CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / Os BTEX (benzeno, tolueno, etilbenzeno e xilenos) constituem preocupaÃÃo particular pela sua toxicidade, sendo formados no meio ambiente pela oxidaÃÃo incompleta dos combustÃveis fÃsseis, os quais contaminam a atmosfera; pelo descarte de efluentes industriais, por derrames durante o transporte e por vazamentos em postos de combustÃveis, contaminando o solo e a Ãgua, e acumulando-se, principalmente, nas Ãguas subterrÃneas. Tecnologias convencionais e avanÃadas vÃm sendo utilizadas na tentativa de tratamento e remediaÃÃo de Ãreas contaminadas por BTEX. As zeÃlitas englobam grande nÃmero de minerais naturais e sintÃticos que apresentam caracterÃsticas comuns. O grande potencial de aplicaÃÃo das zeÃlitas sintÃticas na Ãrea ambiental à mundialmente comprovado. Neste trabalho, avaliou-se a modificaÃÃo superficial da zeÃlita sintÃtica Y com surfactante HDTMA-Br e sua aplicaÃÃo para a remoÃÃo de BTEX de amostras aquosa. Foi realizado estudo da capacidade de troca catiÃnica (CTC) da zeÃlita e em seguida foram realizadas trÃs modificaÃÃes da zeÃlita com surfactante, correspondente a 50% da CTC, 100% da CTC e 200% da CTC. A zeÃlita sintÃtica e as modificadas foram submetidas a teste de adsorÃÃo dos BTEX. Os resultados mostraram que dentre as zeÃlitas modificadas, a ZMS-100 se mostrou mais eficiente na remoÃÃo dos BTEX. Este material foi utilizado para estudo de cinÃtica e isoterma de adsorÃÃo. O estudo de cinÃtica indicou que o equilÃbrio de adsorÃÃo multicomponente foi atingido em 6 horas e segue cinÃtica de pseudo-segunda ordem. Foram utilizados os modelos de Langmuir, Freundlich, Redlich-Peterson e Temkin para avaliar o mecanismo de adsorÃÃo dos BTEX pela ZMS-100. O modelo de Temkin foi adequado para todos os BTEX em um sistema multicomponente e os valores de capacidade de adsorÃÃo mÃxima foram de 175, 32; 164,58; 162,22; 152,41; 150,42 mg/g para m,p-xilenos, o-xileno, etilbenzeno, tolueno e benzeno, respectivamente. Foi realizado estudo de ciclos de regeneraÃÃo do material em batelada e os resultados mostraram que o adsorvente sà pode ser utilizado para um ciclo de adsorÃÃo na remoÃÃo do benzeno, para os outros componentes à possÃvel realizar quatro ciclos de adsorÃÃo. / BTEX (benzene, toluene, ethylbenzene and xylenes) are organic compounds of particular concern due to their toxicity. BTEX occur in the environment as products of incomplete oxidation of fossil fuels, thus polluting the atmosphere. Also, the disposal of industrial effluents, oil spills, and fuels leaks at gas stations are sources of BTEX contamination in soil and water, resulting in their accumulation mainly in groundwater. Conventional and advanced technologies have been used for treatment and remediation of contaminated areas. Zeolites include many natural and synthetic minerals that have characteristics in common. The potential application of synthetic zeolites in the environmental field has been reported worldwide. In this work, surface modification of synthetic zeolite Y by Hexadecyltrimethylammonium (HDTMA-Br) was studied, as well as its application for removal of BTEX from aqueous solution. The zeolite cation exchange capacity (CEC) was evaluated and three modifications of the zeolite with surfactant HDTMA-Br were carried out, with results corresponding to 50%, 100%, and 200% of CEC. The results of BTEX adsorption experiments onto both synthetic and modified zeolites showed that the ZMS-100 was the most efficient modified zeolite for BTEX removal. Adsorption isotherms and kinetics study of this material were carried out. Kinetics study indicated that multicomponent adsorption equilibrium was reached in 6 hours and followed pseudo-second order kinetics. Langmuir, Freundlich, Redlich-Peterson and Temkin models were used to evaluate the adsorption capacity of BTEX by ZMS-100. Temkin model was found to be suitable all BTEX in a multicomponent system, and maximum adsorption capacities of 175, 32, 164.58, 162.22, 152.41, and 150.42 mg g-1 were observed for m-xylene, p-xylene, o-xylene, ethylbenzene, toluene and benzene, respectively. Regeneration cycles of the zeolite were also performed and the results showed that the adsorbent can be used only for one adsorption cycle for the removal of benzene, while for the other BTEX up to four regeneration cycles can be achieved.

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2017-06-09T15:51:35Z No. of bitstreams: 2 Tese - Fernanda Aparecida de Oliveira Peixoto - 2015.pdf: 1346302 bytes, checksum: 7ffcffc54a65cec4c0a8986361b2cfb2 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2017-06-09T15:51:55Z (GMT) No. of bitstreams: 2 Tese - Fernanda Aparecida de Oliveira Peixoto - 2015.pdf: 1346302 bytes, checksum: 7ffcffc54a65cec4c0a8986361b2cfb2 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-06-09T15:51:55Z (GMT). No. of bitstreams: 2 Tese - Fernanda Aparecida de Oliveira Peixoto - 2015.pdf: 1346302 bytes, checksum: 7ffcffc54a65cec4c0a8986361b2cfb2 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2015-08-07 / Despite the improvement in survival of premature infants, there was no progress in the incidence of bronchopulmonary dysplasia, especially in the last 20 years. Systemic corticosteroids, which has always been a therapeutic option, fell into disuse because of its adverse effects on the neurological development of premature infants and other routes of admistration have been researched for use of corticosteroids. Budesonide, which is an inhaled steroid, has been studied in an attempt to prevent bronchopulmonary dysplasia. The objectives of this study were to determine if the intratracheal instillation of budesonide with surfactant, improved lung performance, prevents chronic lung disease and reduces mortality in premature infants with minimal adverse effects. This is a clinical trial, blind and randomized 90 preterm infants who required prophylaxis or early rescue therapy with surfactant: 45 were randomized in the treated group (0.25 mg/kg of budesonide and 100 mg/kg surfactant) and 45 in the control group (100 mg/kg of surfactant). The evaluated final outcomes were mortality and bronchopulmonary dysplasia. Although the treatment group has shown better results than the control group, in both cases, mortality (10x15) and bronchopulmonary dysplasia at 36 weeks corrected gestational age (8/35 x 10/32), there was no significant statistical difference (p = 0.501 and p = 0.571). No clinically significant adverse events were observed in the study. The study concludes that, despite not having been demonstrated statistically significant difference in your results, we can not rule out the benefits of budesonide instilled into the trachea through the surfactant. Other randomized and multicenter studies should be encouraged. / Apesar da melhora na sobrevida dos recém-nascidos prematuros, não houve progresso em relação à incidência da displasia broncopulmonar, sobretudo nos últimos 20 anos. O corticoide sistêmico, que sempre foi uma opção terapêutica, entrou em desuso devido aos seus efeitos adversos no desenvolvimento neurológico dos prematuros. Outras vias têm sido pesquisadas para a utilização do corticoide. A budesonida, que é um esteroide de uso inalatório, tem sido estudada na tentativa de prevenir a displasia broncopulmonar. Os objetivos deste estudo foram determinar se a instilação intratraqueal de budesonida, por meio do surfactante, melhora o desempenho pulmonar, previne a doença pulmonar crônica e reduz a mortalidade em prematuros, com o mínimo de efeitos adversos possíveis. Trata-se de um ensaio clínico, cego e randomizado com 90 recém-nascidos prematuros que necessitaram de profilaxia ou de terapia de resgate precoce com surfactante: 45 foram randomizados no grupo tratado (0,25 mg/kg de budesonida e 100 mg/kg de surfactante) e 45 no grupo controle (100 mg/kg de surfactante). Os desfechos finais avaliados foram mortalidade e displasia broncopulmonar. Embora o grupo de tratamento tenha mostrado resultados melhores do que o grupo de controle, tanto para a mortalidade (10x15) quanto para displasia broncopulmonar avaliada com 36 semanas de idade gestacional corrigida (8/35 x 10/32), não houve diferença estatística significativa (p = 0,501 e p = 0,571). Nenhum evento adverso clinicamente significativo foi observado no estudo. O estudo conclui que, apesar de não ter sido demonstrado nenhuma diferença estatística significativa em seus resultados, não se pode descartar os benefícios da budesonida instilada na traqueia por meio do surfactante. Outros estudos randomizados e multicêntricos devem ser encorajados.

O monocloroacetato de sódio (MCAS) e o dicloroacetato de sódio (DCAS) são compostos tóxicos e irritantes ao ser humano e nocivos ao meio ambiente, sendo impurezas indesejáveis na cocoamido propil betaína (CAPB), que é um surfactante anfótero utilizado em produtos de consumo dos segmentos cosmético e domiciliar. Diante dos requisitos de concentração em nível de mg/kg exigidos pelos órgãos reguladores de saúde do governo, tornou-se mandatório o emprego de metodologia com limite de quantificação, precisão e exatidão adequados aos rígidos controles de processo pelos fabricantes da CAPB, bem como, dispor de técnicas convencionais com poder de resolução e proficiência pelo controle de qualidade e neste contexto inseriu-se a cromatografia a gás. Neste estudo foram estabelecidos os procedimentos analíticos que definiram as melhores condições para identificar e quantificar as impurezas MCAS e DCAS na matriz CAPB por meio da cromatografia a gás. A preparação das amostras consistiu da derivação das impurezas MCAS e DCAS a ésteres etílicos e a extração líquido-líquido em hexano para separar dos demais constituintes da matriz. Os modos de detecção acoplados à cromatografia a gás foram a ionização pela chama (GC/FID), a captura de elétrons (GC/ECD) e a espectrometria de massas (GC/MS). A validação comprovou que as metodologias são lineares entre 4 e 50 mg/kg com recuperação de 70 a 120%, apresentam limites de quantificação inferiores a 10 mg/kg e produziram médias e incertezas similares na amostra examinada, constituindo-se alternativas para a determinação de cloroacetatos em betaínas. / The sodium monochloroacetate (MCAS) and the sodium dichloroacetate (DCAS) are toxic and irritating compounds to humans and harmful to the environment, being undesirable impurities in cocoamidepropyl betaine (CAPB), which is a amphoteric surfactant used in consumer products of cosmetic and household segments. Considering the content requirements at level mg/kg defined by governmental health agency, became mandatory the use of analytical methods with appropriate precision, accuracy and quantification limit to rigid process controls by CAPB manufacturers, as well as, to have available conventional techniques with good resolution and proficiency for quality control staff and in this context was inserted the gas chromatography. In this study, the analytical procedures were established to define the best conditions to identify and quantify the impurities MCAS and DCAS in CAPB matrix by gas chromatography. The sample preparation consisted of MCAS and DCAS derivation to ethyl esters and liquid-liquid extraction in hexane to separate them from the other constituents of matrix. The detection modes coupled to gas chromatography were the flame ionization (GC/FID), electron capture (GC/ECD) and mass spectrometry (GC/MS). The validation ensured that the methodologies are linear between 4 and 50 mg/kg with recovery 70 to 120%, presents quantification limits less than 10 mg/kg and produced similar averages and uncertainties in the examined sample, constituting an alternative for determination of chloroacetates in betaines.

Abstract Respiratory distress syndrome (RDS) is a disease characterized by neonatal respiratory failure. It is principally caused by a deficiency of pulmonary surfactant, which is a lipoprotein mixture essential for reducing surface tension at the air-liquid interface of the alveolus. Prematurity is the major risk factor predisposing to RDS. Several pieces of evidence suggest the role of genetic factors in the susceptibility to this multifactorial disease. The present study was performed to determine whether polymorphisms of the surfactant protein SP-A1, SP-A2 and SP-B genes associate with RDS and to evaluate the relative contributions of genetic and environmental factors to the disease etiology. Allelic associations between the candidate genes and RDS were investigated using a matched and unmatched case-control and family-based study design. Disease concordance in monozygotic vs. dizygotic twin pairs was determined to measure the impact of heredity in RDS. SP-A and SP-B genes were shown to play a significant role in susceptibility to RDS. In very premature singleton infants born before 32 weeks of gestation, SP-A1 and SP-A2 allelic variations were associated with RDS, whereas the SP-B gene showed no direct association. Instead, the association between the high-risk (6A2, 1A0) or low-risk (6A3, 1A1/1A2) SP-A alleles and RDS was dependent on SP-B Ile131Thr variation, being restricted to a subset of infants carrying the homozygous genotype Thr/Thr. No allelic associations were evident in premature infants born after 32 weeks of gestation. RDS concordance was not significantly higher in monozygotic than in dizygotic twin pairs, implying a non-genetic disease etiology. However, the present study suggests that the concordance difference underestimates the extent of heredity. Twin pregnancies include intrauterine environmental factors that complicate the interpretation of the hereditary impact. SP-B Ile131Thr variation was associated with RDS in the first-born, but not in the second-born twins. The present results indicate that susceptibility to RDS is highly heterogeneous, involving complex environmental and genetic interactions. The degree of prematurity, singleton vs. multiple pregnancy, and birth order in a multiple birth are environmental confounders that determine disease subgroups. Genetic variations in the SP-A and SP-B genes account for part of the genetic component of RDS.

Nous décrivons dans ce manuscrit la synthèse et l'étude de surfactifs à base de poly(2-méthyl-2-oxazoline) et de corps gras. Pour cela, deux voies de synthèse ont été réalisées. La première qui consiste à amorcer la polymérisation avec un alcool gras tosylé. La deuxième voie de synthèse a été réalisée en amorçant la polymérisation par un alcane iodé. Les surfactifs ainsi obtenus ont une chaîne grasse saturée ayant douze ou dix-huit atomes de carbone et des longueurs de chaînes polymères variables.Ces surfactifs sont examinés afin d'évaluer leur aptitude à la formulation. Ainsi, la valeur de leur concentration micellaire critique a été déterminée par tensiométrie et spectrofluorimétrie. Ensuite, l'évaluation de leurs pouvoirs mouillant et moussant, de leur HLB, de leur température de point de trouble… ont été déterminés afin de les comparer avec leurs homologues POE, les Brij®. Dans l'optique d'une application à la formulation, des tests d'évaluation de leur toxicité ont également été réalisés. Enfin, des préparations cosmétiques ont été formulées, à base de ces surfactifs et des Brij®. Parallèlement, une étude a été menée démontrant l'intérêt du carbonate de glycérol tosylé comme amorceur de la polymérisation de la 2-méthyl-2-oxazoline. Cet amorceur a permis de fonctionnaliser les polyoxazolines en extrémité de chaîne par des fonctions terminales (hydroxy)uréthane. / In this manuscript, we describe the synthesis and the study of surfactants based on poly(2-methyl-2-oxazoline) and vegetable oil derivatives. Two ways for the synthesis are realized. The first path consists to initiate the polymerization with a tosylate fatty alcohol. The second synthetic route was realized by initiating the polymerization by an iodoalkane. The obtained surfactants have au saturated fatty chain with twelve or eighteen carbon atoms and various lengths of polymeric chain. This surfactants are reviewed to assess their suitability for the formulation. Thus, the value of their critical micelle concentration was determined by tensiometry and spectrofluorimetry. After, the evaluation of their wetting and foaming powers, their HLB, their cloud point temperature… was determinded in order to compare with their homologous POE, the Brij®. In the context of an application in the formulation, evaluation tests of toxicity were also made. Next, cosmetic preparations were realized, based on this surfactants and Brij®. In parallel, a study was conducted to demonstrate the tosylate gycerol carbonate interest as initiator in the 2-methyl-2-oxazoline polymerization. This initiator enable to fonctionalize the polyoxazoline in the chain end with (hydroxy)uréthane terminal function.

The ability of surfactants to form micelles and solubilise hydrophobic substances in aqueous environments has been widely exploited in formulation science. In spite of extensive studies over the past few decades by both experimental and theoretical methods, however, it remains difficult to predict key micellar parameters such as their size, shape and nanostructure which is essential for their successful implementation in the solubilisation of active ingredients. This is partly due to the vast number of surfactants commercially available but, in addition, the fragmentation of the field of surfactant science, over recent years, has made it more difficult to identify general trends and properties of surfactant systems. A further challenge is in characterising systems of heavily mixed surfactants since our knowledge on pure surfactant systems may not allow us to predict the behaviour of these systems. The broad aim of this thesis was to contribute to these aspects of surfactant science. The first part of the thesis reports a systematic study of the surfactant structure-micellar structure relationship of pure alkyl ethoxylate (CmEn) surfactants. This was done by independently varying the lengths of the alkyl chain and ethoxylate group and measuring the micellar structural properties. The next part of the thesis reports the effects of solubilisation of two model pesticides, Cyprodinil and Diuron, on the size, shape and internal structure of these surfactant micelles. These pesticides were chosen because they were structurally representative of different features of those widely used in agrochemicals. The final part of the thesis reports the work on binary surfactant mixtures that rationalise the general structural features of mixed micelles and their impact on pesticide solubilisation. Various experimental techniques were used including small angle neutron scattering (SANS), nuclear magnetic resonance (NMR), nuclear Overhauser effect spectroscopy (NOESY NMR), dynamic light scattering (DLS) and UV spectroscopy. The key findings of the thesis were that the micellar core volumes could be predicted with reasonable accuracy using the hydrophilic-lipophilic balance (HLB) of the surfactants in pure micelles. NOESY results revealed protrusions of the terminal methylene groups into the ethoxylate shell, thus providing evidence for the theoretically predicted phenomenon referred to as the-shell interface. SANS revealed that solubilisation of both pesticides caused micellar growth, with the long axial lengths of the micelles growing much longer. These structural changes were associated with the dehydration of the ethoxylate shells. Although a partitioning experiment predicted that the pesticides would be solubilised in the hydrated ethoxylate micellar shell, NOESY measurements revealed that the solubilisation occurred predominantly in the micellar cores. The discrepancy was caused by alkyl chain-ethoxylate mixing leading to the formation of dehydrated palisade regions that entrapped the pesticides towards the cores. The results from the binary mixed micelles showed some signs of synergistic behaviour but no enhancement of pesticide solubilisation.

Orientador: Ines Joekes / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-07T18:47:07Z (GMT). No. of bitstreams: 1 Valentim_IaraBarros_D.pdf: 957586 bytes, checksum: 1311d37d4e3ea52a252e10626fcd04c3 (MD5) Previous issue date: 2006 / Doutorado / Físico-Química / Doutor em Ciências

Das pulmonale Surfactant verbessert durch Herabsetzen der alveolären Oberflächenspannung entscheidend Ventilation und Gasaustausch der Lunge. Die noch nicht ausreichend vorliegende Konzentration des Surfactants bei FG < 35. SSW bedingt u. a. das ANS frühgeborener Kinder. Laut Leitlinie ist bei FG < 27. SSW eine frühe, primäre Surfactantgabe indiziert, bei FG  27. SSW ist die prophylaktische Therapie bei Kindern ohne Lungenreife legitim. In unserer Einrichtung der Neonatologie der Universität Leipzig beschäftigten wir uns mit der Frage, ob nicht auch FG  27. SSW mit erfolgter Lungenreifeinduktion von einer standardisierten Primärgabe von Surfactant im Kreißsaal profitieren und damit typische Spätmorbiditäten dieser FG verhindert werden könnten. Ziel unserer Arbeit war es also, herauszufinden, ob die Ausweitung der bestehenden gestationsaltersabhängigen Grenze FG für eine Primärbehandlung mit Surfactant indiziert ist. Es erfolgte eine retrospektive Auswertung von Kindern eines GA zwischen der 27.–32. SSW, die im Zeitraum vom 01.01.2015 bis zum 31.12.2017 in der Abteilung für Neonatologie der Universitätsklinik Leipzig behandelten wurden. Ausschlusskriterien stellten die Geburt außerhalb der Universitätsklinik Leipzig und die Verlegung nach begonnener Behandlung in eine weitere Klinik dar. In unserer Arbeit untersuchten wir die Unterschiede von Kindern, die entweder primäres Surfactant oder keine prophylaktische Behandlung im Kreißsaal erhalten haben, hinsichtlich der Basisdaten bei Geburt, Verlaufs- und Beatmungsparametern. Mit Hilfe von welchem Verfahren dabei das primäre Surfactant verabreicht wurde, war uns dabei von besonderem Interesse, um eine Empfehlung für einen bevorzugten Applikationmodus, der das spätere Outcome der Kinder positiv beeinflusst, aussprechen zu können. Wir stellten zusammenfassend fest, dass Outcome-Parameter, wie die schwere IVH, das schwere ANS, sowie die endotracheale Beatmungszeit erhöht in der Gruppe der FG auftraten, die primär Surfactant erhielten. Ebenso lag keine signifikante Reduktion durch Primär-Surfactant in der Mortalitäts-, ROP-, BPD- oder NEC/FIP-Rate vor, sondern betraf beide Vergleichsgruppen gleichermaßen (selten). Diese Differenzen relativierten sich allerdings, als Kinder ohne Primärgabe mit Kindern verglichen wurden, die Surfactant mittels des LISA-Verfahren erhielten, was uns darauf schließen lässt, dass eine Primärgabe an Surfactant via LISA keinen Unterschied im Outcome – bis auf PTX und spätere, selektive Surfactantgaben – bewirkt, verglichen mit einer ausbleibenden primären Surfactantapplikation. Wenn also bei FG  27. SSW eine primäre, sowie eine selektive Surfactantgabe ein vergleichbares Outcome erzielt, dann ist eine abwartende, selektive Strategie zu bevorzugen, obwohl somit mit einer erhöhten PTX-Rate, vor allem bei Kindern der 29.–32.SSW, zu rechnen ist, was in der klinischen Routine beachtet werden sollte. Wenn Surfactant prophylaktisch verabreicht wird, dann ist als ungefährlichste Methode mit dem besten Outcome das LISA-Verfahren zu wählen. Unsere Ergebnisse sprechen nicht für eine Ausweitung der Indikation für primäre Surfactantgaben im Kreißsaal. Aufgrund der Divergenz zwischen Schaden und Nutzen dieser Intervention werden allerdings weiterführende prospektive, randomisierte, multizentrische Studien zur Evaluation der gestationsaltersabhängigen Grenze Frühgeborener für eine Primärbehandlung mit Surfactant empfohlen.  :Inhaltsverzeichnis Abkürzungsverzeichnis 1 Einleitung 1.1 Überblick: Frühgeburtlichkeit 1.2 Surfactant 1.2.1 Chemie und Eigenschaften des pulmonalen Surfactants 1.2.2 Historie des Surfactants 1.2.3 Surfactantmangel (ANS) 1.3 Aktuelle Therapieoptionen 2 Zielstellung 3 Patienten und Methoden 3.1 Studienaufbau 3.2 Beobachtungszeitraum, Patientenkollektiv und Auswahl der Parameter 3.3 Datenanalyse und statistische Auswertung 4 Ergebnisse 4.1 Analyse des Gesamtkollektivs (27.–32. SSW) 4.2 Analyse auf Leitlinienkonformität anhand erfolgter Lungenreife und primärer Surfactanttherapie (27.–32. SSW) 4.3 Subgruppenanalyse 27.–32. SSW (mit Lungenreifeinduktion) 4.4 Subgruppenanalyse 27./28. SSW (mit Lungenreifeinduktion) 4.5 Subgruppenanalyse 29.–32. SSW (mit Lungenreifeinduktion) 4.6 Matchpair-Analyse Gesamtgruppe (27.– 32. SSW) 4.7 Matchpair-Analyse 27./28. SSW. 4.8 Matchpair-Analyse 29.–32. SSW 4.9 Zusammenfassung der Ergebnisse 5 Diskussion 6 Zusammenfassung Literaturverzeichnis Anhang Tabellenverzeichnis Abbildungsverzeichnis Selbstständigkeitserklärung

This project consists of two parts. One area of focus in the first part is understanding the interactions between a non-ionic, block copolymer type dispersant and hydrophobically-modified, ethoxylated urethane (HEUR) associative thickeners in water. The dispersant was mixed at various concentrations (0-2% by weight) with HEUR thickeners at 1% by weight concentration in the aqueous medium. This study is an integral part of our attempts to determine mechanisms of viscosity drop when colorant dispersions are added to latex tint base formulations thickened with associative thickeners. One of the HEUR thickeners is a product that has been available for over three decades (HEUR RM-825), whereas the other, HEUR RM-995 is a product recently introduced to minimize the tint base viscosity drop. The old HEUR showed a definitive viscosity maximum as a function of the dispersant concentration. However, the new generation product did not indicate a viscosity maximum within the dispersant concentration range studied; instead it showed a small, but linear increase in viscosity as dispersant level was increased. The next area of focus was on understanding the phase behavior, rheology, and interactions between polymer latex particles and a hydrophobically-modified, ethoxylated urethane (HEUR) associative thickener in water. The influence of the addition of surfactant in some of the systems was also studied. Several types of dispersions were made using two types of polymer latex, two associative thickeners, and two surfactants. Mixtures containing a small particle size acrylic latex and HEUR RM-825 exhibited the most interesting and complex phase behavior and rheology. In experiments wherein the latex particle volume fraction was kept constant, the addition of HEUR caused stable, followed by phase separated (syneresis) and stable mixtures as HEUR concentration was increased. The observed phase behavior is consistent with previous work reported by other investigators. However, detailed rheological data on systems such as these have not been reported, and this report presents the rheological data and correlate rheology with the phase behavior. The stable latex-HEUR mixtures at low HEUR levels show shear-thinning viscosity with well-defined low-shear Newtonian plateaus. As HEUR level is increased wherein syneresis is observed, erratic rheological profiles with shear-thickening are observed. When HEUR level is increased to a region where no syneresis is observed, low shear Newtonian plateaus re-appeared albeit at higher viscosities. The effects of added non-ionic and anionic surfactants on the dispersion are also studied. The main focus of the second part of this project is hybrid organic-inorganic photovoltaics. They have been the focus of recent studies due to their promising use in low-cost, flexible electronics, which can be processed from solution by printing and coating techniques. Understanding the rheology of these nanocomposites is essential in controlling shear flows during printing and application processes. Through rheology, we can determine different properties of poly(3-hexylthiophene) and dodecanethiol (DDT) modified zinc oxide (ZnO-DDT). Semiconductor nanowires such as ZnO have rigid or rod-like macromolecule geometry. Therefore, they have a tendency to have a lytropic liquid crystal (LLC) phase. LLC orders occur spontaneously in solutions with rod-shaped or anistropic objects from isotropic phase to nematic phase above a critical volume fraction which was studied using ZnO-DDT. The shear-induced alignment of the liquid crystal molecules was analyzed, serving as a guide for LLC printing. Furthermore by using this nanocomposite we are able to induced gelation using the ZnO-DDT nanowires in what is considered as a “good solvent,” dichlorobenzene. The kinetics of this gelation process was determined to be of first-order reaction kinetics. Furthermore, a mechanism of this gelation process is also presented.

In this work, copolymers of celulose-g-polystyrene (cel-PS) and celulose-g- poly(methylmetacrylate) (cel-PMMA) were characterized using static and dynamic light scattering, transmission electron microscopy and atomic force microscopy. Preparation of nanoparticles of these hydrophobic copolymers in aqueous solution was further studied, by means of precipitation from dioxane solutions using water with added low-molar-mass surfactants sodium dodecylsulfate (SDS) and dodecyltrimethylammonium bromide (DTMAB). It was shown that the ability of the surfactants to stabilize polymer nanoparticles is driven not only by the hydrophobic effect, but it depends also on specific interactions of the polar group of the surfactant with the surface of the nanoparticles. On the basis of the finding that the efficiency of stabilization of cel-PS copolymers is much higher than in case of linear PS, it can be concluded, that the branched structure of copolymers is favorable for the formation of hydrofobically stabilised polymer-surfactant complexes.