Les PolyGlycosides d'Alkyle (APGs) sont des agro-tensioactifs dont les propriétés de surface, la biodégradabilité et l'innocuité vis-à-vis de la peau leur offrent de nombreuses applications dans les domaines de la détergence, de la cosmétique et de l'alimentaire. Les APGs sont synthétisés selon la réaction de glycosidation acido-catalysée de Fischer entre un sucre et un accepteur de glycosyle, tel qu'un alcool gras. A l'échelle industrielle, cette voie de synthèse présente plusieurs contraintes liées à la faible solubilité du sucre dans l'alcool lipophile, l'utilisation de pressions réduites et la manutention de catalyseurs acides toxiques et/ou corrosifs. Ces facteurs imposent un équipement spécifique, augmentent les coûts de production et favorisent la dégradation des APGs. Dans un premier temps, les sulfoxydes et les sulfones ont été utilisés comme solvants dans la synthèse d'APGs sans catalyseur et à pression atmosphérique. Cette méthodologie est transposable à de nombreux donneurs et accepteurs de glycosyle. Notre étude a montré que la réaction de glycosidation est catalysée par les acides organiques produits par caramélisation partielle du sucre. La faible solubilité des solvants soufrés dans les alcools gras à température ambiante a été mise à profit dans la mise au point d'un procédé de synthèse d'APGs permettant la récupération et le recyclage de ces solvants. Un milieu réactionnel biphasique décanol - sulfolane a été décrit pour l'obtention d'un rendement en xylosides de décyle supérieur à 80 % en un temps de réaction remarquablement court. La synthèse d'APGs par conversion directe de la biomasse lignocellulosique a fait l'objet de la seconde partie de ce travail. La réaction de transglycosidation du xylane et des hémicelluloses de peuplier a été réalisée sous activation thermique, sans solvant ou en présence de diméthylsulfoxyde, et sous irradiations micro-ondes. L'efficacité de chaque mode d'activation à promouvoir la réaction de transglycosidation a été discutée en fonction de l'origine botanique et de la composition chimique des matières végétales. / Alkyl PolyGlycosides (APGs) are biobased and biodegradable amphiphilics with good surfactant properties and low skin irritability, which are sought in cosmetics, detergents and food. APGs are synthesized by acid-catalyzed Fischer's glycosidation of a carbohydrate source and a glycosyl acceptor such as a long-tailed alcohol. Industrial APGs production suffers from various drawbacks such as the poor solubility of the carbohydrate in the fatty alcohol, the pressure management and the use of toxic or corrosive acid catalysts. Those issues impose more stringent demand on equipment, increase the production costs and favor APGs degradation reactions.Firstly we have been involved in developing an innovative strategy for the catalyst-free synthesis of APGs under atmospheric pressure. Sulfoxides and sulfones have been efficiently used for the manufacture of APGs starting from various glycosyl donors and acceptors. The reaction was induced by organic acids produced by partial carbohydrate caramelisation. Interestingly some of the sulfur-containing solvents were not soluble in fatty alcohols at room temperature whereas the reaction medium was homogenous at the glycosidation temperature. These solvents have been easily recovered and recycled without decrease of APGs yields. A decanol-sulfolane biphasic reaction medium has been designed for the production of decyl-D-xylosides in short reaction times and yields up to 83 %.The second phase of this work was focused on the direct conversion of lignocellulosic materials into APGs. The transglycosidation reaction of xylan and poplar hemicelluloses has been studied under thermal activation, without solvent or in the presence of dimethylsulfoxide, and under microwave irradiations. The efficiency of each activation mode has been discussed as a function of the botanical origin and the chemical composition of lignocellulosic substrates.

Marangoni flows are free-surface flows driven by gradients of surface tension. Because surface tension depends on chemical composition, Marangoni flows may be generated by the uneven distribution of surface-active species at an interface. The primary goal of this thesis is to develop a rigorous computational framework for the simulation of the fluid dynamical and interfacial phenomena underlying the physics of Marangoni flows. The focus is on characterizing the different dynamical regimes generated by the presence of surface-active species (surfactants) at an interface. The computational framework was developed using direct numerical simulation, that is, by simultaneously solving the full system of partial differential equations governing the free-surface flow and the surfactant transport on a continually deforming interface. Results from the simulations enabled detailed examination of the interfacial mechanisms of surfactant transport and provided a comprehensive picture of the free-surface flow. Analysis of the results established limits of applicability of scaling solutions previously proposed in the literature, calculated the necessary corrections, and also lead to the discovery of previously unobserved scaling laws in viscous Marangoni flows. New findings from this research not only enhance the fundamental understanding of the physics of Marangoni flows, but also the ability to accurately predict the behaviour of Marangoni flows and the associated transport of surface-active species, which is critical to the understanding of important natural and biomedical processes, ranging from the surfactant-driven propulsion of insects and microorganisms to the spreading of drugs and natural surfactants (proteins) in the eye and lungs. Controlled Marangoni transport of chemical species is also relevant to a wide range of environmental and technological processes, with applications ranging from cleaning of oil spills to coating of microfluidic devices.

This thesis is focused on mixed systems of various copolymers (double hydrophilic block and gradient polyelectrolytes, hydrophobic graft copolymers) and low-molar-mass compounds (sodium dodecyl sulfate as a representative of a ionic surfactant or superparamagnetic iron oxides in the form of nanocrystals). The electrostatic and hydrophobic interactions in the studied systems in aqueous solutions leading to aggregation behavior and to the formation of co-assembled nanoparticles were investigated by combination of scattering and microscopy techniques, including light, X-ray and neutron scattering, electron microscopy and atomic force microscopy. Powered by TCPDF (www.tcpdf.org)

L’objectif de ce travail de thèse est de développer de nouveaux agents tensioactifs, capables de s’auto-assembler sous forme de micelles permettant de solubiliser les principes actifs insolubles, en vue de leur administration par voie intraveineuse. Cette étude a permis la synthèse, la caractérisation physico-chimique ainsi que l’évaluation toxicologique in vitro et in vivo de nouveaux agents tensioactifs d’origine naturelle. Au cours de cette étude, différentes familles de tensioactifs ont été évaluées. Ces nouveaux agents tensioactifs sont composés d’une partie hydrophobe de type cholestérol, sels biliaires ou lipides, associée via une fonction amide à une partie hydrophile dérivée d’acides aminés tels que la lysine, la glutamine ou l’acide glutamique.Ces travaux expérimentaux ont permis d’étudier l’influence de la flexibilité de la partie hydrophobe sur la capacité de solubilisation des tensioactifs. Cette étude a montré que l’efficacité de solubilisation est reliée à la flexibilité de la partie hydrophobe. L’utilisation d’agents tensioactifs composés d’une chaîne lipidique saturée flexible a permis de solubiliser efficacement le principe actif insoluble avec un taux de charge de 46 % (m/m). Les tensioactifs composés de lipides saturés sont donc plus efficaces en termes de solubilisation que les dérivés de stéroïdes ou de lipides polyinsaturés, moins flexibles. Les études de toxicité ont mis en évidence la relation ente la structure chimique des tensioactifs et leur toxicité, en particulier vis-à-vis des membranes cellulaires. L’introduction de doubles liaisons en configuration cis dans la partie lipidique des tensioactifs permet de diminuer leur interaction avec les membranes cellulaires et donc leur toxicité mais diminue également leur capacité de solubilisation. Le développement de nouveaux agents tensioactifs nécessite donc de trouver un compromis entre la capacité de solubilisation et la toxicité des tensioactifs. / The aim of this thesis was to develop novel surfactants, able to self-assemble into micelles and to solubilize insoluble drugs intented for intravenous injection. Natural-based surfactants were synthesized and their physico-chemical properties were evaluated. In addition, their in vitro and in vivo toxicity were evaluated. Their drug solubilization abitity was also investigated. Three surfactant classes were evaluated. They were composed of a hydrophobic moiety, such as cholesterol, bile salts or lipids, bonded to a hydrophilic moiety, deriving from amino acids, such as lysine, glutamine or glutamic acid, via an amide bond.The influence of surfactant hydrophobic moiety flexibility on drug solubilization ability was evaluated. This study evidenced that solubilization efficiency is related to the surfactant hydrophobic moiety flexibility. The use of surfactants with flexible and saturated lipidic moieties increased drug water solubility with a drug loading of 46 % (w/w). Saturated lipid-based surfactants exhibited a better solubilization efficiency, in comparison with steroid-based surfactants or poly-unsaturated-based surfactants. Toxicity studies evidenced the relation between surfactant chemical structure and their toxicity, in particular with cell membranes. The introduction of double bond in cis configuration in surfactant lipidic moiety decreased their interaction with cell membranes and thus their toxicity. In addition, this chemical modification also decreased their solubilization ability. To develop novel surfactants, it is thus necessary to take into account drug solubilization ability and toxicity of surfactants.

Ayant une partie hydrophile et une partie hydrophobe, les tensioactifs peuvent s'adsorber sur des interfaces et d'abaisser la tension interfaciale (γ), ce qui améliore les propriétés interfaciales. Tensioactifs chargés sont également utilisés dans des applications biologiques, par exemple dans la livraison de gènes. Dans cette thèse, nous avons étudié les propriétés d'adsorption des tensioactifs, à la fois aux interfaces air/eau et sur l'ADN pour former des complexes.La première partie de la thèse se concentre sur les études d'interface de tensioactifs. Pour comprendre comment ils fonctionnent dans ces applications, il est important de connaître les échelles de temps de l'adsorption et la désorption de surfactant. Ainsi, il est nécessaire d'étudier l'adsorption et la cinétique de désorption, qui sont déjà largement étudié. Cependant, les études traditionnelles ont tendance à faire de nombreuses hypothèses, par exemple, l'extension de l'applicabilité des relations d'équilibre à des cas de non-équilibre. Dans cette mémoire, l'adsorption des deux systèmes tensioactifs différents a été étudiée, C12E6 de tensioactif non ionique et d'agent tensio-actif ionique CTAB avec suffisamment de sel. Une mesure de la compression de la bulle unique combiné avec une tension superficielle d'équilibre connue (γeq) de valeur permet de déterminer γ(Γ), ce qui est plus précis que les résultats des méthodes traditionnelles. Les concentrations de surface en fonction du temps sont mesurés, ce qui montre que l'adsorption est contrôlée par la diffusion à temps courts.Après avoir montré que l'adsorption est contrôlée par diffusion, nous rapportons la désorption des tensioactifs à partir de l'interface air/eau pour différents systèmes. Les processus de désorption sont confirmées pas être purement limitée par diffusion, indiquant la présence d'une barrière d'énergie. La barrière d'énergie est influencée par la longueur de la chaîne alkyle, et non le type de contre-ion.Dans la deuxième partie de la thèse, nous nous concentrons sur les systèmes d'ADN/tensioactif. Bien que l'interaction entre les tensioactifs cationiques et anioniques polyélectrolyte a été largement étudiée, il reste nécessaire de mieux comprendre le système complexe, en particulier pour rationaliser le choix des tensioactifs pour atteindre une capacité de liaison de l'ADN contrôlable et une faible toxicité pour l'organisme. Dans cette thèse, nous avons lancé l'enquête systématique sur les interactions des deux tensioactifs cationiques avec l'ADN.Le premier tensioactif utilisé est un gemini tensioactifs cationiques 12-2-12∙2Br. Avant de l'utiliser avec l'ADN d'une caractérisation approfondie a été effectuée. L'équilibrage du 12-2-12∙2Br sur une interface air/eau en l'absence d'électrolyte est très lent. Ajout de NaBr affecte peu la cinétique d'adsorption à des temps courts, pendant lesquels l'adsorption de diffusion. Cependant, l'adsorption s'équilibre beaucoup plus rapide. La formation de micelles de tensioactif cationique gemini 12-3-12∙2Br a été étudiée. La concentration micellaire critique (CMC) augmente légèrement avec la température et diminue avec la force ionique. 12-3-12∙2Br interagit fortement avec l'ADN, en raison de l'attraction électrostatique entre les deux et les interactions hydrophobes entre les chaînes alkyles. Sel écrans l'attraction électrostatique, tout en augmentant la longueur d'écartement des Gémeaux tensioactif affaiblit son interaction avec l'ADN.Un autre agent a également été étudié pour sa capacité de liaison à l'ADN et nous présentons une étude systématique sur les interactions entre tensioactif cationique liquide ionique [C12mim]Br et de l'ADN par des techniques expérimentales et de dynamique moléculaire (MD) de simulation. En ajoutant [C12mim]Br, les chaînes d'ADN sont soumis à compactage, des changements conformationnels, avec le changement de charge nette portée par le complexe ADN/tensioactif. simulation de MD confirme les résultats expérimentaux. / Bearing a hydrophilic part and a hydrophobic part, surfactants can adsorb onto interfaces and lower the interfacial tension (γ), thereby enhancing the interfacial properties and leading to the applications in cleaning, surface functionalization, foaming and emulsification. Charged surfactants are also used in biological applications, in particular to extract and purify DNA, or for gene delivery. In this thesis we have studied the adsorption properties of surfactants, both to air/water interfaces and onto DNA to form complexes. The first part of the thesis concentrates on interfacial studies of surfactants. To understand how they work in these applications it is important to know the time-scales of the surfactant adsorption and desorption. Thus it is necessary to investigate the adsorption and desorption kinetics, which are already widely studied. However, traditional studies tend to make many assumptions, for example, extending the applicability of equilibrium relations to non-equilibrium cases. In this dissertation, the adsorption of two different surfactant systems has been investigated, non-ionic surfactant C12E6 and ionic surfactant CTAB with sufficient salt. A single bubble compression measurement combined with a known equilibrium surface tension (γeq) value allows the determination of γ(Γ), which is more accurate than results from traditional methods. The time-dependent surface concentrations are measured, showing that the adsorption is diffusion controlled at short times.Having shown that adsorption is diffusion controlled, we report desorption of surfactants from the air/water interface for different systems. The desorption processes are confirmed not to be purely diffusion-limited, showing the presence of an energy barrier. The energy barrier is influenced by the alkyl chain length, but not the counterion type.In the second part of the thesis we concentrate on DNA/surfactant systems. Although the interaction between cationic surfactant and anionic polyelectrolyte has been extensively studied, there still remains need to further understand the complex system, especially to rationalize the choice of surfactants to reach controllable DNA binding ability and low toxicity to the organism. In this dissertation, we introduced the systematic investigation on the interactions of two cationic surfactants with DNA.The first surfactant used is a cationic gemini surfactant 12-2-12∙2Br. Before using it with DNA a thorough characterization has been carried out. The equilibration of 12-2-12∙2Br onto an air/water interfaces in the absence of electrolyte is very slow. Addition of NaBr hardly affects the adsorption kinetics at short times, during which the adsorption is diffusive. However, the adsorption equilibrates much faster. The micellization of cationic gemini surfactant 12-3-12·2Br has been investigated. The critical micelle concentration (CMC) increases slightly with temperature and decreases with ionic strength. 12-3-12·2Br interacts strongly with DNA, due to the electrostatic attraction between the two and the hydrophobic interactions between alkyl chains. Salt screens the electrostatic attraction, while increasing spacer length of gemini surfactant weakens its interaction with DNA.Another surfactant has also been studied for its DNA binding ability and we present a systematic study on interactions between cationic ionic liquid surfactant [C12mim]Br and DNA by experimental techniques and Molecular Dynamics (MD) simulation. By adding [C12mim]Br, DNA chains undergo compaction, conformational changes, with the change of net charges carried by the DNA/surfactant complex. MD simulation confirms the experimental results.

O 4-Nonilfenol (4-NF) é o principal produto formado a partir da degradação do Nonilfenol etoxilado, surfactante não iônico amplamente utilizado em formulações de uso doméstico e industrial. Objetivou-se neste estudo desenvolver método de quantificação de 4-NF em HPLC; avaliar a remoção de 4-NF em reatores em batelada com co-substratos (etanol, metanol e fumarato) e avaliar a remoção e degradação de 4-NF em Reator Anaeróbio de Leito Fluidificado (RALF) em escala aumentada (20L), bem como caracterizar a comunidade microbiana estabelecida no material suporte por meio das técnicas de PCR/DGGE do gene RNAr 16S e sequenciamento massivo via plataforma Illumina-Miseq®. O RALF foi preenchido com areia como material suporte, operado com Tempo de Detenção Hidráulico (TDH) de 18,2±1,1 horas e alimentado com meio de cultura acrescido de 4-NF PESTANAL® (Sigma-Aldrich®). Análises de monitoramento da concentração de 4-NF e matéria orgânica, bem como, dos parâmetros físico-químicos foram realizadas para avaliar a estabilidade do reator quanto a remoção e degradação do composto de interesse. A operação do reator foi dividida em distintas etapas, contando com inoculação do RALF em circuito fechado, adaptação ao meio de cultura e subsequentes fases com adição de 4-NF. Para reatores em batelada a adição de 4-NF (de 288,97±96,49 a 469,98±182,42 µg L-1) favoreceu a produção média de metano acumulada (de 2.292,3 para 2.744,7 mol, respectivamente) para todos os co-susbtratos testados, todavia, retardou o tempo médio de início da produção (de 15,9 h para 107,9 h), bem como reduziu a velocidade de produção (de 24,4 para 10,9 µmol d-1). Para ensaio com adição de 4-NF e Fumarato foram verificados os maiores valores de produção acumulada de metano (3.163,68±169,17 µmol) e de remoção de DQO (75,52±0,34% para DQO inicial de 1.242,00±27,48 mg L-1), em relação aos demais ensaios com adição de 4-NF. Para a remoção de 4-NF em reatores em batelada os valores não diferiram significativamente. Para o RALF, foram verificadas eficiências médias de remoção de DQO de 90,34±6,1% (Fase I), 94,0±1,2% (Fase II), 97,0±1,3% (Fase III) e 95±1,5% (Fase IV) e 4-NF de 73,2±11,1% (Fase II), 67,3±7,3% (Fase III) e 77,88±8,9% (Fase IV). As diferentes concentrações de 4-NF aplicadas ao RALF não afetaram a eficiência de remoção de DQO e promoveram a seleção dos microrganismos que compuseram a biomassa do leito. Os gêneros mais abundantes identificados no reator sem adição de 4-NF foram Prolixibacter, Geothrix, Klebsiella, Lactobacillus e Geobacter. Os gêneros com maior abundância relativa identificados após adição de 4-NF foram os seguintes: Geothrix, Holophaga, Elusimicrobium, Paludibacter, Lactobacillus, Aeromonas, Pelobacter, Aquaspirillum, Pseudomonas, Delftia, Acinetobacter, Arcobacter, Ignavibacterium, Treponema, Lysinibacillus e Enterococcus. / 4-Nonylphenol (4-NP) is the main product formed in the Nonylphenol ethoxylate degradation, nonionic surfactant used in formulations of domestic and industrial use. The objective of this study was to develop a method to determine 4-NP in HPLC; to evaluate the 4-NP removal in batch reactors with co-substrates (ethanol, methanol and fumarate) and removal and degradation of 4-NP in anaerobic Fluidized Bed Reactor (AFBR) on an enlarged scale (20L), as well as characterize the microbial community established in the support material by PCR / DGGE techniques of the 16S RNAr gene and massive sequencing by the Illumina-Miseq® platform. The AFBR was filled with sand as carrier material, operated with Hydraulic Retention Time (HRT) of 18.2±1.1 hours and fed with synthetic sewage plus 4-NP PESTANAL® (Sigma-Aldrich®). Monitoring of the 4-NP concentration and organic matter, as well as physical-chemical parameters were performed to evaluate the stability of the reactor for the removal and degradation of the compound of interest. Reactor operation was divided into different stages, with inoculation of the RALF in closed circuit, adaptation to the culture medium and subsequent phases with 4-NF addition. The addition of 4-NP (from 288.97±96.49 to 469.98±182.42 µg L-1) in batch reactors favored the average accumulated methane production (from 2,292.3 to 2,744.7 µmol, respectively) for all tested co-susbtrates, however, delayed the mean time to start production (from 15.9 h to 107.9 h), as well as reduced production rate (from 24.4 to 10.9 µmol d-1). The highest accumulated values of methane production (3,163.68 ± 169.17 µmol) and COD removal (75.52±0.34% for the initial COD of 1,242±27.48 mg L-1) were verified for the addition of 4-NP and Fumarate, compared to the other tests with addition of 4-NP. For the 4-NP removal in batch reactors the values did not differ significantly. Mean values of COD removal for the AFBR were 90.34±6.1% (Phase I), 94.0±1.2% (Phase II), 94.0±1.2% (Phase III) and 97.0±1.3% (Phase IV) and 4-NF of 73.2±11.1% (Phase II), 67.3±7.3% (Phase III) and 77.88±8.9% (Phase IV). Different concentrations of 4-NP applied to the AFBR did not affect the COD removal efficiency and promoted the selection of the microorganisms that composed the bed biomass. The most abundant genera identified in the reactor without addition of 4-NP were Prolixibacter, Geothrix, Klebsiella, Lactobacillus and Geobacter. The genotypes with the highest relative abundance identified after addition of 4-NP were as follows: Geothrix, Holophaga, Elusimicrobium, Paludibacter, Lactobacillus, Aeromonas, Pelobacter, Aquaspirillum, Pseudomonas, Delftia, Acinetobacter, Arcobacter, Ignavibacterium, Treponema, Lysinibacillus and Enterococcus.

<p style="text-align: justify;">Mikrokapsulacija je tehnika kojom se nestabilne, međusobno inkompatibilne i biolo&scaron;ki aktivne supstance prevode u stabilniji oblik, ili se omogućuje njihovo kontrolisano i ciljano oslobađanje. Osobine formiranih mikrokapsula, kinetika i mesto otpu&scaron;tanja inkapsuliranih materija zavise, pre svega, od njihovog omotača. Savremene tendencije razvoja prehrambenih proizvoda i proizvoda farmaceutske i kozmetičke industrije, su sve vi&scaron;e usmerene ka upotrebi prirodnih i biorazgradivih polimernih materija za formiranje omotača mikrokapsula.<br />Cilj ove disertacije je mogućnost primene hitozana, netoksičnog, biorazgradivog derivata hitina, kao materije omotača mikrokapsula sa uljnim sadržajem. S obzirom na njegovu slabu povr&scaron;insku aktivnost, istraživanja su usmerena na primenu interakcija hitozana sa suprotno naelektrisanim jonskim povr&scaron;inski aktivnim materijama (PAM) u vodenim rastvorima, kao mehanizmu za njegovo deponovanje na graničnoj povr&scaron;ini ulje/voda.<br />Primenom različitih metoda (tenziometrija, viskozimetrija, turbidimetrija, merenje elektroforetske pokretljivosti) interakcije hitozana sa natrijum-dodecil-sulfatom (SDS) i natrijum-lauriletar-sulfatom (SLES) su detaljno ispitane. Definisane su promene kako na granici faza, tako i unutar rastvora, a mehanizam formiranja kompleksa hitozan/PAM različitih osobina je u potpunosti razja&scaron;njen. Utvrđeno je da do formiranja stabilnog koacervata dolazi pri masenom odnosu hitozan:SLES 1:2 i hitozan:SDS 1:2.<br />Ispitivanje uticaja interakcije hitozan-PAM na osobine emulzionih sistema tipa ulje u vodi (veličina i raspodela veličina kapi, stabilnost) omogućilo je odabir hitozan-SLES sistema kao omotača pogodnog za dobijanje mikrokapsula uljnog sadržaja. Na osnovu ovih rezulatata kao uljna faza odabrani su trigliceridi srednje dužine ugljovodoničnih lanca (TSDL). Su&scaron;enjem emulzija primenom spray drying postupka dobijene se mikrokapsule uljnog sadržaja sa vitaminom E i ispitan je uticaj umreživača na njihove osobine. Karakterizacijom dobijenih mikrokapsula (određivanje sadržaja vlage, ispitivanje morfologije povr&scaron;ine, efiksanost inkapsulacije vitamina E, kinetika otpu&scaron;tanja vitamina E u in vitro uslovima) zaključeno je da na osobine mikrokapsula utiče vrsta i koncentracija umreživača. Mikrokapsule čiji omotač nije umrežen pokazale su najbolje karakteristike.</p> / <p>Microencapsulation is a technique that unstable, incompatible and biologically active substances converted to a more stable form, or allow their controlled and targeted release. The properties of formed microcapsules, kinetics and the place of release of encapsulated substances, primarly depend on their shell characteristic. Modern trends in the development of food products and products of the pharmaceutical and cosmetic industries are increasingly focused on the use of natural and biodegradable polymeric materials for coatings.<br />The aim of this dissertation is to investigate the possibility of using chitosan, non-toxic and biodegradable chitin derivative, as a shell material of microcapsules with oil content. Due to its low surface activity, the research is focused on the utilization of chitosan interactions with opositly charged ionic surfactants (sodium dodecyl sulfate (SDS) and sodium lauryl ether sulfate (SLES)) in aqueous solutions as mechanisms for its depositing at the oil/water interface.<br />Based on detailed investigation of interactions in the chitosan-ionic surfactant systems using different methods (tensiometry, viscometry, turbidimetry, measurement of electrophoretic mobility), changes have been defined both at the interface and within the bulk, as well as the mechanism of formation of the coacervate phase. It has been determined that at chitosan:SLES and chitosan:SDS mass ratio of 1:2 stabile coacervate were formed.<br />An investigation of the influence of interaction on the properties of oil-in-water emulsion systems (size and distribution of droplet size, stability) enabled the chitosan-SLES system to be selected as a shell suitable for obtaining microcapsules of the oil content. Also, based on these results, medium-chain triglycerides were selected as the oil phase of the emulsion.<br />Microcapsules with vitamin E were obtained by spray drying of emulsions stabilized with chitosan/SLES complex. The influence of the crosslinker on the properties of microcapsules was investigated. Characterization of obtained microcapsules (moisture content determination, investigation of the surface morphology, efficiency of the vitamin E encapsulation, release in vitro kinetics of vitamin E) showed that type and concentration of crosslinking agents had influences the properties of microcapsules. Microcapsules without crosslinking agents have the most suitable characteristics.</p>

A lixiviação de elementos tóxicos presentes nas cinzas de carvão causa contaminação no meio ambiente e é, por isso, motivo de grande preocupação. Ensaios em batelada e em coluna de leito fixo foram realizados para avaliar a estabilização de As, Cr, Mo e Se em cinzas leve de carvão modificadas com orgânosilano (OS) e surfactante de amônio quaternário (SF). As cinzas leve utilizadas foram coletadas na Usina Termelétrica da Figueira, localizada na cidade de Figueira, Estado do Paraná. Nos ensaios em batelada, em primeiro lugar, avaliou-se a influência da relação massa de cinzas/volume de água na concentração dos elementos lixiviados das cinzas não tratadas. Posteriormente, determinou-se o pH, a condutividade e as capacidades de imobilização dos elementos tóxicos presentes nas cinzas após a modificação. As reduções de concentração usando OS foram de 89%, 77%, 42% e 11% para Cr, Mo, As e Se, respectivamente. Quando SF foi utilizado para o tratamento das cinzas, a redução de concentração nos lixiviados foi superior a 60% para todos os elementos. As cinzas tratadas foram caracterizadas em relação ao ponto de carga zero, morfologia, grupos funcionais, mineralogia e hidrofobicidade. As superfícies das cinzas tratadas com OS e SF apresentaram carga superficial positiva em água. A composição mineralógica e a morfologia das cinzas não foram alteradas após o tratamento, enquanto mudanças nos grupos funcionais foram observadas. Esse resultado corroborou com o observado nos testes de hidrofobicidade onde, as cinzas tratadas com OS e SF na proporção 1:10 foram classificadas como material extremamente hidrofóbico e na proporção 1:100 foram classificadas como material fortemente hidrofóbico, confirmando que foi efetivo o tratamento das cinzas com os agentes imobilizadores. Na segunda etapa do estudo foram realizados três ensaios de lixiviação em colunas contendo cinzas de carvão e solo coletado na região da Usina Termelétrica da Figueira. Nos ensaios foram usadas cinzas não tratadas, cinzas tratadas com OS e cinzas tratadas com SF nas diluições de maior efetividade selecionadas pelos ensaios em batelada. Nas colunas foi aplicado um volume de chuva ácida sintética simulando a precipitação que ocorre na região. Na coluna com cinzas tratadas com OS ocorreu redução considerável na concentração de As e principalmente do Cr. Após o tratamento com SF, as concentrações de As e Cr reduziram aproximadamente 30%. Em ambos os tratamentos, as concentrações de Mo e Se também foram reduzidas. Os resultados evidenciaram que tanto o orgânosilano, quanto o surfactante podem ser utilizados como agentes imobilizadores para a retenção de elementos tóxicos presentes em cinzas de carvão. / The leaching of toxic elements in coal ash causes contamination of the environment and is therefore of great concern. Batch and column tests were performed to evaluate the stabilization of As, Cr, Mo and Se in fly ash modified with organosilane (OS) and quaternary ammonium surfactant (SF). The fly ashes used were collected at the Figueira Thermoelectric Plant, located in the city of Figueira, State of Paraná. In the batch tests, first, the influence of ash / volume ratio on the concentration of the leached elements of the untreated ash was evaluated. Subsequently, the pH, conductivity and immobilization capacities of the toxic elements present in the ashes after the modification were determined. The reductions in the concentrations of toxic elements using OS were 89%, 77%, 42% and 11% for Cr, Mo, As and Se, respectively. When SF was used for ash treatment, the concentration reduction in the leachates was greater than 60% for all elements. The treated ash was characterized in relation to zero charge point, morphology, functional groups, mineralogy and hydrophobicity. OS and SF treated ash surfaces showed a positive surface charge in water. The mineral composition an morphology of the ashes was not altered after treatment, while changes in the functional groups were observed. This result corroborated with that observed in the hydrophobicity tests, where ashes treated with OS and SF in the proportion 1:10 were classified as extremely hydrophobic material and in the proportion 1: 100 were classified as strongly hydrophobic material, confirming that the treatment of the ashes with immobilizing agents were efficient. In the second stage of the study three leaching tests were carried out on columns containing coal ash and soil collected in the Figueira Thermoelectric Power Plant region. In the tests, untreated fly ash, OS treated fly ash and SF treated fly ash were used at the most effective dilutions selected by batch tests. In the columns a synthetic acid rain was applied simulating the precipitation that occurs in the region. In the column with ash treated with OS there was a considerable reduction in the concentration of As and especially of Cr. After treatment with SF, concentrations of As and Cr reduced approximately 30%. In both treatments, the concentrations of Mo and Se were also reduced. The results showed that both the organosilane and the surfactant can be used as immobilizers for the retention of toxic elements present in coal ash.

A solubilização de solutos não iônicos através de um processo de partição entre água e a pseudo-fase micelar de tensoativos não iônicos foi estudada para álcoois secundários etoxilados com grau de etoxilação variando entre 7 e 40. Mostrou-se que o coeficiente de incorporação micelar, Ks, é independente do grau de etoxilação o que corrobora a hipótese de que a partição ocorre entre água e o núcleo hidrocarbônico da micela, que não é alterado pelo aumento do número de grupos de óxido de eteno na cabeça polar do tensoativo. O uso de relações lineares de energia livre, LSER, para a predição da capacidade de solubilização de álcoois secundários etoxilados forneceu, através de regressão múltipla linear a seguinte LSER como melhor modelo: log Ks = -0,42 + 1,21E - 1,73S -0,40A - 1,13B + 3,01V com R2 = 0,98 e valor de teste F de 1390. Nesta equação, V é o volume molar do soluto, A e B são a capacidade do soluto de atuar como doador e aceptor de pontes de hidrogênio, E é a refração molar em excesso e S representa a capacidade do soluto de interagir com o meio de solubilização através de interações do tipo dipolo-dipolo e dipolo-dipolo induzido. Mostrou-se que processos de limpeza aplicados à remoção de sujidades de tecidos e superfícies sólidas não estão correlacionados ao mecanismo de solubilização descrito por um processo de partição. A dependência da redução de tensão interfacial com o grau de etoxilação sugere que a eficiência de limpeza, para superfícies sólidas e para tecidos, está correlacionada de maneira direta, mas não linear, com a capacidade do tensoativo de concentrar-se na interface \"sujidade-solução aquosa de tensoativo\" reduzindo assim a tensão interfacial entre os dois meios. / The solubilization of non-ionic solutes via partitioning between water and the micellar pseudophase of non-ionic surfactants was evaluated for a series of secondary alcohol ethoxylates with hydrophile length varying from 7 to 40 ethylene oxide units. It was demonstrated that the micellar incorporation constant, Ks, is not dependent on the hydrophile length of the surfactant. The results obtained in this study support the hypothesis that the partitioning between water and the micellar core is not disturbed by the etheylene oxide hydrophilic groups. Linear solvation free energy relationships, LSER, were used to model the ability of the surfactants to solubilize non-ionic compounds. Multiple linear regression analysis provided the following LSER with R2 of 0.98 and F value of 1390: logK = -0,42 + 1,21E - 1,73S - 0,40A - 1,13B + 3,01V. In this LSER, V is a descriptor of solute molar volume, A and B capture the overall ability of the solute to act as a hydrogen bond donor and acceptor, E is the solute excess molar refraction and S is a descriptor of the ability of the solute to interact via dipole-dipole and dipole-induced dipole interactions with its surroundings. It was demonstrated that hard and soft surface cleaning efficiencies are not correlated with the solubilization process. It was shown, however, that the change in interfacial tension caused by the change in the hydrophile portion of the surfactants has a direct, but non-linear impact on the cleaing properties of aqueous solutions containing these surfactants.

Atualmente, muitas pesquisas são realizadas com o objetivo de desenvolver novas formulações, sejam elas cosméticas ou farmacêuticas baseadas em nanocarreadores. Devido às suas características favoráveis, nanopartículas poliméricas são propostas como veículos tópicos, principalmente para fotoprotetores, com o intuito de prolongar o tempo de resistência dos filtros na pele, evitando assim o processo de fotodegradação. Filtros solares, de uma maneira geral, são formas cosméticas emulsionadas as quais são termodinamicamente instáveis. Para evitar este processo é necessário um componente capaz de manter esta estabilidade, isto é, um tensoativo. Em alguns sistemas, polissacarídeos ou proteínas atuam como tensoativos/estabilizantes em emulsões óleo/água (O/A). Neste contexto, a proposta deste trabalho é introduzir amidos modificados (catiônicos e aniônicos) e hidrolisados como tensoativo em uma formulação para a encapsulação da benzofenona-3 com uma matriz polimérica de poli(?-caprolactona) (PCL), avaliando a influência deste estabilizante nas características físico-químicas das nanopartículas. As nanopartículas foram preparadas mediante a técnica de deposição interfacial do polímero pré-formado, empregando-se um planejamento de experimentos de mistura. Previamente, foram avaliadas as condições da hidrólise enzimática, via planejamento de experimentos, para verificar quais parâmetros (tempo e concentração da enzima) maximizariam este processo reduzindo de maneira satisfatória a massa molar do amido para posterior aplicação como estabilizante. Foram realizados testes de tensão para avaliar a capacidade tensoativa das soluções aquosas dos amidos hidrolisados, para posterior aplicação na formulação de nanopartículas. Os resultados indicaram que dois lotes de amido, de quatro avaliados, podem ser empregados como tensoativos na formulação de nanopartículas, sem alterar significativamente propriedades, como diâmetro, polidispersão e teor de encapsulação. / Currently, many researches are conducted with the aim of developing new formulations, whether cosmetic or pharmaceutical-based nanocarriers. Due to its favorable characteristics, polymeric nanoparticles are proposed as topics vehicles, mainly for sunscreens, in order to prolong the resistance of the filters on the skin, thus preventing the photodegradation process. Sunscreens, in general, are emulsified cosmetic forms which are thermodynamically unstable. To avoid this process requires a component capable of maintaining this stability, i.e., a surfactant. In some systems, polysaccharides or proteins act as surfactants/stabilizers in oil-water emulsions (O/W). In this context, the purpose of this work is to introduce modified starches (cationic and anionic) and hydrolyzed as surfactant in a formulation for the encapsulation of benzophenone-3 with a polymer matrix of poly(?-caprolactone) (PCL), evaluating the influence of this stabilizer the physical-chemical characteristics of nanoparticles. The nanoparticles were prepared by interfacial deposition pre-formed polymer technique, using a design of experiments like mixture. Previously evaluated the conditions of enzymatic hydrolysis, by design of experiments to determine which parameters (time and enzyme concentration) to maximize this process satisfactorily reducing the molecular weight of the starch for subsequent use as a stabilizer. Tension tests were conducted to assess the ability of surfactant aqueous solutions of hydrolyzed starch for application in the formulation of nanoparticles. The results indicated that two batches of starch, four-valued, can be employed as a surfactant in the suspension of nanoparticles, without significantly altering properties such as diameter, polydispersity and the content of encapsulation.