Yes / There are many polymers formed of acrylate monomers in existence. Here we interrogate four commonly-used examples and study how their solution properties are pH dependent, or how their state of ionisation can affect their solution properties. Poly(acrylic acid) and poly(methacrylic acid) are both polyelectrolytes, with ionisable functional groups that make them stimuli responsive, changing their hydrodynamic volume. Poly(acrylamide) is a mass-produced material used in a variety of industrial applications, often with an anionic and cationic co-monomer, which dictates both its efficacy and impact on the environment. Poly(N-isopropyl acrylamide) is a thermally responsive material with applications in smart bioengineering. In solution, these materials can interact with each other due to competing hydrogen bonding interactions. However, this interpolymer complexation is dependent on both the ionisation, and the conformational state, of the polymers involved. This review focuses on the results from fluorescence tagging and turbidimetric techniques.

La complexation de l'arénophile à un ligand naphtalène substitué sur un seul noyau par un ou deux groupe triméthylsilyléthynyle conduit à la formation des deux régio-isomères A (arénophile coordiné au cycle substitué) et B (arénophile lié au cycle libre). L'isomère A est le produit cinétique et l'isomère B le produit thermodynamique de la réaction. La substitution du groupe trimétylsilyle par le fragment organométallique électro-actif permet d'étudier l'isomérisation A B . La migration haptotropique électro-induite, réalisée à 20 °C, est quasi quantitative . Elle résulte de l'activation de la liaison Ru provoquée par l'oxydation mono-électronique du centre redox organofer en présence d'un solvant coordinant . La synthèse du complexe ortho disubstitué, stériquement très encombré, et de ses dérivés mono- et di-oxydés a été effectuée avec succès. L'espèce mono-oxydée qui possède un couplage électronique fort est un dérivé à valence mixte de classe II B, à la limite entre les classes II et III. Les complexes tétranucléaires ont également été synthétisés et caractérisés par différentes techniques incluant notamment la radiocristallographie. Ces composés présentent des interactions électroniques à la fois en ortho, meta et para, générant de nouvelles propriétés qui pourraient s'avérer totalement inédites dans le domaine de l'électronique moléculaire. Finalement, une nouvelle famille de composés hybrides organiques inorganiques trans- a aussi été préparée (TTF = tétrathiafulvalène; n = 0-3). Le dérivé mono-oxydé est un composé à valence mixte de classe II. Le transfert d'électron intramoléculaire peut se faire selon un mécanisme par effet tunnel et par un mécanisme multi-étape par sauts entre les centres redox inorganiques et organiques. / The complexation of the arenophile to a naphthalene ligand bearing one or two trimethylsilylethynyle group gives the two regioisomers A (arenophile coordinated to the substituted ring) and B (arenophile coordinated to the free cycle). Isomer A is the kinetic product and isomer B is the thermodynamic product of the reaction. The substitution of the trimethylsilyl group by the electroactive organometallic fragment allows to control the isomerization from A to B. The electro induced haptotropic migration, performed at 20 ° C, is almost quantitative, and results from the activation of the Ru bond induced by the one-electron oxidation of the organoiron redox center in the presence of a coordinating solvent. The synthesis of the sterically constraint ortho disubstituted complex, and its mono and di-oxidized forms were successfully achieved. The mono-oxidized species that shows a strong electronic coupling is a Class-II B mixed valence compound. The tetranuclear complexes were also prepared and characterized by various methods including X-ray crystallography. These compounds exhibit electronic interactions in the ortho, meta and para positions, generating new properties that could be of great interest in the field of molecular electronics. Finally, a new family of organic-inorganic hybrids trans- has also been prepared (TTF = tetrathiafulvalene; n = 0-3). The mono-oxidized complex (n = 1) is a Class-II mixed-valence compound in which the spin density varies with the respective orientation of the metal termini. Intramolecular electron transfer occurs through single-step tunneling and multiple-step hopping mechanisms.

Στην εργασία αυτή προχωρήσαμε στη μελέτη της αλληλεπίδρασης των ιόντων δισθενούς χαλκού, Cu2+ με στατιστικά συμπολυμερή P(ANa-co-SSNa) του ακρυλικού οξέος, (ANa) με το στυρενοσουλφονικό οξύ (SSNa). Συντέθηκαν τα συμπολυμερή P(ANa50-co-SSNa) και P(AΝa80-co-SSNa) που περιέχουν 50 mol% και 80 mol% ακρυλικού οξέος αντίστοιχα. Τα συμπολυμερή αυτά χαρακτηρίστηκαν με φασματοσκοπία πυρηνικού μαγνητικού συντονισμού 1H NMR. Προχωρήσαμε στην φυσικοχημική μελέτη της αλληλεπίδρασης ιόντων δισθενούς χαλκού, Cu2+, με τα συμπολυμερή P(ANa50-co-SSNa) και P(AΝa80-co-SSNa) χρησιμοποιώντας διάφορες τεχνικές όπως η θολομετρία, η ιξωδομετρία και η φασματοσκοπία UV-vis. Τα πειράματα πραγματοποιήθηκαν σε υδατικά διαλύματα, στα οποία χρησιμοποιήθηκε ως διαλύτης τρισαπιονισμένο νερό, H2O-3D. Για λόγους σύγκρισης μελετήθηκαν επίσης τα αντίστοιχα ομοπολυμερή των μονομερών που αποτελούν τα συμπολυμερή P(ANa-co-SSNa). Έτσι, πραγματοποιήθηκε φυσικοχημική μελέτη της αλληλεπίδρασης των ιόντων Cu2+ με το πολυ(ακρυλικό νάτριο), PANa, και το πολυ(στυρενοσουλφονικό νάτριο), PSSNa, αντίστοιχα. Από την ιξωδομετρική μελέτη προέκυψε πως η εισαγωγή ιόντων χαλκού Cu2+ σε υδατικό διάλυμα πολυμερούς οδηγεί στην μείωση του ανηγμένου ιξώδους. Μάλιστα η μείωση αυτή είναι πιο δραστική καθώς αυξανεται η συγκέντρωση ιόντων Cu2+ στο διάλυμα. Αυτή η συμπεριφορά αποτελεί ένδειξη της συμπλοκοποίησης των ιόντων χαλκού, Cu2+, με τις ομάδες καρβοξυλίων του ακρυλικού οξέος (ΑΑ). Διαπιστώθηκε πως στα συμπολυμερή P(ANa-co-SSNa) τα Cu2+ συμπλοκοποιούνται με τα καρβοξύλια του ακρυλικού οξέος σε αναλογία ιόντων χαλκού προς ομάδες καρβοξυλίων ίση με 1:2. Όσον αφορά στην μελέτη με UV-vis, ενώ στην περίπτωση του ομοπολυμερούς PSSNa δεν υπάρχει κάποια ιδιαίτερη αλληλεπίδραση τύπου συμπλόκου ένταξης μεταξύ του πολυμερούς και των ιόντων του Cu2+, στην περίπτωση του συμπολυμερούς Ρ(ΑNa50-co-SSNa), παρατηρήθηκε μετατόπιση του σήματος των ιόντων Cu2+ (από τα 800 στα 745 nm) παρουσία του συμπολυμερούς. Αυτό είναι χαρακτηριστικό του σχηματισμού συμπλόκου ένταξης μεταξύ των ιόντων του Cu2+ και των ομάδων COO- του συμπολυμερούς. / In the present work we studied the interaction of bivalent copper ions Cu2+ with random copolymers P(ANa-co-SSNa) of acrylic acid (ANa) and styrenesulfonic acid (SSNa). Two copolymers, P(ANa50-co-SSNa) and P(AΝa80-co-SSNa) with 50 mol% and 80 mol% in acrylic acid, respectively, were synthesized and characterized by neutron magnetic resonance spectroscopy, 1H NMR. We proceeded in the physicochemical study of the interaction of bivalent copper ions, Cu2+, with P(ANa50-co-SSNa) and P(AΝa80-co-SSNa) copolymers using techniques like turbidimetry, viscometry and UV-vis spectroscopy. The experiments were performed in aqueous media using 3D water, H2O-3D. For reasons of comparison the respective homopolymers of sodium polyacrylate, PANa, and poly(styrene sulfonate), PSSNa, were also studied. From viscometry it was found that the introduction of copper ions in the polymer aqueous solutions leads to the decrease of the reduced viscosity. Moreover, this decrease is more pronounced as the concentration of Cu2+ increases in the solution. This behavior is indicative of the complexation between Cu2+ with the carboxylate groups of acrylic acid (ΑΑ). In the P(ANa-co-SSNa)/Cu2+ system, it was found that complexation occurs when the ratio of copper ions to carboxylates is equal to 1:2. UV-vis spectroscopy showed that, while in the case of PSSNa homopolymer there is not strong interaction with Cu2+, in the case of the Ρ(ΑNa50-co-SSNa) copolymer, the introduction of the polymer lead to a shift of the maximum absorbance of Cu2+ (from 800 to 745 nm). This was due to the complexation of Cu2+ with the COO- groups of the copolymer.

Les phénomènes d'adsorption interviennent dans les processus géochimiques gouvernant ainsi le transport des contaminants. Par ailleurs, les variations de température sont susceptibles d'influencer significativement leur comportement vis-à-vis de la surface des minéraux. Aussi, l'influence de la température sur la sorption doit être étudiée afin de mieux appréhender le devenir des éléments dans l'environnement. Dans cette optique, l'interaction entre un ion modèle, l'uranyle et deux minéraux a été étudiée. Dans un premier temps, un composé méthodologique, la monazite, a été choisi afin de déterminer la démarche à suivre pour étudier l'influence de la température sur la sorption de l'uranyle dans trois milieux plus ou moins complexants. Puis, des tests préliminaires ont été réalisés pour étudier la sorption de l'uranyle sur un composé d'intérêt industriel, la magnétite, en appliquant la démarche mise en place. Le solide a d'abord été caractérisé d'un point de vue massif puis les caractéristiques acido-basiques de sa mise en suspension dans les trois électrolytes (NaClO4, NaNO3 et Na2SO4) ont été étudiées en fonction de la température. Les constantes d'équilibre associées aux réactions de déprotonation des sites de surface ont été déterminées entre 25°C et 95°C par modélisation de courbes de titrages potentiométriques. Les simulations ont été effectuées en limitant au maximum le nombre de degrés de liberté du système. Le modèle 1-pK a donc été préféré au modèle 2-pK en raison du nombre de paramètres ajustables plus limité dans ce modèle. Des contraintes expérimentales telles que le pH de point de charge nulle ou les enthalpies déterminées par mesure directe des chaleurs associées par microcalorimétrie de mélange ont été imposées pour déterminer les constantes d'équilibre acido-basiques. La sorption de l'uranyle en fonction du pH sur le même intervalle de température a été étudiée en alliant l'acquisition de données macroscopiques telles que les sauts de sorption et la spéciation en solution à une étude structurale menée par analyse par spectrofluorimétrie laser permettant l'identification des espèces sorbées. La simulation des sauts de sorption permettant d'accéder aux constantes associées aux réactions de sorption a été réalisée en imposant les caractéristiques acido-basiques préalablement déterminées. Des mesures directes, par microcalorimétrie de mélange, des chaleurs mises en jeu lors de la sorption de l'uranyle ont permis de tester la validité de la loi de Van't Hoff sur ce phénomène. La même démarche a été suivie pour étudier l'influence de la température sur la sorption de l'uranyle sur la magnétite en milieu NaClO4 et NaNO3. Cependant, l'étude structurale par spectrofluorimétrie laser n'a pu être réalisée en raison de la couloration noire de la magnétite.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Les émulsions doubles de type eau-dans-huile-dans-eau (E/H/E) sont des systèmes dans lesquels des globules gras sont dispersés dans une phase continue aqueuse. De par leur structure compartimentée, ces systèmes permettent d’encapsuler des composés hydrosolubles au niveau des gouttelettes aqueuses internes. Néanmoins, leur utilisation requiert la maîtrise de leur stabilité thermodynamique et la compréhension des mécanismes mis en jeu au cours de la libération des espèces encapsulées. C’est dans ce contexte que différents paramètres de formulation, i.e., nature de l’huile, concentration en émulsifiant hydrophile, fraction volumique en globules gras, complexation de l’espèce encapsulée ont été testés de manière à appréhender leur influence sur la libération des ions magnésium. Les constituants utilisés pour la préparation des émulsions E/H/E sont de grade alimentaire en vue de leur application dans les secteurs pharmaceutique ou alimentaire. La fuite des ions magnésium s’effectue essentiellement par un mécanisme de diffusion/perméation. Un modèle basé sur la diffusion du magnésium à travers la phase huileuse a été proposé, prenant en compte le coefficient de perméation de l’espèce ionique, la chélation du magnésium et l’ajustement des pressions osmotiques entre les phases interne et externe. Ainsi, le coefficient de permétation dépend de la localisation et de la concentration du chélatant, mais n’est que faiblement influencé par la pression osmotique. De plus, ce coefficient évolue au cours du temps notamment pour les fractions volumiques en globules gras élevés. / Double water-in-oil-in-water (W/O/W) emulsions are systems in which fat globules are dispersed in an aqueous continuous phase. They provide a compartmented structure that allows the encapsulation of hydrosoluble compounds in the internal aqueous droplets. Nevertheless, the application of multiple emulsions is limited by their thermodynamical instability and the possible diffusion of hydrosoluble matter from one aqueous phase to the other one through the oil layer. In this context, the influence of several formulation parameters (oil nature, hydrophilic emulsifier concentration, oil globule mass fraction, complexation of the encapsulated species) was investigated relatively to magnesium release. All the ingredients used were food grade to match pharmaceutical and food application requirements. Magnesium leakage occurred without film rupturing. A model based on diffusion was proposed in which the rate of release was determined by the permeation coefficient of magnesium across the oil phase, by magnesium chelation and by the osmotic pressure mismatch between the internal and external aqueous phases. The permeation coefficient depended on the chelating agent location and concentration but was poorly influenced by the osmotic pressure. Moreover, the permeation coefficient evolved with time, especially at high oil globule fractions.

Estudou-se a adsorção de Cd(II) e Pb(II) em uma suspensão de vermiculita 1,0 g L-1 em meio de KNO3 2 e 20 mmoI L-1 em pH 5,0; 6,0 e 7,0 (±0,1). Após um tempo de equilíbrio de 6 h, as suspensões foram centrifugadas e o sobrenadante analisado por voltametria de redissolução anódica em condições de fluxo contínuo na etapa de acumulação. A capacidade de adsorção e afinidade das ligações, avaliadas pelos métodos de Scatchard e Freundlich, foi maior para o Pb(II) do que para o Cd(II), aumentando para ambos os cátions com o aumento do pH e diminuição da força iônica. De modo geral, a incorporação de substância húmica na vermiculita, obtida a partir de uma suspensão 30 mg L-1 de ácido húmico (AH), aumentou a capacidade de adsorção de Pb(II) e Cd(II) nas condições estudadas. Em uma segunda etapa estudou-se a adsorção do herbicida atrazina (AT) e os metabólitos hidróxi-atrazina (HAT), desetil-atrazina (DEA) e desisopropil-atrazina (DIA) em amostra de solo. O estudo foi conduzido em suspensão contendo 1,0 g de solo e 5 mL de solução de CaCI2 0,01 moI L-1 em pH 5,2 ± 0,1, contendo o herbicida e os metabólitos. Após um tempo de equilíbrio de 24 h, as suspensões foram centrifugadas e as soluções analisadas por HPLC. O tratamento de dados pelos métodos de Scatchard e Freundlich revelou a ordem de afinidade e capacidade de adsorção: HAT > AT > DEA =~ DIA, tanto na presença, como na ausência de AH. / The adsorption of Cd(lI) and Pb(lI) was studied in a 1,00 g I-1 vermiculite suspension in 2 and 20 mmol I-1 KNO3 medium at pH 5,0; 6,0 and 7,0 (±0,1). After 6 h of equilibrium time, the suspensions were centrifuged and the supernatants analyzed by anodic stripping voltammetry under continuous flow in the accumulation step. To evaluate the adsorption capacity and the binding affinity, the Scatchard and Freundlich methods were employed, showing a greater removal process for Pb(II), increasing for both ions at higher pH values and smaller ionic strength. In short, the vermiculite treated with a 30 mg I-1 humic acid (HA) suspension showed an enhancement of the adsorption capacity for Cd(lI) and Pb(lI) under alI conditions of this study. Secondly, the adsorption process of the herbicide atrazine (AT), and the metabolites hidroxyatrazine (HAT), deethylatrazine (DEA) and deisopropylatrazine (DIA) was studied in a soil sample. The study was carried out in a 5 ml suspension with 1,0 g of soil in 0,01 moI I-1 CaCl2 solution, pH 5.2 ± 0.1, in the presence of the herbicide and metabolites. After an equiIibrium time of 24 h, the suspensions were centrifuged and the supernatants analyzed using HPLC. The data treatment using Scatchard and Freundlich methods revealed the following adsorption capacity and affinity order: HAT > AT > DEA =~DIA, in the presence or absence of HA.

O galato de lantânio contendo substituições parciais de estrôncio e magnésio (La1-xSrxGa1-yMgyO3-δ) apresenta estrutura tipo perovsquita e alta condutividade para íons de oxigênio. Outras características desta cerâmica são o extenso domínio eletrolítico e a baixa condutividade eletrônica. É um material promissor para uso como eletrólito sólido em células a combustível de óxido sólido que operam em temperaturas intermediárias, devido sua alta condutividade iônica e estabilidade em uma ampla faixa de pressão parcial de oxigênio. Neste trabalho, a composição La0,9Sr0,1Ga0,8Mg0,2O3-δ foi preparada pelo método convencional de mistura de óxidos a partir de diferentes rotas e pelo método de complexação de cátions. As amostras foram consolidadas pelo método convencional de sinterização e por sinterização rápida. Pelo método de mistura de óxidos foi possível obter a fase ortorrômbica do LSGM, mas não foi possível eliminar as fases SrLaGaO4, La4Ga2O9 e SrLaGa3O7, independente das condições de sinterização utilizadas. Precipitados de óxido de magnésio foram observados nas amostras preparadas pelos dois métodos de síntese empregados identificados apenas por microscopia eletrônica de varredura. As densidades obtidas foram superiores a 97% da densidade teórica em amostras sinterizadas a 1450 °C/4 h, para os materiais preparados por mistura de óxidos. Amostras preparadas por método de complexação de cátions e aquelas consolidadas por sinterização rápida apresentaram menores valores de densidade. Grãos de tamanhos micrométricos foram obtidos para os dois métodos de sinterização. Amostras calcinadas a 1250°C apresentaram maiores densidades e maiores valores de condutividade iônica dos grãos e dos contornos de grãos, quando comparadas com as demais amostras. / Lanthanum gallate with partial substitution on La and Ga sites (La1-xSrxGa1-yMgyO3-δ) has perovskite structure and high oxide-ion conductivity. Other properties of this ceramic material comprise a relatively wide electrolytic domain and low electron conductivity. Doped lanthanum gallate is a potential solid electrolyte for intermediate-temperature solid oxide fuel cells due to its high ionic conductivity and stability in a wide range of oxygen partial pressure. In this work, the composition La0.9Sr0.1Ga0.8Mg0.2O3-δ was prepared by the conventional method of mixing of the starting oxides followed by different processing routes and by the cation complexation method. The ceramic specimens were consolidated by conventional sintering and by fast firing. All specimens prepared by solid state reaction show the characteristic orthorhombic phase of lanthanum gallate and SrLaGaO4, La4Ga2O9 and SrLaGa3O7 secondary phases, independent on the method of sintering. Energy dispersive X-ray spectroscopy coupled to scanning electron microscopy evidenced that all prepared specimens contain MgO grains precipitated along the grain boundaries. High relative densities were obtained for specimens prepared by solid state reaction and consolidated by conventional sintering at 1450 °C/4 h. All specimens exhibit micron sized grains independent on the sintering method. The highest values of relative density and ionic conductivity were obtained for specimens calcined at 1250°C.

A estrutura e o comportamento de proteínas são de grande interesse a uma infinidade de áreas de conhecimento, com especial destaque para alimentação e saúde. As proteínas compõem uma fundamental classe de moléculas biológicas, com capacidade para interagir com diversas outras estruturas e formar complexos. Dois tópicos principais são abordados neste trabalho: (a) avaliação da formação de complexos entre três proteínas do soro do leite (-lactoalbumina, -lactoglobulina e lactoferrina) em diferentes condições experimentais de força iônica e pH da solução através de derivadas da energia livre e (b) avaliação de aspectos relacionados com a fundamentação teórica dos modelos moleculares com granularidade grossa e uso do dielétrico contínuo empregados para estudo do fenômeno da complexação molecular, através da análise, em larga escala, da correlação de cargas em proteínas disponíveis no banco de dados de proteínas. Os estudos teóricos de complexação foram realizados através do emprego de simulações Monte Carlo Metropolis, com o modelo do solvente contínuo, constante dielétrica homogênea e sal implicitamente descrito. Os estudos de complexação permitem compreender os mecanismos moleculares envolvidos, elucidando, inclusive, controvérsias experimentais e oferecendo orientação para aplicações. Já os resultados do estudo de correlação de cargas em estruturas experimentais de proteínas permitem justificar as aproximações do modelo. / The structure and behavior of proteins are of great interest for a number of science fields, with special emphasis to food industry and health. Proteins comprise a fundamental group of biological molecules, with the capacity of interacting with several other structures and creating complexes. Two major topics are covered in this study: (a) evaluation of complex formation among three whey proteins (-lactalbumin, -lactoglobulin and lactoferrin) under different experimental conditions of ionic strength and pH of solution through free energy derivatives and (b) evaluation of features related to the theoretical basis of the coarse-grained molecular models and the use of continuous dielectric which are employed to investigate the molecular complexation phenomenon, through analysis, on a large scale, of charge correlation in proteins available in the protein data bank. The theoretical studies of complexation were performed through the use of Monte Carlo Metropolis simulations, with continuous solvent model, homogeneous dielectric constant and salt implicitly described. The complexation studies allow to understand the molecular mechanisms involved, also elucidating experimental controversies and offering orientation to applications; whereas the results of the charge correlation study in experimental structure of proteins allow justify the approximations of the model.