The presence of cholesterol is critical in defining a dynamic lateral structure in pulmonary <p>surfactant membranes, including the segregation of fluid-ordered and fluid-disordered phases. <p>However, an excess of cholesterol has been associated with impaired surface activity both in <p>surfactant models and in surfactant from injured lungs. It has also been reported that surfactant <p>protein SP-C interacts with cholesterol in lipid/protein interfacial films. In the present study, we <p>have analyzed the effect of SP-C on the thermodynamic properties of phospholipid membranes <p>containing cholesterol and on the ability of lipid/protein complexes containing surfactant <p>proteins and cholesterol to form and re-spread interfacial films capable of producing very low <p>surface tensions upon repetitive compression-expansion cycling. We have also analyzed the effect of cholesterol on the <p>structure, orientation and dynamic properties of SP-C embedded in physiologically relevant <p>model membranes. <p><p> / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

Abstract The main objective of this thesis was to research and develop a sensitive characterization method for dielectric powdery substances which could be utilized in various industrial and research fields. With modern electromagnetic simulation tools and the presented experimental measurements, the characterization of dielectric powders using an indirectly coupled open-ended coaxial cavity resonator operating in TEM mode at 4.5 GHz was found to have potential. The modelling and the experimental measurement results of commonly used dielectric powders revealed that, from the nine classical mixing rules, it was possible to derive reliable inclusion permittivity values when using the properties of the perturbed resonator and the Bruggeman symmetric and the Looyenga mixing theories. In addition, the determination accuracy of the inclusion permittivity was found to be greatly improved with the correction factor included into the previously presented permittivity equation of the quarter wave coaxial resonator. Determination of the dielectric losses was found to be reliable when using the differences between the perturbed and unperturbed resonator and the general mixing model equation. The sensitivity of the characterization method was researched with both humidity exposed and surfactant treated modified SiO2, Al2O3 and ZrO2 powders. Experimental results showed that the effect of adsorbed water on the particles was most pronounced when measuring the dielectric losses of the inclusions. Furthermore, a clear correlation with the theory of the general mixing model was found. Thus, in addition to the changed dielectric properties between dry and humidity exposed powders, it was also possible to determine the moisture content with reasonable accuracy. This correlated well with the traditional, mass based, determination. Stearic acid coating of the particles induced only a small change in inclusion permittivity but a notable change in dielectric losses. Unlike the cases with the larger particle sized SiO2 and Al2O3, the dielectric loss of ZrO2 inclusions, with stearic acid coating, was decreased significantly from 6.2 × 10-3 to 3.8 × 10-3. When characterizing magnesium and calcium titanate composite powders, with CaTiO3 molar ratios of 0.0, 0.02, 0.05 and 0.1, the method was found to have good sensitivity and accuracy. Additions of CaTiO3 exhibited a clear increase in net inclusion permittivities from 13.4 up to 14.9 and in dielectric loss tangents from 7.1 × 10-3 up to 8.5 × 10-3. In addition, a good correlation was found in the theoretical determination of the CaTiO3 molar ratios using the resonator measurement results and the general mixing model. The characterization method was proved to be capable of measuring the dielectric properties and detecting even very slight changes in the powders. Thus, the method could be utilized in various types of powdery material characterization, for example, in the analysis and quality control of different composite powders. / Tiivistelmä Väitöstyön päätavoitteena oli tutkia ja kehittää herkkä jauhemaisten eristemateriaalien karakterisointimenetelmä, jota voitaisiin hyödyntää usealla teollisuuden ja tutkimuksen alueella. Hyödyntäen nykyaikaisia sähkömagnetiikan simulointityökaluja sekä kokeellisia mittauksia, havaittiin TEM -moodissa 4,5 GHz taajuudella toimivan avoimen epäsuorasti kytketyn koaksiaalionteloresonaattorin soveltuvan karakterisoimaan eristejauheita. Sähkömagneettinenmallinnus yhdessä yleisesti käytettyjen eristejauheiden kokeellisten mittausten kanssa osoitti, että partikkelin permittiivisyysarvot voitiin johtaa luotettavasti. Tällöin käytettiin näytemateriaalilla täytetyn resonaattorin ominaisuuksia, sekä yhdeksästä vertaillusta klassisesta sekoitusyhtälöstä Bruggeman symmetristä ja Looyengan sekoitusteorioita. Tämän lisäksi tarkkuutta voitiin parantaa huomattavasti lisäämällä korjauskerroin aikaisemmin julkaistuun neljännesaalto-koaksiaaliresonaattorin permittiivisyyden määrittävään yhtälöön. Eristehäviöiden määrittäminen havaittiin luotettavaksi, kun käytettiin mitattavalla materiaalilla muutetun ja tyhjän resonaattorin ominaisuuksien eroja, sekä general mixing model -yhtälöä. Karakterisointimenetelmän herkkyys tutkittiin ilmankosteudelle altistetuilla, sekä pintakäsittelyllä muutetuilla SiO2, Al2O3 ja ZrO2 -jauheilla. Mittaustulokset osoittivat, että partikkelin pinnalle adsorpoituneen veden vaikutus oli kaikkein korostunein, kun mitattiin partikkelien eristehäviöitä. Tämän lisäksi havaittiin myös selkeä korrelaatio general mixing model -teorian kanssa. Näin ollen muuttuneiden eristeominaisuuksien määritysten lisäksi voitiin määrittää jauheen kosteussisältö riittävällä tarkkuudella. Tulokset korreloivat hyvin perinteisen massaeroihin perustuvan määrittämisen kanssa. Partikkelien pinnoitus steariinihapolla aiheutti ainoastaan pienen muutoksen permittiivisyyteen mutta merkittävän muutoksen eristehäviöihin. Toisin kuin suuremman partikkelikoon SiO2:lla ja Al2O3:lla ZrO2 -partikkelin eristehäviö laski huomattavasti steariinihappopinnoituksen jälkeen, 6,2 × 10-3:sta 3,8 × 10-3:een. Karakterisoitaessa magnesium- ja kalsiumtitanaattikomposiittijauheita käyttämällä CaTiO3 -moolisuhteita 0,0, 0,02, 0,05 ja 0,1 menetelmällä havaittiin olevan hyvä herkkyys ja tarkkuus mitattavan materiaalin muutoksille. CaTiO3 -määrän lisäykset aiheuttivat selkeän nousun partikkelien kokonaispermittiivisyyksissä, joka kasvoi 13,4:sta 14,9:ään, sekä häviötangentissa, joka kasvoi 7,1 × 10-3:sta aina 8,5 × 10-3:een. Tämän lisäksi resonaattorin mitattuihin ominaisuuksiin sekä general mixing model -yhtälöön perustuvan teoreettisen määrityksen havaittin korreloivan hyvin CaTiO3 -moolisuhteisiin. Karakterisointimenetelmän osoitettiin soveltuvan eristeominaisuuksien mittaukseen sekä havaitsemaan jopa erittäin pienet muutokset jauheiden eristeominaisuuksissa. Menetelmää voitaisiin hyödyntää usean tyyppisissä jauhemateriaalien ominaisuuksien määrityksissä, kuten esimerkiksi erilaisten komposiittijauheiden analysoinnissa ja laaduntarkkailussa.

Abstract Oily wastewaters are heterogeneous, containing various types of oils, surfactants from detergents, metals etc. Oily wastewaters are produced from a wide range of industries such as metalworking, petroleum refineries, the petrochemical industry, transportation as well as the textile and food industries. Oily wastewaters, especially those containing stable oil-in-water emulsions, require advanced treatment as conventional treatment methods have their limitations to meet ever-stricter environmental regulations. Ultrafiltration is a widely accepted and commonly used treatment method for oily wastewaters. The first aim of this thesis was to increase knowledge concerning the performance of an industrial-scaled ultrafiltration-based process treating concentrated real oily wastewaters. The demand for a more effective pre-treatment method for ultrafiltration to enhance performance and decrease fouling of membrane was observed. The second aim of the thesis was to investigate the suitability and efficiency of different methods for treating concentrated model oil-in-water emulsions and real oily wastewaters. The treatment methods studied were electrocoagulation (electrolytic dissolution of anodic metal), conventional coagulation-flocculation followed by either sedimentation or dissolved air flotation, and dissolved air flotation utilising cationic air bubbles. Electrocoagulation was discovered to be a promising treatment method for various types of oil-in-water emulsions. Dissolved air flotation with cationic modified air bubbles was proven to be an efficient method with even higher treatment results with smaller chemical doses when compared to conventional coagulation-flocculation followed by dissolved air flotation. The biodegradation of various components is an important measure of their impact on the environment in case of spillage. The third aim of the thesis was to explore the biodegradability of different types of oils and surfactants in solution conditions and soils. It was discovered that the biodegradation of light fuel oil continued during a three-month time period, reaching a biodegradation degree of over 60% in mineral-rich soil. For surfactants, their distinct effect on the biodegradation of organic material in soil was observed, and it masked the biodegradation of the surfactants themselves. / Tiivistelmä Öljyiset jätevedet ovat heterogeenisiä, sisältäen mm. erityyppisiä öljyjä, metalleja ja pesuaineiden pinta-aktiivisia aineita. Öljyisiä jätevesiä muodostuu laajalti eri teollisuuksista, kuten metallintyöstöstä, öljyn jalostuksesta, petrokemian teollisuudesta, ruoka- ja tekstiiliteollisuudesta sekä liikenteestä. Öljyiset jätevedet, varsinkin stabiileja öljyemulsioita sisältävät, vaativat tehokkaan käsittelymenetelmän, jotta ympäristölainsäädännön ja luvituksen ehdot täyttyvät. Ultrasuodatus on yleisesti käytössä oleva öljyisten jätevesien käsittelymenetelmä. Tämän väitöstyön ensimmäinen tavoite oli lisätä tietoutta teollisen mittakaavan konsentroituneiden öljyisten jätevesien ultrasuodatusprosessien tehokkuudesta. Prosessien strategisista kohdista kerättyjen öljyisten jätevesien karakterisointitulosten perusteella havaittiin, että ennen ultrasuodatusta tarvitaan tehokas esikäsittelyvaihe prosessin tehostamiseksi ja ultrasuodattimen tukkeutumisen vähentämiseksi. Täten toinen väitöstyön tavoite oli selvittää eri menetelmien soveltuvuutta ja tehokkuutta konsentroituneiden malliaineina käytettyjen öljyemulsioiden ja öljyisten jätevesien käsittelyssä. Tutkitut käsittelymenetelmät olivat elektrokoagulaatio (sähkökemiallinen flokkaavien metalli-ionien liuottaminen anodilta), koagulaatio-flokkulaatio ja laskeutus/korkeapaineflotaatio sekä korkeapaineflotaatiomenetelmä, joka hyödyntää kationisia ilmakuplia. Elektrokoagulaation todettiin olevan erittäin tehokas käsittelymenetelmä, jolla saavutettiin korkeat puhdistustulokset erityyppisille öljyemulsioille. Korkeapaineflotaatiolla, joka hyödyntää kationisia ilmakuplia, saavutettiin hyvät puhdistustulokset jopa pienemmillä kemikaalimäärillä verrattuna perinteiseen koagulaatio-flokkulaatioon ja korkepaineflotaation. Erilaisten komponenttien biohajoavuus on tärkeä suure arvioitaessa niiden ympäristövaikutuksia. Väitöstyön kolmas tavoite oli selvittää erilaisten öljyjen ja pinta-aktiivisten aineiden biohajoavuutta erilaisissa liuosolosuhteissa ja maa-aineksissa. Tärkeimmät biohajoavuustutkimustulokset olivat, että kevyt polttoöljy saavutti kolmen kuukauden mittauksen aikana yli 60 % biohajoavuusasteen mineraalirikkaassa maa-aineksessa. Pinta-aktiivisten aineiden havaittiin lisäävän huomattavasti maan orgaanisen aineksen biohajoamista, ja tämä vaikeutti itse pinta-aktiivisten aineiden biohajoamisen arviointia.

Abstract Pulmonary surfactant is a lipid-protein mixture that lines the inner surface of the lung. The main function of surfactant is to reduce surface tension at the air-liquid interface, thus preventing alveolar collapse at the end of expiration. Lack of surfactant is the main cause of respiratory distress syndrome (RDS) in preterm infants. Very preterm babies are at risk of developing a lung disease called bronchopulmonary dysplasia (BPD). The surfactant proteins SP-A, -B, -C and -D have important functions in surfactant structure, homeostasis and innate immunity of the lung. The genes of these proteins have been studied as candidates for several multifactorial lung diseases both in adults and in children. The aim of the present study was to examine the genetic variation in SP genes and to evaluate the role of SP gene polymorphism in the etiology of severe pulmonary infantile diseases, including RDS, BPD and severe respiratory syncytial virus (RSV) infection among the Finnish population. Conventional allelic association methods in combination with multiparameter analysis and family-based transmission disequilibrium test (TDT) were used. The SP-D Met11 allele was associated with a risk for severe RSV bronchiolitis in a matched case-control setting of 84 infants with severe RSV infection and 93 control infants. The variants of the SP-C gene had no detectable association with BPD. However, a modest association of SP-C Asn138 and Asn186 alleles with RDS was found. A length variation in the SP-B gene was associated with BPD among very preterm infants born before 32 weeks of gestation. The SP-B intron 4 deletion variant allele increased the risk for BPD especially in very low birth weight infants. The association was confounded by birth order, being evident only among presenting infants, who are more prone to ascending infections during a preterm birth process. The present study provides new evidence about the significance of SP gene polymorphisms in the etiology of complex infantile pulmonary diseases, including RDS, BPD and severe RSV bronchiolitis. The results help us to understand the molecular mechanisms underlying these diseases and may, in the long run, enable better treatment of these life-threatening diseases. / Tiivistelmä Keuhkosurfaktantti on keuhkon sisäpintaa peittävä kalvomainen rasva-proteiinikompleksi, jonka tärkein ominaisuus on pintajännityksen vähentäminen keuhkorakkuloissa. Surfaktantin puutos ennenaikaisesti syntyneillä lapsilla aiheuttaa hengitysvaikeusoireyhtymän, RDS-taudin (respiratory distress syndrome). Alle 30 raskausviikon iässä syntyneistä, useimmiten RDS-taudin saaneista keskosista n. 30 % sairastuu vakavaan krooniseen keuhkotautiin, BPD-tautiin (bronchopulmonary dysplasia). Surfaktanttiproteiineilla SP-A, -B, -C ja -D on osoitettu olevan tärkeä tehtävä surfaktantin toiminnassa ja keuhkon synnynnäisessä immuniteetissa. Tämän tutkimuksen tavoitteena oli selvittää surfaktanttiproteiineissa esiintyvän geneettisen muuntelun määrää ja merkitystä keskosten RDS- ja BPD-taudeissa sekä pienten lasten vakavassa respiratory syncytial -viruksen (RSV) aiheuttamassa keuhkotulehduksessa. Tutkimuksen laajin osa keskittyi tutkimaan keskosten BPD-tautia ja surfaktanttiproteiinien geenien osuutta siinä. Geneettisen muuntelun merkitystä tarkasteltiin populaatiogeneettisin keinoin tapaus-verrokkiasetelmissa ja perheaineistojen avulla. Yhteensä analysoitiin noin tuhannen lapsen ja yli kahdensadan vanhemman DNA-näytteet. Tutkimuksessa havaittiin SP-D-geenissä olevan metioniini11-geenimuodon liittyvän pienten lasten vakavaan RSV-infektioon. Lisäksi saatiin uutta tietoa SP-C-geenin populaatiotason yleisestä muuntelusta ja todettiin SP-C:n asparagiini138 ja asparagiini186 -geenimuotojen yhteys keskosten RDS-taudin esiintymiseen. Merkittävin löydös oli SP-B-geenissä olevan deleetiovariantin kytkeytyminen alle 32-viikkoisina syntyneiden keskosten BPD-tautiin. Geneettisen altistuksen lisäksi BPD-tautiin sairastumiseen vaikuttivat lukuisat keskosuudelle ominaiset seikat, kuten alhainen syntymäpaino, RDS-tauti ja syntymähetkellä todettu hapenpuute. Geneettisen tekijän vaikutus oli voimakkain erittäin pienipainoisilla keskosilla. Tutkimuksen tulokset ovat tuoneet arvokasta lisätietoa surfaktanttiproteiinien geenien osuudesta keskosten RDS- ja BPD-taudeissa sekä pienten lasten vakavassa RSV-infektiossa. Ne auttavat ymmärtämään näiden molekyylibiologisia syntymekanismeja ja voivat ajan mittaan olla edistämässä uusien hoitomuotojen kehittämistä.

La contamination des sols et sédiments par les polychlorobiphényls (PCB) pose un problème sanitaire et environnemental à l’échelle mondiale, en raison de la récalcitrance et de la toxicité de ces composés. L’objectif de cette thèse est de chercher un procédé de remédiation de sédiments contaminés aux PCB en utilisant le fer zérovalent (Fe0). D’abord, une campagne de prélèvement a été menée sur des sites contaminés par le recyclage des déchets électroniques en Chine du sud. La contamination en PCB n’était pas aussi forte que prévue, mais la présence de métaux lourds accentue la difficulté de la remédiation. Ensuite, a été étudiée la déchloration des PCB par le Fe0 en solution aqueuse, en présence de métaux et surfactants. Les résultats ont montré la déchloration progressive des PCB et révélé l’itinéraire réactionnel avec la spécificité des congénères et la régio-spécificité. L’importance relative des facteurs qui influent se classe selon : tensioactif > acide humique > pH > Ni2. La décontamination du sédiment a été étudiée par 1) lavage avec une solution aqueuse de tensioactif suivie de la déchloration des PCB en solution et 2) mélange direct avec le Fe0 et les tensioactifs. La seconde approche s’est avérée prometteuse pour la remédiation / Soil and sediment contamination by polychlorinated biphenyls (PCBs) is a global health and environmental concern, since PCBs are toxic and recalcitrant. The aim of this thesis is to find a remediation process to PCBs contaminated sediments by using zerovalent iron (ZVI). To begin the studies on remediation, a survey was conducted on sites contaminated by e-waste recycling activities in south China. PCBs contamination was not as severe as previously, whereas the co-existence of PCBs and heavy metals increases the difficulty of remediation. Afterwards, the feasibility PCBs degradation by ZVI in aqueous solutions was investigated. Results confirmed the stepwise dechlorination of PCBs by ZVI and the major pathway with congener specifity and regiospecifity. The relative importance of the influential factors to ZVI degradation of PCBs was in the order of surfactants > humic acid > pH > Ni2+. Sediment decontamination was studied by 1) washing with an aqueous solution of surfactant followed by ZVI dechlorination of PCBs and 2) direct mixing with ZVI and surfactant solution. The second approach gave promising results for remediation

De nos jours, la préservation de l’environnement est un enjeu majeur. Avant cette prise de conscience, de nombreux polluants ont été rejetés dans la nature. Parmi eux, les hydrocarbures sont très souvent rencontrés. Or, ils sont reconnus pour leur toxicité et leur persistance accrue. La mise en place de méthodes efficaces de dépollution est donc primordiale. Les méthodes classiques nécessitent l’excavation ou le pompage des zones contaminées, imposant un coût de dépollution élevé. C’est pourquoi des techniques de dépollution in-situ ont été développées afin de réduire ces coûts, tout en garantissant des rendements de dépollution efficaces. Les travaux menés durant cette Thèse ont permis de déterminer, pour plusieurs techniques de traitement, les facteurs limitants inhérents à la technique, mais aussi de quantifier le rôle du contact entre agents de traitement et zone polluée ou des effets densitaires. Les techniques in-situ utilisées sont : l’oxydation chimique in situ, le lavage par tensio-actifs, l’injection d’air (sparging) et le traitement thermique. Trois niveaux d’expérience ont été étudiés : le batch, la colonne et le pilote 3D. Les réacteurs fermés, ont permis la comparaison des oxydants en statiques face à une matrice plus ou moins riche en matières organiques. Les colonnes ont mis en avant l’influence du mode d'injection appliqué vis-à-vis des propriétés physico-chimiques des polluants (cinétique réactionnelle, pression de vapeur, température d’ébullition, etc.). Les pilotes 3D, d’un volume d’un 1 m3, ont permis de comparer les différentes techniques sur un milieu hétérogène présentant des zones peu perméables, difficiles à traiter. A partir des résultats acquis et de modélisation numérique des expériences, il est dorénavant possible de mieux ajuster la méthode de traitement et surtout de comparer différentes méthodes pour un contexte hydrogéologique donné. / Pollution of soils and aquifers by Diesel fuel compounds is a widespread remediation issue. Problems due to soil remediation are more and more difficult to treat. Hydrocarbons are often encountered. But they are known for their toxicity and increased persistence. The establishment of effective remediation methods is paramount. Conventional methods require excavation or pumping contaminated areas requiring a high abatement costs. That is why, in-situ remediation techniques have been developed to reduce these costs while ensuring efficient pollution control returns. The work done during this thesis has determined for several treatments, the limiting factors inherent the treatment, but also quantifies the role of contact between agents and pollutants or density effects. In-situ treatments are: in situ chemical oxidation, surfactants flushing, air sparging and thermic treatment. Three levels of experience were investigated: batch, column and 3D Pilot. Batchs, enabled the comparison of oxidants in sand and natural soil. The columns have highlighted the influence of the injection method applied occurs toward the physical and chemical properties of contaminants (reaction kinetics, vapor pressure, boiling temperature, etc.). 3D Pilot, have a volume of 1m3. They were used to compare the different treatments on a heterogeneous medium having low permeability zones, difficult to treat. From the results of numerical modeling and experiences, it is possible to adjust the treatment method and especially to compare different methods for a given hydrogeological context.

The thesis presents work regarding amphiphilic molecules associated in aqueous solution or at the liquid/solid interface. Two main topics are included: the temperature-dependent behavior of micelles and the adsorption of dispersants on carbon nanotube (CNT) surfaces. Various NMR methods were used to analyze those systems, such as chemical shift detection, spectral intensity measurements, spin relaxation and, in particular, self-diffusion experiments. Besides this, small angle X-ray scattering (SAXS) was also applied for structural characterization.   A particular form of phase transition, core freezing, was detected as a function of temperature in micelles composed by a single sort of Brij-type surfactants. In mixed micelles, that phase transition still occurs accompanied by a reversible segregation of different surfactants into distinct aggregates. Adding a hydrophobic solubilizate shifts the core freezing point to a lower temperature. Upon lowering the temperature to the core freezing point, the solubilizate is released. The temperature course of the release curves with different initial solubilizate loadings is rationalized in terms of a temperature-dependent loading capacity.   The behavior of amphiphilic dispersant molecules in aqueous dispersions of carbon nanotubes (CNTs) has been investigated with a Pluronic-type block copolymer as frequent model dispersant. Detailed dispersion curves were recorded and the distribution of the dispersant among different available environments was analyzed. The amount of dispersed CNT was shown to be defined by a complex interplay of several factors during the dispersion process such as dispersant concentration, sonication time, centrifugation and CNT loading. In the dispersion process, high amphiphilic concentration is required because the pristine CNT surfaces made available by sonication must be rapidly covered by dispersants to avoid their re-attachment. In the prepared dispersions, the competitive adsorption of possible dispersants was investigated that provided information about the relative strength of the interaction of those with the nanotube surfaces. Anionic surfactants were found to have a strong tendency to replace Pluronics, which indicates a strong binding of those surfactants.   CNTs were dispersed in an epoxy resin to prepare nanotube-polymer composites. The molecular mobility of epoxy was investigated and the results demonstrated the presence of loosely associated CNT aggregates within which the molecular transport of epoxy is slow because of strong attractive intermolecular interactions between epoxy and the CNT surface. The rheological behavior is dominated by aggregate-aggregate jamming. / <p>QC 20180103</p>

Les lubrifiants à base aqueuse sont très largement utilisés dans les procédés de mise en forme des métaux comme le tréfilage, car ils combinent d’excellentes capacités calorifiques à de bonnes propriétés tribologiques. Pour répondre à des exigences d’augmentation de la productivité, la compréhension des mécanismes de lubrification est nécessaire. L’objectif de ces travaux est d’établir le lien entre l’organisation des molécules en solution dans le lubrifiant et son pouvoir lubrifiant. La démarche expérimentale consiste à déterminer les propriétés structurales et tribologiques d’un système modèle aqueux, composé d’acides gras et d’éthylène diamine, principaux ingrédients des lubrifiants. Le diagramme de phases du système modèle est établi en s’appuyant sur des techniques de microscopie optique de polarisation, diffusion des rayons X aux petits angles (DXPA) et cryofracture. Pour un rapport molaire entre la diamine et les acides gras supérieur à 1, une succession de phases lamellaire, hexagonale et micellaires, biréfringente sous écoulement et isotrope, est observée avec la dilution. Une attention particulière est accordée à la phase lamellaire qui présente des défauts à l’approche de la transition vers la phase hexagonale. Les analyses réalisées en DXPA, cryofracture et RMN relient leur existence à une modulation de l’épaisseur de la bicouche et une augmentation de la courbure liées au couplage entre les acides gras et les contre-ions amines. Les propriétés lubrifiantes de l’ensemble de ces phases sont également comparées à l’aide d’un tribomètre qui réalise un contact entre un disque et une bille sous une cinématique de contact contrôlée, en régime de lubrification élastohydrodynamique. En plus des mesures de frottement, l’observation simultanée du contact permet de suivre la formation du film lubrifiant entre les surfaces et son évolution. L’influence de l’organisation supramoléculaire du lubrifiant sur son comportement est mise en évidence : les échantillons présentant une organisation lamellaire fournissent les meilleurs résultats en termes de réduction du frottement. L’organisation en bicouches de la phase lamellaire au sein du contact et ses propriétés piézovisqueuses peuvent expliquer sa portance accrue et sa prédisposition naturelle à la réduction du frottement. / Water based lubricants are widely used in metal forming processes due to their good cooling and lubrication capabilities. The understanding of the lubrication mechanisms is necessary to improve the current lubricant efficiency. The goal of this work is to correlate the structural properties of the lubricant to its lubricating behaviour. As mixtures of ethylene diamine and fatty acids in water are some of the main ingredients of such lubricants, their phase behaviour and tribological properties are investigated for different compositions. The phase diagram of the model system is established by using optical microscopy of polarisation, small angle X-rays scattering (SAXS) and freeze-fracture transmission electron microscopy (FF-TEM). For a molar ratio between diamine and fatty acids upper to 1, a succession of lamellar, hexagonal and micellar phases is observed with the dilution. A particular attention is turned to the lamellar phase which presents defects close the transition towards the hexagonal phase. According to SAXS, nuclear magnetic resonance and FF-TEM analyses, we propose that their existence is due to a modulation of the bilayer thickness and an increase of the curvature resulted from the evolution of the coupling between the fatty acids polar heads and the amine counter-ions. The lubricating ability of these phases is then investigated experimentally using an EHL tribometre that simultaneously enables contact visualisation, film thickness and friction measurements in controlled kinematic conditions. The influence of the lubricant structure on its tribological behaviour is revealing: the lowest friction coefficients are obtained with lamellar samples. The organisation in bilayers of the lamellar phase within the contact and its piezoviscous properties can explain its greater load-bearing capacity and its natural predisposition to the reduction of the friction.

A busca por tecnologias cada vez mais eficazes no tratamento de águas e efluentes fez com que o desenvolvimento de membranas desempenhasse um papel importante nos processos de separação. A nanofiltração apresenta-se como uma tecnologia promissora para remoção de sais multivalentes em soluções aquosas. O preparo de membranas poliméricas pela técnica de inversão de fases permite a obtenção de estruturas distintas. Neste estudo avaliou-se o uso de diferentes não-solventes no preparo de membranas de poli(fluoreto de vinilideno) pelo método de inversão de fases, quanto às características estruturais e propriedades funcionais. Foram utilizados como não-solventes: água destilada, solução de dodecil sulfato de sódio e etanol/água, resultando nas membranas denominadas MT1, MT2 e MT3, respectivamente. O uso de um surfactante aniônico, como o dodecil sulfato de sódio, no preparo de membranas de poli(fluoreto de vinilideno) apresenta-se como uma inovação tecnológica. O uso de diferentes não-solventes alterou a taxa de precipitação do polímero, o que ocasionou alterações na estrutura química, morfológica, cristalina e nas propriedades de transporte das membranas. Análises de microscopia eletrônica de varredura e porosimetria de deslocamento líquido-líquido mostraram a obtenção de estruturas assimétricas, com poros na ordem de 1-2 nm para as membranas MT1 e MT2, e estrutura simétrica, com alta porosidade, para a membrana MT3. A análise de espectroscopia de infravermelho com transformada de Fourier mostrou a presença das fases cristalina α e β nas três membranas e no polímero. Análise termogravimétrica realizada em atmosfera inerte apresentou massa residual em torno de 20-30 % referente ao material carbonáceo, o qual foi eliminado com a utilização de atmosfera oxidante na análise. Os valores de cristalinidade aparente, do polímero e das membranas, apresentaram grandes variações quando determinados pela técnica de calorimetria exploratória diferencial, porém quando determinados a partir dos difratogramas obtidos pela técnica de difração de raios X, a variação foi pequena, apresentando valores em torno de 47%. A avaliação da composição química da superfície das membranas, por espectroscopia de fotoelétrons induzidos por raio X, mostrou que houve variação na quantidade de ligações C-F quando diferentes não-solventes foram utilizados. Essas variações contribuíram para alterações na hidrofobicidade das membranas. As membranas MT1 e MT2 apresentaram características hidrofílicas, com ângulo de contato em torno de 70°, e a membrana MT3 apresentou característica hidrofóbica, com ângulo de contato em torno de 142°. A maior hidrofobicidade da membrana MT3 é resultante da rugosidade superficial e da maior composição relativa de ligações C-F na superfície desta membrana. Ensaios de permeação realizados até a pressão de 20 bar mostraram que a membrana MT2 sofreu maior efeito de compactação e apresentou menor fluxo de permeado. Os ensaios realizados com soluções de cloreto de sódio, de cálcio e férrico mostraram diferentes eficiências de retenção. Para as membranas MT1 e MT2 a retenção de sais mono e divalentes foi praticamente igual, em torno de 5%. Para a solução de cloreto férrico, a retenção apresentou valores médios em torno de 16% e 27% para as membranas MT1 e MT2, respectivamente. Em função do tamanho de poros apresentados e da pressão transmembrana aplicada nos ensaios de permeação, as membranas MT1 e MT2 podem ser utilizadas em processos de nanofiltração. / The search for increasingly efficient technologies in water and effluent treatment made the development of membranes take on an important role in separation processes. The nanofiltration is presented as a promising technology for removal of multivalent salt in aqueous solution. The polymeric membranes preparation by phase inversion technique allows the obtaining of different structures. This study evaluated the use of different nonsolvents in the poly(vinylidene fluoride) membrane preparation, by phase inversion method, on the structural characteristics and functional properties. Were used as nonsolvents: distilled water, solution of sodium dodecyl sulfate and ethanol/water, resulting in the membranes called MT1, MT2 and MT3, respectively. Use of an anionic surfactant, like as sodium dodecyl sulfate, in the preparation of poly(vinylidene fluoride) membranes is presented as a technological innovation. The use of different non-solvents changed the rate of polymer precipitation which caused changes in chemical, morphology and crystalline structures, and transport properties of the membranes. Scanning electron microscopy and liquid-liquid displacement porosimetry analysis showed asymmetric structures, with pores on the order of 1-2 nm for the MT1 and MT2 membrane, and symmetrical structure, with a high porosity for MT3 membrane. The analysis by Fourier transform infrared spectroscopy showed the presence of α and β crystalline phases in the three membranes and in the polymer. Thermogravimetric analysis carried out in an inert atmosphere showed residual mass around 20-30% from the carbonaceous material, which was eliminated with the use of an oxidizing atmosphere in the analysis. The values of apparent crystallinity of the polymer and the membranes showed large variations, by differential scanning calorimetry technique, but when determined from the diffractograms obtained by X-ray diffraction technique, the variation was small, showed values around 47%. The evaluates of the membranes chemical surface composition by X-ray photoelectron spectroscopy showed that there was variation in the amount of C-F bonds, where different non-solvents were used. These variations contributed to changes in membranes hydrophobicity. The MT1 and MT2 membranes showed hydrophilic characteristics with contact angle around 70°, and the MT3 membrane showed hydrophobicity characteristics with contact angle around 142°. The highest hydrofobicity of the MT3 membrane is result of the surface roughness and the relative composition of CF bonds on this membrane surface. Permeation tests performed until a pressure of 20 bar, it was found that the MT2 membrane has a greater effect compression and showed a lower permeate flux. Tests conducted with solutions of sodium, calcium and ferric chloride showed different retention efficiencies. For MT1 and MT2 membranes the retention of mono and divalent salts was practically equal, around 5%. For the solution of ferric chloride, the retention showed medium values around 16% and 27% for the MT1 and MT2 membranes, respectively. Due to the pore size presented and transmembrane pressure applied on permeation tests, the MT1 and MT2 membranes may be used in nanofiltration processes.

This thesis deals with the study of preparation and characterization of hyaluronan-micelle aggregates. The theoretical part deals with drug delivery systems, characterization of used materials and methods especially fluorescence spectroscopy, dynamic light scattering and turbidimetry. Methods of determination of measured data are summarized in the experimental section. The result section is divided into two subsections dedicated to different preparation methods of hyaluronan-surfactant complexes. Induced aggregates of hyaluronan with Septonex are characterized in terms of their origin and stability, and the results are compared with previously studied surfactants CTAB. In the second part are discussed so-called decorated micelles, their formation, properties and stability.