This study aims synthesis of metal/polymer one dimensional nanostructures by micelle formation, reduction, and electrospinning route, and to analyze the morphological characteristics of composite nanofibers. The study was carried out in three main steps. First, the reverse micelle structures were established between the anionic surfactant and the metal ion. The surfactant acts as an agent to bind metal ions together so that the arrangements of metal ions can be controlled in the solution. As the surfactant concentration increases, reverse micelles grow and reverse wormlike micelle structures are observed. Wormlike micelles are elongated semi flexible aggregates which form a spherocylinder form repeating units. Metal ions are in the core and surrounded with the surfactant. The polymer attached to the wormlike structure acts as a shield and prevents phase separation in a hydrophilic medium. Different polymer and surfactant concentrations were tried to determine the optimum polymer and surfactant concentrations for reverse micelle formation. The size analyses of the reverse micelle structures were done by dynamic light scattering technique. In the second step, metal ions in the micelles were reduced by using hydrazine hydrate to obtain metal cores in the center of wormlike micelles. Finally, electrospinning was carried at room temperature and in air atmosphere. The characterization of nano composites was done by Scanning Electron Microscopy. It was found that the size of the reverse micelle structures affects the distribution of metal nano partices in polymer nano fibers. In order to distribute the metal nano particles homogeneously, the optimum size of reverse wormlike micelles was found to be between 420 and 450 nm.

In dieser Arbeit wurde die gegenseitige Beeinflussung von mizellaren Strukturen und Photodimerisierung von Cumarinderivaten untersucht. Als Mizellbildner wurden das kationische Cetyltrimethylammoniumbromid (CTAB) und das nicht-ionische Triton X-100, als Solubilisate Cumarinderivaten verwendet. Es wurden rheologische, thermodynamische und photochemische Untersuchungen durchgeführt. Die Viskosität der beiden Tensidsysteme steigt mit zunehmender Solubilisatkonzentration je nach Cumarinderivat unterschiedlich stark an. Dabei zeigten 6-Alkylcumarine als Solubilisate die größten "rheologischen Effekte". Die Photodimerisierung der solubilisierten Cumarine führte zu einem weiteren Anstieg oder zu einer Abnahme der Viskosität der CTAB- und Triton X-100-Lösungen - "photorheologischer Effekt". In Abhängigkeit von der Konzentration werden Strukturänderungen der mizellaren Aggregate induziert, die teilweise zu drastischen Änderungen der makroskopischen Eigenschaften der Tensidlösungen-Lösung führen. Die Photodimerisierung fungiert dabei als "large-response-trigger". Die Kettenlänge der solubilisierten 6-Alkylcumarine beeinflusst das Fießverhalten der CTAB-Lösungen und Triton X-100-Lösungen. Mit zunehmender Kettenlänge steigt die Viskosität der beiden Tensidlösungen zunächst an, um dann bei noch längeren Ketten wieder abzunehmen. In beiden Tensidsystemen liegt der Maximalwert bei 6-Oktylcumarin. Der Photodimerisierung beeinflusst die Viskosität der beiden Tensid-Systeme unterschiedlich. In CTAB-Lösungen in Anwesenheit von kürzeren Alkylcumarinen steigt die Viskosität mit der Photodimerisierung weiter. Ab Pentylcumarin nimmt die Viskosität nach der Photodimerisierung jedoch ab. Im Triton X-100 System ist der photorheologische Effekt dagegen stets positiv. Thermodynamische Untersuchungen zeigen eine Korrelation mit dem rheologischen Effekt: Je größer die Viskosität, desto negativer sind Enthalpie- und Entropiedifferenzen bei der Bildung der mizellaren Aggregate. Die Ergebnisse legen als Ursache für die Viskositätseffekte Unterschiede in der Ausdehnung der Hydratwasserschicht der Mizellen nahe. Bei der photochemischen Untersuchungen wurden mit Hilfe von NMR-Spektroskopie und Kristallstrukturanalyse die isomeren Produkte der Photodimeriserung von Cumarinderivaten charakterisiert und die Produktverteilung unter verschiedenen Bedingungen ermittelt. In CTAB-Lösung konnte eine Möglichkeit Steuerung der Selektivität der Produktbildung gefunden werden: Lange 6-Alkylsubstituenten (ab 6-Propylcumarin) steuern zu Anti- und zu KK-Dimeren, während bei kurzen Ketten bzw. beim unsubstituierten Cumarin mehr Syn- und KS-Dimere gebildet werden. Bei dem im Detail untersuchten 6-Methylcumarin steigt die relative Quantenausbeute mit fallender Temperatur, abnehmender Konzentration und mit Zugabe des Triplettsensibilisators Benzophenon. In Gegenwart des Sensibilisators entsteht vermehrt das Anti-KK-Dimer, was darauf schließen lässt, dass dieses aus dem Triplett-Zustand gebildet wird. In ionischer mizellarer Lösung CTAB bilden sich bevorzugt Syn-Dimere. In unpolaren Lösungsmitteln entsteht nur Anti-KK, während in polaren Lösungsmitteln auch kleine Mengen Syn-Dimere gebildet werden. Die Lewis-Säure BF3 beschleunigt die Photodimerisierung deutlich und steuert zu Syn-KS.

In der vorliegenden Arbeit werden off-lattice Monte-Carlo-Simulationen von Systemen einfacher Tensidmodelle präsentiert. Die verwendeten Modellmoleküle bestehen aus einem hydrophilen Kopfsegment und zwei hydrophoben Kettensegmenten. Zwischen den Segmenten wurden square-well-Wechselwirkungen benutzt, um den Hydrophoben Effekt und andere Wechselwirkungen zu simulieren. Die Aggregation der Tensidmodelle wurde im Lösungsvolumen und an Feststoffoberflächen untersucht. In der Lösung wurden Kugelmicellen, Wurmmicellen, Bischichten und Vesikel beobachtet. Die Struktur der Aggregate wird bei der Adsorption an Feststoffoberflächen mit niedriger oder mittlerer Adsorptionsenergie nicht grundlegend verändert. An Oberflächen wurden in Abhängigkeit vom Verhältnis der Adsorptionsenergie zur Stärke des Hydrophoben Effektes verschiedene Strukturen der adsorbierten Schichten beobachtet. Eigenschaften der adsorbierten Aggregate wurden bei unterschiedlichen Oberflächenkonzentrationen ermittelt.

The goal of this project was to develop a non-toxic amphiphilic diblock copolymer nanoparticulate drug delivery system that will solubilize paclitaxel (PTX) and retain the drug in plasma. Methoxy poly(ethylene glycol)-block-poly(ε-caprolactone) (MePEG-b-PCL) diblock copolymers loaded with PTX were characterized and their physicochemical properties were correlated with their performance as nanoparticulate drug delivery systems. A series of MePEG-b-PCL was synthesized with PCL blocks ranging from 2-104 repeat units and MePEG blocks of 17, 44 or 114 repeat units. All copolymers were water soluble and formed micelles except MePEG₁₁₄-b-PCL₁₀₄, which was water insoluble and formed nanospheres. Investigation of the effects of block length on the physicochemical properties of the nanoparticles was used to select appropriate copolymers for development as PTX nanoparticles. The critical micelle concentration, pyrene partition coefficient and diameter of nanoparticles were found to be dependent on the PCL block length. Copolymers based on a MePEG molecular weight of 750 g/mol were found to have temperature dependent phase behavior. Relationships between the concentration of micellized drug and the compatibility between the drug and core-forming block, as determined by the Flory-Huggins interaction parameter, and PCL block length were developed. Increases in the compatibility between PCL and the drug, as well as longer PCL block lengths resulted in increased drug solubilization. The physicochemical properties and drug delivery performance characteristics of MePEG₁₁₄-b-PCL₁₉ micelles and MePEG₁₁₄-b-PCL₁₀₄ nanospheres were compared. Nanospheres were larger, had a more viscous core, solubilized more PTX and released it slower, compared to micelles. No difference was seen in the hemocompatibility of the nanoparticles as assessed by plasma coagulation time and erythrocyte hemolysis. Micellar PTX had an in vitro plasma distribution similar to free drug. The majority of micellar PTX associated with the lipoprotein deficient plasma fraction (LPDP). In contrast, nanospheres were capable of retaining more of the encapsulated drug with significantly less PTX partitioning into the LPDP fraction. In conclusion, although both micelles and nanospheres were capable of solubilizing PTX and were hemocompatible, PTX nanospheres may offer the advantage of prolonged blood circulation, based on the in vitro plasma distribution data, which showed that nanospheres retained PTX more effectively.

The goal of this project was to develop a non-toxic amphiphilic diblock copolymer nanoparticulate drug delivery system that will solubilize paclitaxel (PTX) and retain the drug in plasma. Methoxy poly(ethylene glycol)-block-poly(ε-caprolactone) (MePEG-b-PCL) diblock copolymers loaded with PTX were characterized and their physicochemical properties were correlated with their performance as nanoparticulate drug delivery systems. A series of MePEG-b-PCL was synthesized with PCL blocks ranging from 2-104 repeat units and MePEG blocks of 17, 44 or 114 repeat units. All copolymers were water soluble and formed micelles except MePEG₁₁₄-b-PCL₁₀₄, which was water insoluble and formed nanospheres. Investigation of the effects of block length on the physicochemical properties of the nanoparticles was used to select appropriate copolymers for development as PTX nanoparticles. The critical micelle concentration, pyrene partition coefficient and diameter of nanoparticles were found to be dependent on the PCL block length. Copolymers based on a MePEG molecular weight of 750 g/mol were found to have temperature dependent phase behavior. Relationships between the concentration of micellized drug and the compatibility between the drug and core-forming block, as determined by the Flory-Huggins interaction parameter, and PCL block length were developed. Increases in the compatibility between PCL and the drug, as well as longer PCL block lengths resulted in increased drug solubilization. The physicochemical properties and drug delivery performance characteristics of MePEG₁₁₄-b-PCL₁₉ micelles and MePEG₁₁₄-b-PCL₁₀₄ nanospheres were compared. Nanospheres were larger, had a more viscous core, solubilized more PTX and released it slower, compared to micelles. No difference was seen in the hemocompatibility of the nanoparticles as assessed by plasma coagulation time and erythrocyte hemolysis. Micellar PTX had an in vitro plasma distribution similar to free drug. The majority of micellar PTX associated with the lipoprotein deficient plasma fraction (LPDP). In contrast, nanospheres were capable of retaining more of the encapsulated drug with significantly less PTX partitioning into the LPDP fraction. In conclusion, although both micelles and nanospheres were capable of solubilizing PTX and were hemocompatible, PTX nanospheres may offer the advantage of prolonged blood circulation, based on the in vitro plasma distribution data, which showed that nanospheres retained PTX more effectively.

京都大学 / 新制・課程博士 / 博士(工学) / 甲第23921号 / 工博第5008号 / 新制||工||1782(附属図書館) / 京都大学大学院工学研究科高分子化学専攻 / (主査)教授 古賀 毅, 教授 中村 洋, 教授 竹中 幹人 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

The synthesis of well-defined polymer nanoparticles will have immediate applications in the biomedical industry as nanocontainers for the controlled delivery and release of water insoluble drugs. The ability to control molecular weight, particle morphology and chemical functionality and to obtain polymeric nanoparticles with narrow molecular weight and particle size distributions is paramount for their application-specific design. Two synthetic approaches were investigated in the synthesis of well-defined polymer nanoparticles, emulsion polymerization and self assembly. The successful implementation of Reversible Addition-Fragmentation Chain Transfer (RAFT) in emulsion polymerization was the first challenge faced when controlling nanoparticle molecular weight and size. Initially we showed that successful ‘living’ emulsion polymerizations of styrene could be carried out using a non-ionic surfactant. The success was achieved when preparing polymers of low molecular weight (5 and 9 K targeted Mn’s with polydispersities (PDIs) below 1.2). Deviation from ideal ‘living’ behavior occurred when targeting Mn’s greater than 20 K (at 100 % conversion). The ‘degassing technique’ was then investigated as an avenue to generate stable polystyrene nanoparticles by emulsion polymerization without the addition of surfactant (residual surfactant can result in detrimental effects on product quality). The polymerization of this emulsion system in the presence of a low reactive RAFT agent was ‘living’ in nature. In the presence of a high reactive RAFT agent the emulsion system showed ‘living’ nature, however, secondary nucleation occurred, which resulted in broad molecular weight distribution (MWD). Thus, the emulsion polymerization approach to preparing well-defined polymer nanoparticles was giving less than desirable results. An alternative method to prepare polymer nanoparticles with controlled chemical composition and morphology is to self assemble pre-synthesized block copolymers in water. This approach has several significant advantages over the emulsion systems: (i) all polymer chains are of near uniform chain length and chemical composition, (ii) the ratio between the hydrophobic and hydrophilic polymers can easily be controlled, (iii) chemical functionality can be located in different morphological regions, (iv) a wide range of 3-dimensional structures apart from spheres can be prepared (i.e. rods and vesicles), and (v) additives such as surfactant, stabilizers and residual monomer usually found after an emulsion polymerization are not required in the self assembly methodology. These advantages justify our shift in strategy. The only disadvantage of the self assembly process is that one cannot reach high weight fractions of polymer in water and is usually limited to below 2 wt-%, where as emulsion polymerizations can allow weight fractions of polymer close to 50 wt-%. Well-defined amphiphilic 4-arm star polyacrylic acid-block-polystyrene (PAA-b-PSTY) copolymers, prepared by RAFT solution polymerization, were dispersed in water to form core-shell micelles, in which the shell consisted of tethered PAA loops. The entropic penalty for having such loops resulted in a less densely packed PSTY core when compared to linear diblock copolymers of the same arm length. The surface of the shell was irregular due to the tethering points, but when cleaved the PAA chains extended to form a regular and relatively uniform corona. Controlling the polymer architecture enabled the synthesis of polymer micelles with tethered PAA loops, which could be opened to form uniform corona when desired. Three-miktoarm star and dendrimers with miktoarms consisting of PSTY, polytert-butyl acrylate (PtBA), polymethyl acrylate (PMA) and PAA were then synthesized using a combination of Atom Transfer Radical Polymerization (ATRP) and Huisgen 1,3-dipolar cycloaddition ‘click’ reactions. In all reactions, the stars and dendrimers were well-defined with PDIs lower than 1.09. This was the first step in the synthesis of well-defined highly ordered polymer structures. The synthesis of such structures demands high level of purity at each synthetic step eliminating the possibility of side reactions, which as of consequence lowers product yields. The synthesis and use of reactive solid supports to remove excess linear polymer to increase the yields of polymeric 3-arm stars and dendrimers was employed. These supports are a cheap approach to scavenge polymeric species with either azido or alkynyl functionality, after which the solid support can be filtered away from the product. These supports aided the synthesis of 3rd generation polymeric dendrons and dendrimers consisting of homopolymer PSTY with either solketals or alcohols at the periphery, diblock PSTY and PtBA, and amphiphilic diblock. The methodology used to construct these structures was a combination of ATRP to produce linear polymers with telechelic functionality, with the subsequent use of this functionality to join the polymers together via ‘click’ reactions. Micellization of the amphiphilic structures in water produced polymer nanoparticles of uniform size. The dendrimer nanoparticles were 18 nm in diameter, consisting of 19 individual dendrimers. The dendrimers most probably have no mutual interpenetration and thus pack uniformly to form the micelles. The dendron nanoparticles were 21 nm with an aggregation number of 43 dendrons per micelle, which suggests they form cone-like structures and self-assemble to form crew-cut micelles. Using a convergent approach polymer structures with unprecedented chemical diversity (hydrophobic or amphiphilic) and complexity (G2 miktoarm dendrimers with a degradable core) consisting of PSTY, PMA, PtBA and PAA were then synthesized with high purity using copper wire as the ‘click’ catalyst.

Zugl.: Karlsruhe, Univ., Diss., 2007

Techn. Universiẗat, Diss., 2003--Berlin.

Nesta dissertação avaliou-se o uso de óleos vegetais na descontaminação \"ex-situ\" de solo contaminado por compostos policíclicos aromáticos (PAHs). O processo trata solo com microemulsão (µE) formada por água (A) /tensoativo não-iônico comercial (S) C9/11EO4 /\"óleo\" (O), sendo este ésteres metílicos dos óleos de coco (CME), babaçu (BME), e fração saturada (SME) e insaturada (LME) do azeite de dendê. Estudamos os diagramas de fase dos sistemas acima, em função de ? = O/(A+O) e ? = S/(S+A+O), em peso. Os sistemas pseudo- ternários foram estudados em função da temperatura, T para diferentes ? (? constante) e ? (? constante). Os diagramas de fase foram qualitativamente similares àqueles obtidos para sistemas com água /alcano /tensoativo não- iônico homogêneo. Eles apresentaram o assim chamado diagrama tipo \"peixe\". O \"corpo do peixe\" é trifásico enquanto que sua \"cauda\" é monofásica e isotrópica. As duas áreas se encontram na Temperatura de balanço hidrofílico- lipofílico, THLB (Schubert e Kaler, 1996). As principais diferenças obtidas entre os diagramas baseados em óleos vegetais e os de sistemas água/ alcano/ tensoativo não iônico homogêneo foram: a) Para T em função de ?, o diagrama tipo \"peixe\" é extremamente distorcido para cima, e seu \"corpo\" (área trifásica) é muito reduzido; b) Para T em função de ? (diagrama do \"canal\"), a fase isotrópica ocorre apenas para ? maior ou igual a 0,5. As microestruturas das monofases isotrópicas foram caracterizadas por reologia, difração de raios X e espalhamento quasi-elástico de luz (QELS). A baixa viscosidade e o comportamento Newtoniano destes líquidos mostraram que estes não contém cristais líquidos cúbicos. Esta conclusão foi corroborada por medidas de difração de raios X, que não apresentaram padrões de difração característicos de estruturas organizadas a longa distância. Os coeficientes de difusão das monofases foi medido por QELS. Isto indicou que as soluções monofásicas são compostas por µEs bicontínuas ou água/óleo (A/O), com THLB=37,5ºC para CME e BME e 42,5ºC para SME e LME, respectivamente. Testes indicaram que estrutura da µE, razão µE/solo, e tempo de contato são variáveis importantes na extração. A quantidade de µE deve ser suficiente para molhar toda a superfície do solo, sem causar redeposição dos PAHs. A melhor razão µE/solo foi 6. As µEs bicontínuas foram agentes descontaminantes mais eficientes que µEs A/O, provavelmente por dessorverem PAH do solo pelo decréscimo da tensão interfacial. A descontaminação pelas µEs bicontínuas foi 35% mais eficiente que a extração por tolueno em Soxhlet por 6h (?=0,5 e 0,6, tempo de contato 3h à THLB, razão µE/solo=6). O éster usado influencia principalmente a formação e estabilidade da µE. Depois da descontaminação, o solo foi lavado com água e sua biodisponibilidade foi avaliada pela medição da densidade de carga. Esta aumentou em 63%, 86%, 100% e 162% para as amostras que foram tratadas com µEs com CME, SME, LME e BME, respectivamente (µEs bicontínuas, ?=0,5 e ?=0,3). / In the present project, we were interested in assessing the use of Brazilian vegetable oils in the \"ex-situ\" decontamination of soils from polycyclic aromatic hydrocarbons (PAHs). In this process, contaminated soil is treated with a microemulsion (µE) composed of water (W) /commercial non-ionic surfactant (S) C9/11EO4 /oil (O). The latter term refers to the methyl esters of coconut oil (CME), babaçu oil (BME), and the saturated (SME), and unsaturated (LME) fractions of palm oil. Phase diagram of the above mentioned systems were studied. We used weight fractions, ? = (O / W + O) e ? = (S / S + W + O). The pseudo-ternary systems were then studied as a function of temperature, at different ? (? constant) and ? (? constant). The phase diagrams were qualitatively similar to those previously obtained for systems of water/alkane/homogeneous non-ionic surfactant. These show the so-called \"fish\" type phase diagram. The fish \"body\" is triphasic whereas its \"tails\" is monophasic and isotropic. Both areas meet at the so-called hydrophilic-lipophilic temperature, THLB (Schubert and Kaler, 1996). The following are the main differences between the vegetable oil-based phase diagrams and those of homogeneous component systems: a) The fish diagram is severely skewed upward, and its body area is much reduced; b) In the temperature versus ? channel\" phase diagram; the monophasic region exists only at ? equal or above 0.5. The microstructures of the monophasic regions were studied by rheology, X ray diffraction, and quasi-elastic light scattering, QELS. The low viscosity and Newtonian behavior of these liquids shows that they do not contain cubic liquid crystals. This conclusion was corroborated by X ray diffraction measurements, which did not show diffraction patterns characteristic of systems of long-range structural order. The diffusion coefficients of the species involved were measured with QELS. These indicated that monophasic solutions are composed of bicontinuous and W/O microemulsions, whose THLB, is 37.5 ºC for CME, BME, and 42.5 ºC for SME and LME, respectively. The structure of the µE employed, µE/soil ratio, and contact time are important extraction variables. The amount of the µE should be sufficient to wet the surface of the soil, without causing PAHs redeposition. The optimum ratio was 6. Bicontinuous µEs were more efficient decontaminators than W/O microemulsions probably because they desorb PAH from soil by decreasing the associated interfacial tension. Decontamination by the former µEs was 35% more efficient than by hot toluene (6 hours, Soxhlet). After decontamination, the soil was washed with water, and its bioavailability assessed by measuring its charge density. Relative to the original soil, the charge density of decontaminated soil increased by 63%, 86%, 100% and 162%, for washed samples, which were decontaminated with µEs of CME, SME, LME and BME, respectively (µEs BI; ? = 0.5 e ? = 0.3).