A tese consistiu no estudo por técnicas reológicas da dinâmica de géis e dispersões da gliadina do glúten do trigo em meios de dimetilsulfóxido (DMSO), dimetilformamida (DMF) e formamida puros e em suas misturas com a água. Investigou-se o efeito da temperatura e das concentrações das espécies componentes (proteína e constituintes dos sistemas solventes) sobre o comportamento de fluxo e de deformação dos sistemas. Foram realizados testes em regime estacionário, ensaios transientes e ensaios dinâmicos (oscilatórios). A caracterização da proteína nos diversos meios foi realizada através de técnicas de espalhamento de luz dinâmico e estático e de espalhamento de raios X em baixos ângulos. Esses recursos permitiram descrever a distribuição de populações da proteína nos géis e dispersões, em suas formas livres ou associadas, assim como estimar aspectos de tamanho e mobilidade a partir da determinação dos raios hidrodinâmicos e coeficientes de difusão. As composições de aminoácidos da gliadina, na fração bruta e em uma fração isolada em meio etanólico, foram determinadas por técnicas de CLAE Cromatografia Líquida de Alta Eficiência. Um isolamento preliminar das sub-frações de gliadina foi obtido por outra técnica cromatogrática (FPLC Fast Polymer Liquid Chromatography). Foram ainda desenvolvidos estudos relativos ao efeito de gliadina sobre a bicamada lipídica de vesículas gigantes de fosfolipídio, através da técnica de aspiração por micropipetas, com monitoramento por vídeo-microscopia. O objetivo foi o de se verificar o eventual efeito da proteína sobre a constante de elasticidade, kc, da bicamada. Os resultados obtidos podem ser resumidos como se segue: a) o comportamento viscoelástico apresentado pela gliadina mostrou dependência com a natureza e a composição do meio de dispersão. Foi verificada a ocorrência de comportamento tixotrópico ou reopéxico como função da temperatura e um comportamento cíclico para a viscosidade em função do tempo. b) foi possível correlacionar alguns aspectos da estrutura molecular e polaridade do solvente com a maior ou menor capacidade de formação de gel de gliadina: solventes com regiões apolares mais expressivas, como DMSO e DMF (ε= 47,24 e 38,25, respectivamente) induzem a formação de géis rígidos, enquanto um composto como formamida, destituído de um domínio apolar minimamente significativo e ε maior que o da água (ε = 84), tem capacidade significativamente menor de promover a formação de géis com as mesmas características de rigidez. c) os géis são formados por unidades com raios de giro da ordem de 15Å, além de agregados de tamanhos bem maiores. Considerando-se a massa molar média de 32 350 g/mol para a gliadina em nossa amostra, é de se supor que a proteína encontre-se muito compactada no gel (considere-se que lisozima, com massa molar muito menor, igual a 14300 g/mol, possui raio de giro nesse mesmo valor). Um modelo de enovelamento interpenetrante, proposto em nosso grupo através de métodos de dinâmica molecular para a conformação da gliadina, seria assim compatível com essas observações experimentais. d) gliadina ω, seletivamente extraída por tratamento com etanol, mostrou-se capaz de reduzir a elasticidade de membranas de microvesículas de fosfolipídios, aumentando o valor de sua constante de curvatura kc. Um efeito de saturação foi observado, para razões de massa gliadina/DOPC ~2-3%. e) coeficientes de difusão para dispersões de gliadina são da ordem de 10-10 cm2.s-1, com raios hidrodinâmicos na faixa nm-µm. Duas populações dinamicamente distintas foram identificadas nos géis de gliadina. f) o grau de polidispersão e o tamanho dos agregados mostraram dependência com a concentração da proteína nos géis: são gerados agregados menores (diminuição da massa molar média) em tamanhos mais uniformes (menor polidispersão), com o aumento da concentração de gliadina. Essa mesma tendência de variação é observada como função do tempo, indicando a ocorrência de rearranjos estruturais na fase de envelhecimento dos géis. / The thesis consisted in a rheological study of the dynamics of gels and dispersions of gliadin from wheat gluten in pure dimethylsulfoxide, dimethylformamide or formamide and in their mixtures with water. The effect of temperature and that of the concentration of the component species (protein and solvent constituents) on flow behavior and deformation were evaluated. Steady-state, transient and dynamical (oscillatory) tests were performed. Protein characterization in the various media was performed through dynamic and static light scattering and small angle X ray scattering techniques. The application of techniques allowed to describe the distribution of protein populations in the gels and dispersions, in their free and associated forms, as well as to estimate their size and mobility, through the determination of the hydrodynamical radii and diffusion coefficients. The amino acid compositions of gliadin, both in the crude protein and in an isolated fraction in ethanol, were determined by HPLC technique. A preliminary isolation procedure of gliadin sub-fractions was achieved by another chromatographic technique (FPLC). The effect of gliadin on the phospholipid bilayer of giant vesicles was studied through the technique of micropipet aspiration coupled to videomicroscopy. The aim was to verify the possible effect of protein on the elasticity constant, kC of the bilayer. Results obtained can be summarized as follows: a) the viscoelastic behavior presented by gliadin was found to be dependent on the nature and composition of the dispersing media. Temperature-dependent tixotropic or rheopexic behavior were observed, as well as a cyclic behaviour for viscosity as a function of time. b) it was possible to correlate some aspects of solvent molecular structure and polarity with its greater or lesser capacity of gel formation: solvents with more expressive apolar regions, such as DMSO and DMF (ε = 47,24 and 38,25, respectively) induce formation of rigid gels, whereas a compound such as formamide, devoid of a minimally significant apolar domain and ε greater than that of water (ε = 84), is significantly less able to promote gel formation with the same characteristics of rigidity. c) gels are formed by units with gyration radius around 15Å and also by aggregates of greater size. Considering that the average molar mass in our sample for gliadin is 32350, one can assume that the protein is very densely packed in the gel (consider for instance that lysozyme, with a much lower molar mass, 14300 g/mol, has a gyration radius of this same size). A compact, interpenetrating folding model for gliadin, developed in our group through molecular dynamics, is compatible with such experimental observations. d) ω gliadin, selectively extracted in ethanol, was found to be able to reduce membrane elasticity of phospholipid microvesicles, by increasing its elastic curvature constant kC. A saturation effect was observed, for a mass ratio as low as gliadin/DOPC ~2-3%. e) diffusion coefficients for gliadin dispersions are circa 10-10 cm2.s-1, with hydrodynamical radii in the nm-µm range. Two dynamically distinct populations are identified in the gliadin gels. f) gel polydispersity and aggregate size depend on protein concentration: smaller aggregates (lower average molar mass) of more uniform sizes are produced for increasing gliadin concentration. Variation with time followed the same pattern, indicating that structural rearrangements take place during gel aging.

Dans cette thèse, on a étudié les propriétés rhéologiques et moussantes de phases de bicouches, de type lamellaire et éponge, en utilisant le système expérimental SDS/hexanol/saumure. On a également préparé des mousses avec ces deux phases de bicouches, dont on a étudié la stabilité et les mécanismes d’évolution dans le temps. En premier lieu, les propriétés rhéologiques de la phase éponge ont été examinées. Les échantillons ayant une fraction volumique de membrane phi ≥ 0.08 se comportent comme des fluides Newtoniens. Avec les moins concentrés, phi = 0.05 et 0.024, un changement de viscosité est observé à environ 1000 et 100 s⁻¹, respectivement. Ce changement pourrait être lié à une transition de la phase éponge vers une phase lamellaire induite par cisaillement. Les changements de viscosité qui suggèrent une transition éponge-lamellaire induite par l’écoulement ont été plus facilement détectés pour l'échantillon de fraction volumique phi = 0.024. Pour cet échantillon, il a été constaté qu’à des températures plus basses ou lors de l’ajout d’un polymère hydrosoluble (PEG), la variation de la viscosité liée à la transition de phase éponge-lamellaire se produit à des valeurs inférieures de la vitesse de cisaillement. L’étude des propriétés rhéologiques de la phase lamellaire a ensuite été menée. Les expériences ont révélé le comportement de gel faible des échantillons. A une fréquence de 10 rad/s et dans un intervalle de température compris entre 5 à 50 °C, il n’y a aucun changement perceptible des modules G’ et G’’, donc pas de transition de phase, sauf pour les échantillons les moins concentrés : dans ce cas, la température a un effet plus marqué, et la structure lamellaire évolue probablement. Lorsque le taux de cisaillement augmente, il a été observé que les échantillons avec phi ≥ 0.10 présentent une forte augmentation de la viscosité à partir d’une valeur seuil du taux de cisaillement. Cette observation, combinée avec des résultats de Rhéo-SAXS, a permis de conclure qu’il y a une transition vers une phase de vésicules (ou oignons) induite par l’écoulement. Les expériences de Rhéo-SAXS ont montré que, après l’arrêt du cisaillement, la phase de vésicules relaxe vers la phase lamellaire initiale au bout d’un temps typique d’une demi-heure. Enfin, des mousses ont été obtenues par incorporation de bulles d’air dans les phases lamellaire et éponge précédemment étudiées. Les mousses faites avec les phases lamellaires présentent une grande stabilité, probablement en raison de la viscosité élevée de ces gels. De plus, ces gels présentent des contraintes seuils d’écoulement faibles. Lorsque les bulles sont petites, la contrainte seuil est supérieure à la contrainte de pesanteur sur les bulles de la mousse (force d’Archimède). Mais ces bulles grossissent avec le temps (mûrissement dû aux différences de pression de Laplace entre bulles) et lorsque la contrainte de pesanteur dépasse la contrainte seuil du gel, le drainage de la mousse commence. On a constaté que la taille des bulles évoluait avec le temps en suivant une loi de puissance. Cependant, l’exposant (≈ 0.25) est plus petit que ceux trouvés pour le mûrissement d’Ostwald (0.333, valable pour des bulles isolées) ou le mûrissement des mousses (0.5). Le fait que l’exposant trouvé soit plus petit pourrait être lié à la réorientation des domaines lamellaires lors du mûrissement. Enfin, les mousses préparées avec des phases éponge présentent une faible stabilité probablement due aux passages internes entre bicouches qui forment la structure éponge, passages qui pourraient faciliter la coalescence des bulles. Deux scénarii ont été détectés lors de l’évolution de ces mousses: à basse fraction volumique de membrane, l’effondrement de la mousse commence pendant son drainage, alors que les mousses faites avec les échantillons les plus concentrés ont le temps de mûrir avant de s’effondrer. / In this thesis a study of the rheological and foaming properties of the lamellar and sponge phases of the SDS/hexanol/brine system was performed. Shear rate and temperature sweeps were done to analyze the rheology of the lamellar and sponge phases, adding frequency sweeps for the lamellar phase samples. Also, foamability and foam stability tests of foams made with these two phases were done. Sponge phase samples with membrane volume fractions phi ≥ 0.08 showed a Newtonian behavior, whereas in the less concentrated ones, phi 0.05 and 0.024, a change in viscosity was seen at shear rate values near to 1000 and 100 s ⁻¹, respectively. This change can be linked to a shear induced transition sponge to lamellar phase. Results indicate that temperature and the addition of the hydrosoluble polymer PEG affect the shear rate value at which this transition occurs. Lamellar phase samples with phi ≥ 0.10 presented a sharp increase in viscosity at intermediate shear rate values. The standard rheology technique together with Rheo-SAXS experiments allowed us to infer that there is a shear induced phase transition to vesicle phase. Rheo-SAXS data confirmed that the average interlamellar vesicle phase decreases by the effect of shear rate, and, when shear is stopped, the vesicle structure is relaxed and goes back to the lamellar phase after certain time. Foams made with lamellar phase samples showed a high stability and it was found that the time evolution of the bubble diameter follows a power law equation with exponents smaller than those reported for coarsening and Ostwald ripening. The small values of these exponents seem to be related with orientation defects of the liquid crystalline phase. On the opposite, the foams made with the sponge phase samples presented poor stability, as a possible consequence of the passages that form their structure that could facilitate coalescence of bubbles.

Les mortiers colles se composent essentiellement de ciment, de sable, de charges minérales et d'une variété d'additifs (éthers de cellulose, entraînant d'air, latex) et sont utilisés pour coller des carreaux céramique (et d'autres pièces comme la pierre, le verre, etc.) aux substrats. Ils sont généralement appliqués dans une grande surface sur le substrat sous la forme de nervures sur lesquelles les carreaux sont mis. Afin d'obtenir une bonne performance, il est important que les propriétés rhéologiques du mortier permettent un bon contact entre les carrelages, même après plusieurs minutes (temps ouvert) d'exposition aux conditions ambiantes, soit à l'intérieur soit à l'extérieur des bâtiments. A cet effet, il est nécessaire d'éviter la formation d'une couche rigide et/ou sèche à l'interface mortier-air, qui peut être difficile à déformer ou à humidifier correctement la surface de la dalle. Comme le contact initial entre le mortier et le carrelage est la première étape pour le développement des propriétés adhésives entre les matériaux, une bonne compréhension de l'évolution des propriétés rhéologiques à l'interface air-mortier est d'une grande importance pour les producteurs de mortier et les utilisateurs. Dans ce contexte, cette thèse a d'abord développé des méthodes d'évaluation des propriétés interfaciales et une technique microscopique pour visualiser le contact. Ensuite, ces techniques combinées à des essais de tack test/ squeeze et à des procédés rhéologiques déjà existants peuvent être utilisé pour évaluer comment des additifs polymères tels que l'éther de cellulose influent sur les propriétés rhéologiques du mortier adhésif dans le volume et à l'interface pour mieux comprendre les propriétés adhésives. Et enfin, avec l'utilisation de la RMN, ces propriétés pourraient être corrélées avec l'évolution de la distribution de l'eau. / Adhesive mortars consist basically of cement, sand, mineral fillers and a variety of additives (cellulose ethers, air-entraining, latex) and are used to glue ceramic tiles (and other pieces like stone, glass etc) to substrates. They are usually applied in a large surface on the substrate in the form of ribs on which tiles are put. In order to obtain a good performance it is important that when the tile is installed, the mortar rheological properties allow for good contact between them, even after several minutes (open time) of exposure to ambient conditions either at internal or external building areas. For this purpose, it is necessary to avoid the formation of a rigid and/or dry layer at the mortar-air interface, which may be difficult to be deformed or wet the tile surface properly. As the initial contact between mortar and tile is the first step for the development of adhesive properties between the materials, a good comprehension of the rheological properties evolution at the air-mortar interface is of great importance for mortar producers and users. In this context, this thesis firstly developed methods to evaluate interfacial properties and a microscopical technique to visualize the contact. Then, those techniques combined with already existent squeeze flow/tack test and rheological methods can be used to evaluate how polymer additives such as cellulose ether influence the adhesive mortar rheological properties in the volume and at interface to further understand the adhesive properties. And finally, with the use of NMR, those properties could be correlated with water distribution evolution.

Metallo-supramolecular hydrogels have interesting dynamic properties for many applications. We report a simple method for synthesizing copper-based polymer hydrogels made from nontoxic poly(methyl vinyl ether-alt-maleic anhydride) (PVM-alt-MA) in the absence or presence of added dicarboxylates, such as adipate and terephthalate. We utilize metal-polycarboxylate backbone and carboxylate spacer ligands between polymers strands engineered via non-covalent metal ion coordination. Rheological measurements revealed that the mechanical stability of the hydrogels was enhanced by the addition of supplementary dicarboxylate ligands. The optimal ratio of polymer to dicarboxylate to Cu2+ was 10:4:2.5. Our scanning electron microscope (SEM) and Cryo-SEM imaging and physical adsorption measurements revealed the formation of pores. The Brunauer–Emmett–Teller (BET) surface area of the dried hydrogels increased from 177.96 m2 g−1 in a dried hydrogel without added dicarboxylate to 646.90 and 536.44 m2 g−1 with the addition of adipate and terephthalate, respectively. The pore volume increased as well. Separation of CO2 from post-combustion flue gases is important for environmental and economic sustainability. The PVM-alt-Na-MA:adipate:Cu2+ hydrogels are promising material for post-combustion CO2 separation. At normal conditions (298 K and 1 bar), the PVM-alt-Na-MA:adipate:Cu2+ hydrogel samples with 10:4:2.5 ratio, showed notable CO2/N2 selectivity of 78.46 and a high CO2/CH4 selectivity reaching 26.09 at 1 bar. Additionally, we investigated in detail the effect of transition metal ion on the rigidity and structure of hydrogels using Al3+, Fe3+, Cu2+, Ni2+, Zn2+, and Co2+. We also studied the effect of using tricarboxylate spacer ligands such as nitrilotriacetic (NTA) and trisodium citrate or tetracarboxylate such as ethylenediaminetetraacetic acid (EDTA). It is important to mention that one of the main advantages of our facile synthesis method is being simple and can be scaled up for commercial applications. For scaling up the synthesis of hydrogels, we utilized a filling machine that is able to increase the amount of hydrogel aliquots with variable volume. Silver-based hydrogels showed significant antibacterial activity, due to the presence of silver nanoparticles. We utilized a filling machine for application of amorphous wound dressing. The optimization of the conditions of the filling enabled us to scale up the synthesis and the filling process.

京都大学 / 0048 / 新制・論文博士 / 博士(農学) / 乙第13247号 / 論農博第2872号 / 新制||農||1070(附属図書館) / 学位論文||H31||N5171(農学部図書室) / (主査)教授 松村 康生, 教授 丸山 伸之, 教授 谷 史人 / 学位規則第4条第2項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

<div>Starch pasting behavior greatly influences the texture of a variety of food products such as canned soup, sauces, baby foods, batter mixes etc. The annual consumption of starch in the U.S. is 3 million metric tons. It is important to characterize the relationship between the structure, composition and architecture of the starch granules with its pasting behavior in order to arrive at a rational methodology to design modified starch of desirable digestion rate and texture. </div><div> In this research, polymer solution theory was applied to predict the evolution of average granule size of starch at different heating temperatures in terms of its molecular weight, second virial coefficient extent of cross-link and electrostatic interaction within a granule. Evolution of granule size distribution of normal maize starch (NMS) and NMS crosslinked to different extents with sodium trimetaphosphate, waxy rice starch, normal rice starch and normal potato starch when subjected to heating at a rate of 15 C/min to 65, 70, 75, 80, 85 and 90 C was characterized using static laser light scattering. As expected, granule swelling was more pronounced at higher temperatures and resulted in a shift of granule size distribution to larger sizes. Most of the swelling occurred within the first 10 min of heating except for potato starch. Novation 1600 (Modified Potato Starch) is also found to shift to larger sizes at longer holding times and higher temperatures, but this shift is found to be gradual and for penpure 80, even at 60 C, the size distribution shifts to smaller sizes at longer holding times indicating breakup of the granule. </div><div> The structure of normal maize starch was characterized by cryo scanning electron microscopy. The number of crosslinks in the starch network was inferred from equilibrium swelling. This is related to peak viscosity and zeta potential of granule for NMS and its crosslinked starches. Chemical potential profile as well as the temperature profile within the granule at different times were predicted which were then employed to evaluate the granule size at different times. The proposed model is able to describe the swelling behavior of different varieties of starch and also the effect of crosslinking. </div><div> The viscoelasticity for different starch types, heating rates, and heating temperatures were characterized. A methodology to predict the storage modulus of starch paste due to granule swelling, given the physical properties of the starch granule is presented. In high-volume fraction regime, classical model for foam rheology enabled calculation of limiting storage modulus for different starches. By scaling the storage modulus with limiting storage modulus, the storage modulus of a wide range of starches forms a master curve. This master curve when employed along with the swelling model resulted in the successful prediction of development of texture for different types of starches. </div><div> In low-volume fraction regime (below 65%), Stokesian dynamics simulations are used to predict the viscoelasticity of polystyrene micro particles and fractionated starch suspension and compared with experiments. Predicted values of storage modulus from stokesian dynamics simulation at 4 HZ for different volume fractions of monodispersed polystyrene spheres of two different sizes namely 25 and 116 micrometer compared well with experimental values. Stokesian dynamics also describes the storage modulus of fractionated starch granules for volume fractions between 0.4 - 0.5</div><div> The average granule size of starch in presence of sucrose was initially increasing and then decreasing with maximum swelling at 5% and 10% sucrose concentration for NMS and WRS. The average granules size continuously increases for WMS and decreases for NRS with increase in sucrose concentration. The Gelatinization Temperature increases with increase in sucrose concentration for all starches. Enthalpy of Gelatinization increases with increase in sucrose concentration for Normal starches where as there is no effect of sucrose concentration for waxy starches. Flory Huggins starch-sucrose interaction parameter was characterized which is used to predict the equilibrium swelling power using a mathematical model proposed to quantitatively describe the equilibrium swelling in the presence of solute (sucrose) based on Flory Huggins polymer solution theory to develop rational guidelines for identification of sugar substitute with desirable functional properties. The model predictions of equilibrium swelling power agrees with experimental results.</div>

This Master‘s thesis is focused on the preparation of hydrogels based on a hydrophobic derivative of hyaluronic acid palmitoyl hyaluronan in presence of biosurfactant decyl glucoside’s micelles and micelles of surfactant triton X-100. For followed characterization were chosen rheological tests and infrared spectrometry. There was observed influence of preparation method, type and concentration of surfactant and presence of micelles on final features of the hydrogel. Moreover, an experimental test of swelling was performed with interesting results for future research.

V této závěrečné práci bylo popsáno časné reologické chování alkalicky aktivované strusky, anorganického materiálu, který vzniká aktivací mleté granulované vysokopecní strusky alkalickým roztokem. Vliv typu aktivačního roztoku (hydroxidů, křemičitanů a uhličitanů) a jeho koncentrace na časné reologické parametry byl zkoumán pomocí amplitudových oscilačních měření. Bylo pozorováno, že typ aktivátoru je hlavním faktorem ovlivňujícím reologické chování alkalicky aktivované strusky. Dále bylo pozorováno, že aktivátory na bázi draslíku vedou ke slabší struktuře (nižší mez kluzu, mez toku a nižší hodnoty viskoelastických modulů) oproti použití aktivátorů na bázi sodíku. To lze vysvětlit rozdíly ve velikosti alkalických iontů. Na rozdíl od ostatních aktivátorů křemičitany způsobovaly zvýšení ztrátového faktoru, přičemž vykazovaly spíše kapalné chování. Z výsledků vyplynulo, že většina aktivátorů má tzv. kritickou hodnotu koncentrace, po jejímž dosažení mají reologické vlastnosti vzorků tendenci se měnit s rostoucí koncentrací. Získané výsledky korelovaly s výstupy zeta potenciálu.

Surfactants and Thickeners are both additives used in fully-formulated waterborne coatings to provide colloidal stability, thickening, and other functionality. The behavior of each ingredient in a coating must be understood and controlled to maintain colloidal stability as well as balance other desired properties of the liquid coating and the dry paint film. In this work, quaternary systems of Water-Latex-Thickener-Surfactant were investigated to further the understanding of their behavior in coatings. The thickener used was a well characterized, hydrophobically-modified, ethoxylated urethane (HEUR) with two C18 terminal hydrophobes and 795 average repeat units of ethylene oxide as the hydrophilic spacer. Two latexes, a hydrophobic butyl acrylate/styrene and a hydrophilic butyl acrylate/methyl methacrylate, each containing a small amount of methacrylic acid monomer were used. Six different surfactants, three non-ionic and three-anionic, were used. By maintaining the concentrations of latex and HEUR thickener as constants and varying the surfactant concentration, effects of the surfactant loading on rheology were determined. As concentration of surfactant increases, a characteristic shear-thickening maximum associated with bridging of latex particles by the HEUR thickener was seen to shift to higher shear rates; surfactants at all concentrations studied, except SDS, lowered the viscosities within the low shear rate region. Dynamic viscoelastic measurements shed further light into the behavior of the mixtures. The results will be explained based on surfactant and latex surface polarities and the competitive adsorption between the v surfactant and HEUR hydrophobes, and other interactions between surfactants and thickeners.

The aim of this diploma thesis was create a natural BB cream that, in addition to sufficient hydration, would protect the skin from sunlight, unify its colour tone and at the same time sufficiently cover any imperfections. After proposition a suitable recipe, it was necessary to determine the stability of the prepared BB creams. The stability was evaluated by comparing the results from the dispersion analyser LUMiSizer at various temperatures and current load tests in an oven. The pseudoplastic properties were confirmed by the rheology characterization of the flow properties, which makes the BB cream a continuous layer on the skin after it is spread. In order to protect against sunlight, it was necessary to determine the SPF and measure the colour shades of the prepared BB creams for comparison with commercially available preparations.