due to the modifiable butadiene blocks. Photolytic addition of thioglycolic acid was demonstrated without sacrificing the self-assembled morphology, which led to a five-fold increase in water permeance compared to that of the unmodified. Membranes with a unique feather-like structure and a lamellar morphology for dialysis and nanofiltration applications were obtained from PS-b-PBLG copolymers, which exhibited a hierarchical self-assembled morphology with confined α-helical polypeptide domains. Our results suggest that bioinspired nanochannels can be designed via block copolymer self-assembly using classical methods of membrane preparation. Investigation of the membrane formation mechanism leads us to a better understanding of the design strategies for the development of self-assembled nanochannels from block copolymers. In further outlook, our research could give a contribution to the discovery of future generation materials for water purification and desalination, as well as biological separation.

Hydration is known to be crucial in biomolecular interactions including ligand binding and self-assembly. In our earlier studies we have shown the key role of water in stabilizing the specific parts of the collagen triple helix depending on the imino acid content. We further showed that the primary hydration shell around collagen could act as a lubricating layer aiding in collagen assembly. But key details on the structure and dynamics of water near protein surfaces and its role in protein-protein interactions remain unclear. In the current study we have developed a novel method to analyze hydration maps around peptides at 1-A resolution around three self-assembling lament systems with known structures, that respectively have hydrated (collagen), dry non-polar and dry polar (amyloid) interfaces. Using computer simulations, we calculate local hydration maps and hydration forces. We find that the primary hydration shells are formed all over the surface, regardless of the types of the underlying amino acids. The weakly oscillating hydration force arises from coalescence and depletion of hydration shells as two laments approach, whereas local water diffusion, orientation, or hydrogen bonding events have no direct effect. Hydration forces between hydrated, polar, and non-polar interfaces differ in the amplitude and phase of the oscillation relative to the equilibrium surface separation. Therefore, water-mediated interactions between these protein surfaces ranging in character from ‘hydrophobic’ to ‘hydrophilic,’ have a common molecular origin based on the robustly formed hydration shells, which is likely applicable to a broad range of biomolecular assemblies whose interfacial geometry is similar in length scale to those of the present study. In a related study through simulations we show that the rate of tissue optical clearing by chemical agents correlated with the preferential formation of hydrogen bond bridges between agent and collagen. Hydrogen bond bridge formation disrupts the collagen hydration layer and facilitates replacement by a chemical agent to destabilize the tertiary structure of collagens thereby reducing light scattering. This study suggests that the clearing ability of an alcohol not only depends on its molecular size, but also on the position of hydroxyl groups on its backbone.

Biological systems construct varieties of self-assembled architectures with incredible elegance and precession utilizing proteins as subunits to accomplish widespread functions. Inspired by natural systems, construction of artificial model systems with such sophistication and delicacy has become an intriguing field of research over the last two decades using so-called self-assembly process. Judiciously selected complementary building units encoded with specific chemical and structural information can be self-assembled into pre-programmed abiological architectures in a manner similar to biological self-assembly. In this regard, kinetically labile metal-ligand coordination has become an efficient and powerful protocol for the construction of highly intricate structures with specific topology and functionality due to its simple design principle, high bond enthalpy, and predictable directionality. Two-component self-assembly is very widely used methodology and easy to monitor. Recently, multi-component self-assembly has come up as an alternative and effective pathway to achieve complex architectures connecting more than two components in a single step. However, formation of selective single product from multicomponents is entropically unfavorable. Only a very few 3D architectures have been known, that are obtained from a mixture of ditopic and tri- or tetratopic donors with metal acceptors with or without employing templates. Development of template-free multicomponent architectures is still in its infancy. Strong tendency of Pd(II)/Pt(II) to attain square-planar geometry around the metal center and kinetically labile nature of Pd(II)/Pd(II)-N(pyridine) bonds made them chemists’ favourite to engineer desired supramolecular coordination architectures with structural resemblance to Platonic or Archimedean solids by employing symmetrical pyridyl donors due to their predictable directionality. In case of poly-imidazole donors, free rotation of C-N bond connecting imidazole and phenyl ring allows various dispositions of the donating nitrogen with respect to the aromatic backbone, and therefore, the structural topology of the architectures, made of poly-imidazole ligands becomes much more interesting as compared to symmetrical Platonic or Archimedean solids. The physico-chemical properties of self-assembled coordination cages depend on the structures of the complexes. Presence of large internal cavity surrounded by aromatic core, provides an excellent environment for the encapsulation of varieties of guest molecule or as nano-reactors for different organic transformations. Structural investigation in terms of packing interactions, solvent molecules, intermolecular channels can sometimes determine the property of such self-assembled materials as well. Presence of acidic water as well as H-bonded 3D-networks of water molecules in molecular pockets make them potential material for proton conduction. In addition, metal-ligand coordination offers opportunity to introduce new functionality through pre-synthetic modification of the building constituents to influence the property of the supramolecular systems. Incorporation of unsaturated ethynyl functionality attached to the heavy transition metal is expected to exhibit efficient luminescence due to the facile metal to ligand charge transfer (MLCT). Hence, the final assemblies can be employed as chemosensors for electron-deficient nitroaromatics, which are the chemical signature of many of the commercially available explosives. The present investigation is focused on design and construction of discrete, nanoscopic coordination cages with unusual structural topology employing mainly imidazole-based donors with Pd(II)/Pt(II) acceptors and their applications in catalysis, chemosensing, and proton conduction. CHAPTER 1 of the thesis provides a general introduction to self-assembly focusing on the importance and advantages of metal-ligand directional bonding approach towards the construction of supramolecular architectures with various structural topologies. This chapter also includes a brief review on the applications of such coordination cages in various fields especially as ‘molecular flask’ for the observation of unique chemical phenomena and unusual reactions. Part A of CHAPTER 2 describes the synthesis of a new hollow Pd6 water soluble cage [{(tmen)Pd}6(timb)4](NO3)12 (1) via two-component self-assembly of a triimidazole donor and 90° Pd(II) acceptor [tmen = N,N,N’,N’-tetramethylethylenediamine, timb = 1,3,5-tris(1-imidazolyl)benzene]. The assembly was successfully crystallized with a hydrophilic dianionic benzoquinone derivative (formed in situ by the decomposition of DDQ) as [{(tmen)Pd}6(timb)4](NO3)10()2(H2O)18 (3), and a hydrophobic sterically demanding aromatic aldehyde as [{(tmen)Pd}6(timb)4](NO3)12{()4a}2(H2O)27 (5a) [where 2H2 = 2,3-dichloro-5,6-dihydroxycyclohexa-2,5diene-1,4-dione, 4a = 1-pyrenecarboxaldehyde,  = exohedral and  = endohedral] to confirm the hydrophobic nature of the cavity. Experiments were carried out to show that the hydrophobic confined nanospace of the cage (1) catalyses the Knoevenagel condensation of a series of different aromatic monoaldehydes with active methylene compounds in ‘green’ aqueous medium. The Knoevenagel condensation reaction is basically a dehydration reaction because water is a by-product. So the presence of water should, in principle, promote the backward reaction as per Le Chatelier’s principle. In general, these reactions with organic substrates are not performed in water. However, difficulty has been overcome using hydrophobic cavity of the cage. It has also been established that the cavity of the cage also enhances the rate of Diels-Alder reaction of 9-hydroxymethylanthracene with N-phenylmaleimide/N-cyclohexylmaleimide. Figure 1. Catalytic Knoevenagel condensation and Diels-Alder reaction using hydrophobic cavity of the cage (1) in aqueous medium. Part B of CHAPTER 2 reports unique three-component self-assembly incorporating both tri- and tetra-topic donors. Until now, a very few 3D-architectures have been known that are obtained from self-assembly of ditopic and tri- or tetratopic donors with metal acceptors. Scheme 1. Three-component self-assembly of a Pd7 cage (1) from cis-blocked Pd(II) 90° acceptor (M), tri-imidazole (timb) and tetra-imidazole (tim) donors. Self-assembled multicomponent discrete architecture composed of both tri- and tetra-topic donors is yet to be reported due to difficulty in prediction of the final structure from the mixture of ligands having multiple donor sites. The first example of self-sorted Pd7 molecular boat [{(tmen)Pd}7(timb)2(tim)2](NO3)14(H2O)20 (1) [tmen = N,N,N’,N’-tetramethylethylenediamine, timb = 1,3,5-tris(1-imidazolyl)-benzene, tim = 1,2,4,5-tetrakis(1-imidazolyl)benzene] was synthesized via three-component self-assembly of cis-(tmen)Pd(NO3)2, tetra- (tim) and tri-topic donors (timb) in a 7:2:2 ratio. The cavity of this cage was also utilized as a nanoreactor for catalytic Knoevenagel condensations of a series of aromatic aldehydes with 1,3-dimethylbarbituric acid (e) and Meldrum’s acid (f) in aqueous media. CHAPTER 3 presents the results of an investigation on how simple variation of length and coordination mode of linear donors can self-discriminate into markedly different complex architectures, from Pd8 molecular swing [{(tmen)Pd}8(tim)2(bpy)4](NO3)16 (1) or [{(tmen)Pd}8(tim)2(stt)5](NO3)6 (2) to Pd6 molecular boat [{(tmen)Pd}6(tim)2(bpe/dpe/pin/dpb)2](NO3)12, (3/4/5/6). Also by enhancing denticity [bidentate to tridentate (ptp)] as well as introducing asymmetry, they self-sort into Pd7 molecular tent [{(tmen)Pd}7(tim)2(ptp)2](NO3)14 (7) by employing it in a self-assembly of cis-(tmen)Pd(NO3)2 and tetraimidazole (tim) donor [where tmen = N,N,N’,N’-tetramethylethylenediamine, bpy = 4,4’-bipyridyl, stt = sodium terephthalate, bpe = trans-1,2-bis(4-pyridyl)ethylene, dpe = 1,2-di(pyridin-4-yl)ethane, pin = N-(pyridin-4-yl)isonicotinamide, dpb = 1,4-di(pyridin-4-yl)benzene, ptp = 6'-(pyridin-4-yl)-3,4':2',4''-terpyridine, and tim = 1,2,4,5-tetrakis(1- imidazolyl)benzene]. In these cases, control of the geometrical principles and stereo-electronic preferences of the building units allowed the formation of such intricate architectures. Some of these assemblies represent first examples of such types of structures, and their formation would not be anticipated by taking into account only the geometry of the donor and acceptor building units. In addition to their direct structural confirmation using single crystal X-ray diffraction analysis, propensity of the assemblies (1 and 3) to form inclusion complexes with large guest like C60 in solution was also demonstrated by fluorescence quenching experiment. The high KSV values for both the assemblies 1 (1.0 × 10-5 M-1) and 2 (1.6 × 10-6 M-1) with C60 indicated the propensity of these assemblies to form complexes with C60 in solution. Furthermore, inspection of crystal packing of other five complexes (2 and 4 - 7) revealed the presence of water molecules H-bonded with NO3– (O-H···O=N) and 3D H-bonded networks of water in the intermolecular pockets. Interestingly, the present complexes (2 and 4 - 7) show high conductivity across low-humidity range at ambient temperature and achieve a conductivity of ~10-3 Scm-1 at 75% relative humidity and 296 K. These supra-molecular architectures represent a new generation of discrete materials that display high proton conductivity under ambient conditions with activation energy comparable to that of Nafion. Scheme 2. Exclusive formation of Pd8 molecular swings (1 and 2), Pd6 molecular boats (3-6), and Pd7 molecular tent (7) via self-sorting. CHAPTER 4 presents self-selection by synergistic effect of morphological information and coordination ability of the ligands through specific coordination interactional algorithms within dynamic supramolecular systems involving a tetratopic Pd(II) acceptor and three different pyridine- and imidazole-based donors (La - Lc) [La = 1,3-bis((E)-2-(pyridin-3-yl)vinyl)benzene, Lb = 1,3-di(1H-imidazol-1-yl)benzene, and Lc = tris(4-(1H-imidazol-1-yl)phenyl)amine]. Three different cages, ‘paddle wheel’ cluster Pd2(La)4(NO3)4 (2a), molecular barrel Pd3(Lb)6(NO3)6 (2b) and molecular sphere Pd6(Lc)8(NO3)12 (2c) were first synthesized via two-component self-assembly of a tetratopic Pd(II) acceptor (1) and individual pyridine- and imidazole-based donors (La - Lc). When all the four components were allowed to interact in a complex reaction mixture, only one out of three cages was isolated. The inherent dynamic nature of the kinetically labile coordination bond allows constitutional adaptation through component exchange in the competition experiment involving multiple constituents to self-organize into specific combination and thereby, achieve the thermodynamically most stable assembly. The preferential binding affinity towards a particular partner was also established by transforming a non-preferred cage to a preferred cage by the interaction with the appropriate ligand and thus, this represents the first examples of two-step cage-to-cage transformation through constitutional evolution of Figure 2. Cage-to-cage transformation from non-preferred cage to preferred cage upon treatment with appropriate ligand; and Nyquist plots of the complexes (2b and 2c) under 98% RH condition and ambient temparature. dynamic systems induced by both coordination ability and geometry of the ligand. Moreover, computational study further supported the fact that coordination interaction of imidazole moiety to Pd(II) is enthalpically more preferred compared to pyridine which drives the selection process. In addition, analysis of crystal packing of both the complexes (2b and 2c) indicated the presence of strong H-bonds between NO3- and water molecules; as well as H-bonded 3D-networks of water. Interestingly, both the complexes exhibit promising proton conductivity (10-5 to ca. 10-3 S cm-1) at ambient temperature under relative humidity of ~98% with low activation energy. CHAPTER 5 covers design and synthesis of new organometallic building block 1,3,5-tris(4-trans-Pt(PEt3)2I(ethynyl)phenyl)benzene (1) incorporating Pt-ethynyl functionality and [2 + 3] self-assembly of its nitrate analogue 1,3,5-tris(4-trans-Pt(PEt3)2(ONO2)(ethynyl)phenyl)benzene (2) with “clip” type bidentate donors (L1 – L3) separately afforded three trigonal prismatic architectures (3a – 3c), respectively (Scheme 3), Scheme 3. Schematic presentation of three different donors (L1 – L3) and a new planar tritopic acceptor (2) and their [3 + 2] self-assembly into trigonal prismatic architectures (3a - 3c). [L1 = N1,N3-di(pyridin-3-yl)isophthalamide; L2 = 1,3-bis((E)-2-(pyridin-3-yl)vinyl)benzene; L3 = 1,3-bis(pyridin-3-ylethynyl)benzene]. All these prisms were characterized and their shapes/sizes are predicted through geometry optimization employing molecular mechanics universal force field (MMUFF) simulation. The extended -conjugation including the presence of Pt-ethynyl functionality make them electron rich as well as luminescent in nature. As expected, cages 3b and 3c exhibit fluorescent quenching in solution upon addition of picric acid [PA], which is a common constituent of many explosives. Interestingly, the non-responsive nature of fluorescent intensity towards other electron-deficient nitro-aromatic explosives (NAEs) makes them promising selective sensors for PA with a detection limit deep down to ppb. Complexes 3b – c represent the first examples of molecular metallocages as selective sensors for picric acid. Furthermore, solid-state quenching of fluorescent intensity of the thin film of 3b upon exposure to saturated vapor of picric acid draws special attention for infield application.