The goal of service life prediction is to accurately predict the useful lifetime of a coating system in a typical service environment. Field testing is the most true-to-life form of service life testing but requires long exposure times, often not quick enough to readily aid redesign in the product development cycle. As an alternative, accelerated weathering chambers are used to speed up coating failure in a laboratory setting. These devices do indeed accelerate failure but often produce failure modes that are not seen in actual service or produce material rankings that are not reproducible. This work explores the principle of cumulative stressor damage for an exterior architectural coating being exposed to outdoor conditions in San Luis Obispo, California, as well as an accelerated UV/moisture protocol. The accelerated UV/moisture protocol is executed first by ASTM D4587, and then by creating a custom exposure test cycle based on locally observed weather. Comparison of failure mode and quantification of failure is determined by gloss and spectral reflectance measurements. Finally, acceleration factor determination for the new SLO-in-a-box protocol is outlined, with a discussion of preliminary results.

Le caoutchouc naturel produit du latex d'Hevea brasiliensis a des propriétés remarquables qui n'ont jamais été égalées par ses homologues synthétiques. Toutefois, ce matériau d'origine naturel présente un désavantage : la variabilité non négligeable de ses propriétés. Cette dernière est partiellement attribuée aux 3 à 5 % de composés non isoprènes (lipides, protéines, sucres et minéraux) présents dans le caoutchouc naturel. Parmi les facteurs pouvant être tenus comme responsables de cette variabilité, l'origine clonale semble prépondérante. L'objectif principal de cette étude était d'évaluer l'impact de l'origine clonale sur la variabilité en composition biochimique du latex (lipides, protéines, sucres et éléments minéraux) et sur les caractéristiques mésostructurales du caoutchouc naturel; puis d'étudier les relations pouvant exister entre le génotype, la composition biochimique du latex et la mésostructure du caoutchouc. Cette étude a été conduite sur 5 clones d'Hevea brasiliensis : GT1, RRIM600, PB235, PB217 et PB260. Des études préalables à la caractérisation clonale ont permis de déterminer les conditions d'échantillonnage à mettre en œuvre pour pratiquer des prélèvements de latex clonaux les plus représentatifs possible des clones. Le latex étant un matériau instable, il été choisi de travailler sur du latex lyophilisé pour l'analyse de tous les composés biochimiques du latex (autres que les lipides) et pour l'étude de la mésostructure du caoutchouc naturel. Des protocoles d'extractions des protéines et des sucres sur lyophilisat de latex ont été développés en se basant sur les propriétés de solubilisation du caoutchouc naturel en milieu organique. L'extraction des lipides a été réalisée en suivant le protocole mis au point sur plantation sur latex frais par Liengrayoon (Liengprayoon, 2008). Les différents résultats obtenus au niveau de la composition biochimique du latex et de la mésostructure du caoutchouc ont permis de mettre en évidence l'importante de l'origine clonale des latex. L'étude des relations entre le génotype et la composition biochimique du latex (ACP) a clairement montré que l'origine clonale jouait un rôle important dans la variabilité totale des données biochimiques du latex. Les analyses des relations entre la biochimie du latex et la mésostructure du caoutchouc naturel ont permis de mettre en évidence des corrélations intéressantes des lipides et des protéines avec la mésostructure (essentiellement Mn et I). Cette analyse biochimique clonale des latex s'est révélée pertinente pour étudier la diversité clonale et ses répercutions sur la mésostructure du caoutchouc naturel. Cette approche de la diversité clonale d'Hevea brasiliensis, ainsi que les connaissances acquises lors de cette étude constituent une base de données solide à compléter par des études futures sur des plantations différentes, des clones différents et des analyses biochimiques et structurales plus poussées. / Natural rubber produced from Hevea brasiliensis latex possesses remarkable properties which have not been matched by its synthetic counterparts. However, this natural origin material presents a disadvantage: the significant variability of its properties. This variability has been partly ascribed to the 3 to 5% non isoprene components (lipids, proteins, sugars and minerals) present in the natural rubber. Among the factors that could be held responsible for this variability, clonal origin seems to be decisive.The main aim of this study was to evaluate the impact of clonal origin on the biochemical latex composition and on natural rubber mésostructural characteristics and also to study relationships between genotype, latex biochemical composition and rubber mesostructure. This study was conducted with five Hevea brasiliensis clones: GT1, RRIM600, PB235, PB217 and PB260. Before clonal characterization, preliminary studies were performed to determine the suitable sampling conditions in order to get the latex samples that represented as much as possible the clones. Fresh latex is an unstable material. It was decided to work on freeze-dried latex for the biochemical components analysis (except lipids) and for the natural rubber mesostructure study. Protocols for proteins and sugars' extractions on freeze-dried latex have been developed on the natural rubber solubilizing properties in organic media. Lipids extractions was performed according to the protocol developed by Liengrayoon (Liengprayoon , 2008) on fresh latex.The different results obtained on the latex biochemical composition and the natural rubber mesostructure allowed to clearly observe the clonal origin importance. Study of relationships between genotype and latex biochemical composition (PCA) has clearly shown that the clonal origin played an important role in the total variability of latex biochemical data. Analysis of relationships between latex biochemistry and natural rubber mesostructure helped highlight interesting correlations of lipids and proteins with mesostructure (mainly Mn and I).This biochemical analysis of clonal latex has proved to be appropriate for studying the clonal diversity and its repercussions on the natural rubber mesostructure. This approach of Hevea brasiliensis clonal diversity, and the knowledge gained from this study, provides a solid basis to be completed by further studies on different plantations, different clones and further biochemical and structural analyses.

Latex d’Hevea brasiliensis est composé principalement de particules de caoutchouc dont le noyau est constitué de cis-1,4-polyisoprène et la membrane de composés dit non-isoprène. Sa stabilité dans l'arbre est assurée par les charges négatives de la membrane en raison de la présence de protéines et de lipides. Le latex d’Hevea brasiliensis coagule après acidification pour former un gel colloïdal qui est la première étape de sa transformation en caoutchouc naturel.Dans cette thèse, nous avons étudié l’agrégation et la gélification induite par ajout d’un acide et les propriétés des gels obtenus. Pour cela, un latex de caoutchouc naturel commercial constitué par des particules de caoutchouc (1 µm de diamètre), a été utilisée. L'agrégation a été induite par l'hydrolyse d'un composé appelé glucano-delta-lactone (GDL). Cette agrégation a été suivie par différentes techniques basées sur la diffusion de la lumière (turbidimétrie, DWS, SLS). La gélification a été suivie in situ par la rhéologie. Ensuite, les propriétés rhéologiques de gels colloïdaux formés à pH 4 ont été caractérisées dans les régimes linéaires et non-linéaires.La dépendance à la fraction volumique et le pH de l'apparition de l'agrégation ont été observée. La non-redispersion des agrégats montre les interactions fortes entre les particules de caoutchouc. Trois comportements d’état différents (solution stable, la séparation de phase et gel) peuvent être prédits à partir d'un diagramme d’état fraction volumique-pH qui a été établi pendant 5 semaines. L'état de gel présente une structure fractale, caractérisé par une relation de loi de puissance entre le module élastique G' et la fraction volumique. Pour des fortes déformations, une réorganisation irréversible sous contrainte a abouti à un durcissement irréversible du matériau. Nous avons observé par rheo-ultrasound qu'au-dessus de 50% de déformation, une déstructuration homogène est produite dans le gel. / Natural rubber latex is mainly composed by rubber particles whose core is made of cis-1,4-polyisoprene and the shell of non-isoprene compounds. It stability in the tree is provided by the negative charge of the shell due to the presence of proteins and lipids. Natural rubber latex coagulates after acidification to form a colloidal gel that is the first step of its transformation into natural rubber.In this PhD thesis, we studied this acid-induced aggregation and gelation and the properties of the resulting gels. For this, a commercial natural rubber latex composed by rubber particles (1 µm in diameter), was used. Aggregation was induced by hydrolysis of a compound called glucano-delta-lactone (GDL). The aggregation was followed by different techniques based on light scattering (turbidimetry, DWS, SLS). Gelation was followed in situ by rheology. Then, the rheological properties of colloidal gels formed at pH 4 were characterized in the linear and non-linear regimes.Dependence to the volume fraction and the pH of the onset of aggregation was observed. The non-redispersion of aggregates proves the strong interactions between rubber particles. Three different state behaviors (stable solution, phase separation and gel) can be predicted from a state diagram pH-volume fraction that was established over 5 weeks. The gel state exhibits a fractal structure, characterized by a power law relationship between the elastic modulus G’ and the volume fraction. At high deformations, an irreversible reorganization under stress resulted in an irreversible strain hardening of the material. We observed by rheo-ultrasound that above 50% deformation, an homogenous destructuration occurred in the gel.

Ao pensarmos no Ensino de Física voltado aos alunos com deficiência visual, a linguagem matemática mostra-se desafiadora, pois sua sintaxe bidimensional, essencialmente simbólica, restringe-a a uma \"cultura de videntes\". Com o desenvolvimento dos ledores de tela, tornou-se possível o acesso ao computador por pessoas com deficiência visual. No entanto a linguagem matemática convencional oferece certas barreiras à acessibilidade. O problema central de nossa investigação foi: Quais as possibilidades e limitações ao se introduzir a linguagem LaTeX, associada à softwares ledores de tela, na mediação de processos ativos de leitura e resolução de problemas de Física, por meio do computador, que envolvam expressões matemáticas? Segundo Vigotski, a mediação simbólica é o pilar central da relação do homem com o meio ambiente e com próprio homem, por meio da qual as funções psicológicas superiores se desenvolvem. Vigotski caracteriza o processo de mediação por meio de dois elementos: O instrumento, que regula as ações sobre os objetos, e o signo, que regula as ações sobre o intelecto das pessoas. O trabalho foi estruturado sob as bases da pesquisa qualitativa, sendo a interpretação dos dados baseada na Análise do Discurso em Bakhtin. Para Bakhtin, o processo da comunicação passa pela \"compreensão\" e posteriormente pela \"resposta\", cujos interlocutores saem da condição de somente ouvintes e passam a ter uma atitude \"responsiva ativa\", devendo considerar como \"unidade real da comunicação verbal\", não a palavra, mas o \"enunciado\". Para a primeira etapa, em que submetemos quatro softwares ledores de tela (NVDA, ORCA, JAWS e VIRTUAL VISION) à leitura de sentenças matemáticas presentes em textos de Física, os resultados mostraram que as principais barreiras à acessibilidade estavam concentradas em elementos gráficos e na linguagem matemática. Ao testarmos a acessibilidade dos ledores de tela com expressões matemáticas baseada no padrão QWERTY, o resultado foi a leitura integral de cada caractere por parte deles. Assim, o problema central da acessibilidade a conteúdos matemáticos presentes em textos de Física, não estava nos ledores de tela, mas na própria linguagem matemática. O objetivo foi chamar a atenção para uma linguagem de programação bastante difundida no meio acadêmico, principalmente na Física e Matemática, a Linguagem LaTeX, na diminuição de barreiras no uso do computador por alunos com deficiência visual em aulas de Física. Na segunda etapa, em que introduzimos a Linguagem LaTeX no contexto do processo ativo de leitura e resolução de problemas de Física por dois alunos do ensino médio de uma escola pública, a nova linguagem não somente mostrou-se acessível como compreensível por parte deles. Assim, destacamos como potencialidades da linguagem LaTeX: Compor-se de caracteres textuais, acessíveis aos dispositivos OCR; Possuir padrão de escrita linear, portanto simplificado; Possuir códigos curtos e intuitivos, facilitando sua memorização e utilização. Em se tratando de uma linguagem padronizada, suas limitações estavam relacionadas à sua estrutura, ou seja, o fato de os códigos serem escritos em Inglês e as expressões matemáticas escritas dentro de ambientes matemáticos, o que dificulta o processo de interiorização e aplicação dessa nova linguagem por parte dos alunos. / When we think about the Physics Teaching facing students with visual impairments, the mathematical language show it challenging because its twodimensional syntax, essentially symbolic, it\'s restricted to a \"sighted people culture\". With the development of screen readers, it became possible computer access by people with visual impairments. However the conventional mathematical language offers certain barriers to accessibility. The central problem of our research was: What are the possibilities and limitations to introduce the LaTeX language associated with screen reader softwares, in the mediation of active processes of reading and solving physics problems, via computer, involving mathematical expressions? According to Vygotsky, the symbolic mediation is the central pillar of human\'s relationship with the environment and human himself, through which the higher mental functions develop. Vygotsky characterizes the mediation process by means of two elements: The instrument, which regulates the actions on objects, and the sign, which regulates the actions of the people intellect. The work was structured under the qualitative research basis, with data interpretation based on the discourse analysis on Bakhtin. For Bakhtin, the communication process involves the \"understanding\" and later the \"answer\", whose interlocutors leave the condition of hearers only and he starts to have an \"active responsive\" attitude and should be considered as \"real unity of verbal communication,\" not the word, but the \"enunciation\". For the first step, when we submit four screen readers software (NVDA, ORCA, JAWS and VIRTUAL VISION) the reading of mathematical sentences inserted in physics texts, the results showed that the main barriers to accessibility were concentrated in graphics and mathematics language. In testing the accessibility of screen readers with mathematical expressions based on the standard QWERTY, the result was the complete reading of each character from them. Thus, the central problem of accessibility to mathematical contents in physics texts, was not in the screen readers, but in the mathematical language. The objective was to attract attention to a widespread programming language in academia, especially in physics and mathematics, the LaTeX language, to reduce the barriers to computer use by students with visual impairment in Physics classes. In the second stage, when we introduce the LaTeX language in the context of the active process of reading and solving physics problems by two high school students from a public school, the new language not only proved to be accessible as understandable by them. Thus, we highlight as potential of LaTeX language: it\'s composed of textual characters, accessible to OCR devices; Owning linear writing standard, thus simplified; Have shorter and intuitive codes, making it easy to memorize and use. In the case of a standardized language, its limitations were related to its structure, for example, the fact that the codes were written in English and mathematical expressions written in mathematical environments, which complicates the process of internalization and application of this new language by the students.

Ao pensarmos no Ensino de Física voltado aos alunos com deficiência visual, a linguagem matemática mostra-se desafiadora, pois sua sintaxe bidimensional, essencialmente simbólica, restringe-a a uma \"cultura de videntes\". Com o desenvolvimento dos ledores de tela, tornou-se possível o acesso ao computador por pessoas com deficiência visual. No entanto a linguagem matemática convencional oferece certas barreiras à acessibilidade. O problema central de nossa investigação foi: Quais as possibilidades e limitações ao se introduzir a linguagem LaTeX, associada à softwares ledores de tela, na mediação de processos ativos de leitura e resolução de problemas de Física, por meio do computador, que envolvam expressões matemáticas? Segundo Vigotski, a mediação simbólica é o pilar central da relação do homem com o meio ambiente e com próprio homem, por meio da qual as funções psicológicas superiores se desenvolvem. Vigotski caracteriza o processo de mediação por meio de dois elementos: O instrumento, que regula as ações sobre os objetos, e o signo, que regula as ações sobre o intelecto das pessoas. O trabalho foi estruturado sob as bases da pesquisa qualitativa, sendo a interpretação dos dados baseada na Análise do Discurso em Bakhtin. Para Bakhtin, o processo da comunicação passa pela \"compreensão\" e posteriormente pela \"resposta\", cujos interlocutores saem da condição de somente ouvintes e passam a ter uma atitude \"responsiva ativa\", devendo considerar como \"unidade real da comunicação verbal\", não a palavra, mas o \"enunciado\". Para a primeira etapa, em que submetemos quatro softwares ledores de tela (NVDA, ORCA, JAWS e VIRTUAL VISION) à leitura de sentenças matemáticas presentes em textos de Física, os resultados mostraram que as principais barreiras à acessibilidade estavam concentradas em elementos gráficos e na linguagem matemática. Ao testarmos a acessibilidade dos ledores de tela com expressões matemáticas baseada no padrão QWERTY, o resultado foi a leitura integral de cada caractere por parte deles. Assim, o problema central da acessibilidade a conteúdos matemáticos presentes em textos de Física, não estava nos ledores de tela, mas na própria linguagem matemática. O objetivo foi chamar a atenção para uma linguagem de programação bastante difundida no meio acadêmico, principalmente na Física e Matemática, a Linguagem LaTeX, na diminuição de barreiras no uso do computador por alunos com deficiência visual em aulas de Física. Na segunda etapa, em que introduzimos a Linguagem LaTeX no contexto do processo ativo de leitura e resolução de problemas de Física por dois alunos do ensino médio de uma escola pública, a nova linguagem não somente mostrou-se acessível como compreensível por parte deles. Assim, destacamos como potencialidades da linguagem LaTeX: Compor-se de caracteres textuais, acessíveis aos dispositivos OCR; Possuir padrão de escrita linear, portanto simplificado; Possuir códigos curtos e intuitivos, facilitando sua memorização e utilização. Em se tratando de uma linguagem padronizada, suas limitações estavam relacionadas à sua estrutura, ou seja, o fato de os códigos serem escritos em Inglês e as expressões matemáticas escritas dentro de ambientes matemáticos, o que dificulta o processo de interiorização e aplicação dessa nova linguagem por parte dos alunos. / When we think about the Physics Teaching facing students with visual impairments, the mathematical language show it challenging because its twodimensional syntax, essentially symbolic, it\'s restricted to a \"sighted people culture\". With the development of screen readers, it became possible computer access by people with visual impairments. However the conventional mathematical language offers certain barriers to accessibility. The central problem of our research was: What are the possibilities and limitations to introduce the LaTeX language associated with screen reader softwares, in the mediation of active processes of reading and solving physics problems, via computer, involving mathematical expressions? According to Vygotsky, the symbolic mediation is the central pillar of human\'s relationship with the environment and human himself, through which the higher mental functions develop. Vygotsky characterizes the mediation process by means of two elements: The instrument, which regulates the actions on objects, and the sign, which regulates the actions of the people intellect. The work was structured under the qualitative research basis, with data interpretation based on the discourse analysis on Bakhtin. For Bakhtin, the communication process involves the \"understanding\" and later the \"answer\", whose interlocutors leave the condition of hearers only and he starts to have an \"active responsive\" attitude and should be considered as \"real unity of verbal communication,\" not the word, but the \"enunciation\". For the first step, when we submit four screen readers software (NVDA, ORCA, JAWS and VIRTUAL VISION) the reading of mathematical sentences inserted in physics texts, the results showed that the main barriers to accessibility were concentrated in graphics and mathematics language. In testing the accessibility of screen readers with mathematical expressions based on the standard QWERTY, the result was the complete reading of each character from them. Thus, the central problem of accessibility to mathematical contents in physics texts, was not in the screen readers, but in the mathematical language. The objective was to attract attention to a widespread programming language in academia, especially in physics and mathematics, the LaTeX language, to reduce the barriers to computer use by students with visual impairment in Physics classes. In the second stage, when we introduce the LaTeX language in the context of the active process of reading and solving physics problems by two high school students from a public school, the new language not only proved to be accessible as understandable by them. Thus, we highlight as potential of LaTeX language: it\'s composed of textual characters, accessible to OCR devices; Owning linear writing standard, thus simplified; Have shorter and intuitive codes, making it easy to memorize and use. In the case of a standardized language, its limitations were related to its structure, for example, the fact that the codes were written in English and mathematical expressions written in mathematical environments, which complicates the process of internalization and application of this new language by the students.

Rubber tree is one of the main plants which play an important role in the economy of Southeastern region, Vietnam. Approximately 90% of Vietnamese natural rubber latex is exported as raw products. The preliminary process of natural rubber latex discharges a large amount of wastewater to the environment. In Vietnam, there are many available technologies set up and operated for treatment wastewater of rubber latex processing. However, the effluent quality is still poor and the concentration of pollutants is higher than the required national technical regulation on the effluent of the natural rubber processing industry (QCVN 01:2008/BTNMT). Thus, this paper summarizes various technologies and methods currently applied for the treatment of latex processing wastewater in Vietnam. Additionally, the new effective methods being researched and applied in Thailand and Malaysia are also mentioned (countries with the highest production of natural rubber in the world). This paper also provides a screening of treatment technologies for reducing environmental pollution and contributing to high-quality effluent for meeting the required standard. / Cao su là một trong những cây trồng chính và đóng vai trò quan trọng trong nền kinh tế của miền Đông Nam Bộ, Việt Nam. Sản phẩm từ cây cao su thiên nhiên tại Việt Nam chủ yếu là xuất khẩu (khoảng 90%), tuy nhiên chỉ mới là dạng cao su thiên nhiên sơ chế. Quá trình sơ chế mủ cao su thiên nhiên thải bỏ một lượng lớn nước thải vào môi trường. Ở Việt Nam, hiện tại có rất nhiều công nghệ xử lý nước thải sơ chế mủ cao su đã được thiết lập và vận hành. Tuy nhiên, nồng độ ô nhiễm trong nước thải sau quá trình xử lý còn cao so với tiêu chuẩn yêu cầu (QCVN 01:2008/BTNMT). Vì vậy, bài báo này tóm tắt những công nghệ và phương pháp khác nhau được sử dụng để xử lý nước thải sơ chế mủ cao su tại Việt Nam gần đây. Thêm vào đó, những phương pháp mới và hiệu quả đang được nghiên cứu và áp dụng tại Malaysia và Thái Lan, những quốc gia có sản lượng sản xuất mủ cao su cao nhất trên thế giới cũng được giới thiệu. Bài báo này cũng cung cấp sự đa dạng của những phương pháp xử lý nhằm giảm thiểu ô nhiễm môi trường và góp phần đảm bảo chất lượng nước đầu ra đạt tiêu chuẩn cho phép.

Le séchage d’une solution chargée en particules est la solution la plus simple pour couvrir uniformément la surface d’un matériau. Le choix de la solution et ses propriétés physico-chimiques dictent alors le comportement du film obtenu. Le matériau peut ainsi être rendu hydrophobe en appliquant un tapis de molécules qui n’ont aucune affinité avec l’eau. Un moyen d’améliorer encore cette hydrophobie est de modeler la surface pour incorporer une certaine rugosité dans le revêtement. Cette stratégie est adoptée par plusieurs végétaux, dont le plus célèbre est le lotus.L’évaporation de suspensions apparait comme la méthode la plus simple pour parvenir à la structuration de la surface des matériaux. L’exemple le plus éloquent est celui de la goutte de café, où les particules viennent préférentiellement s’agglomérer sur son périmètre, portées par les différents flux résultant du mécanisme de séchage. Cependant, ce procédé d’auto-assemblage des particules sur la ligne triple air-liquide-substrat au cours du séchage, est difficile à appréhender. Ce constat est lié à la synergie entre la rhéologie des suspensions, leur physico-chimie et les aspects de tension inter faciale, qui s’opère au cours du procédé d’évaporation.Le travail proposé ici vise à comprendre et à maitriser le déplacement de la ligne triple pour accroitre le potentiel de cette méthode d’élaboration de revêtements. Nous proposons une méthode qui permet d’agir sur cette ligne triple. A la sortie de notre dispositif, le liquide est soumis à une évaporation libre, si bien que la ligne de contact adopte un mouvement périodique, apparenté à une respiration. Ce phénomène, peut être contrôlé en amplitude et en fréquence. Par la combinaison de paramètres mécaniques propres au procédé et d’autres intrinsèque au fluide, l’expérimentateur est capable de gouverner ce mouvement, ainsi que le profil du ménisque formé.La connaissance des moyens d’actions sur la respiration de la ligne triple est ensuite utilisée pour produire des surfaces périodiques. Ces dernières sont issues du séchage de latex de polymère. Le comportement cyclique de la ligne triple, combiné avec un déplacement contrôlé du substrat, permet de créer des zones préférentielles de dépôt. Les surfaces obtenues présentent un réseau de lignes successives, dont la longueur d’onde se rapporte aux paramètres du procédé. / Solvent evaporation appears as an easy way to deposit a periodic film on any surface. Its resulting structure is directly linked to the particles contained on the suspension and its behaviour with its solid and liquid environment during drying step. The coffee ring effect is the most eloquent example, which is characterized by a preferential agglomeration of the particle in the drop periphery. Such process is difficult to assess: handling the air-liquid-substrate interface movement is a basic need to increase the technical power of that coating method.To investigate the contact line motion during drying, we focus on the meniscus, which comes from a liquid flow between a sealed container and a substrate. Observations of liquid flowing out such disposal show a cyclic movement. Such phenomenon can be compared to a breathing of the contact line. The present work is firstly dedicated to the characterization of that periodic movement. These learnings are then applied to polymer latexes to produce periodic films.Our characterization method is based on meniscus observation and force balance recording. The observed breathing can be tuned in frequency and amplitude, by acting both on physical properties of the solvents, and geometrical settings of the device. Surface tension play a key role in the movement, by acting on the meniscus shape. Geometrical settings appears to affect the evaporation process. On a global scale, the rate is constant but the disposal gap is directly linked to the cycle frequency.Eventually, our disposal is used to coat smooth surface with polymer latexes. The self-organization of particles during the drying process is tried to be controlled by the periodic motion of the contact line. The roughness of the obtained textured coating is expected to be tuned by a combined choice of disposal settings and specific solutions properties.

Ce travail de thèse traite de l’élaboration de nanoparticules luminescentes à based’organolanthanides pour des applications d’imagerie biomédicale ou de marquage pour la lutte anticontrefaçon. Les organolanthanides ont été incorporés sans liaison covalente afin de préserver leursremarquables propriétés de luminescence et leur stabilité chimique. Deux types de nanoparticulesont été étudiés, des particules de latex et des billes de silice qui ont toutes les deux été synthétiséesen milieu hétérogène.La silice a été synthétisée par un procédé sol-gel en microémulsion inverse. Deux organolanthanidesluminescents initialement dissous dans les micelles inverses ont été piégés physiquement dans lasilice amorphe pendant sa formation. Une nouvelle méthode basée sur la quantification de l’activitéd’un isotope radioactif de l’Eu(III) a été développée pour étudier l’incorporation desorganolanthanides. Les propriétés physico-chimiques des organolanthanides influencent directementleur localisation au sein des particules et l’efficacité d’incorporation. L’étude approfondie de cesnanoparticules a permis de mettre en évidence une amélioration de la relaxivité d’un complexe deGd(III) quand il est confiné dans la silice.Les particules de latex ont été synthétisées par polymérisation radicalaire en miniémulsion directe.Différents organolanthanides de structures ionique ou non ionique ont été incorporés efficacementpar simple dissolution dans le monomère. L’incorporation du complexe de structure ionique anécessité l’utilisation d’un tensioactif cationique afin de le maintenir à l’intérieur des gouttelettes etgarantir son incorporation dans les particules de latex. Ce système permet d’incorporer un grandnombre de complexes et aucun relargage n’est observé après plusieurs mois. Le ligand utilisé permeten plus d’exciter jusqu’à dix terre rares simultanément. En faisant varier la nature et la quantité desorganolanthanides incorporés, il est ainsi possible de générer des codes optiques complexes sousune excitation unique. / This work deals with the elaboration of luminescent nanoparticles based on organolanthanides forbioimaging and optical coding. The organolanthanides were embedded without covalent linking inorder to preserve their remarkable luminescent properties and chemical stability. Two differenttypes of nanoparticles have been studied: polymer latexes and silica particles that were bothsynthesized in dispersed media.The silica nanoparticles were synthesized by a reverse microemulsion-mediated sol-gel process. Twoluminescent lanthanide chelates originally dissolved into water droplets were physically trapped intothe amorphous silica during its formation. A novel method based on a radioactive Eu(III) probe hasbeen developed to study the incorporation process. The physicochemical properties of the differentchelates had a strong influence on their localization within the particles and on the measuredincorporation efficiencies. This study finally allowed us to investigate the effect of Gd(III) complexesconfinement into silica nanoparticles.Luminescent polymer latexes based on organolanthanides have been synthesized by miniemulsionpolymerization. Several organolanthanides exhibiting a ionic structure or a non-ionic structure havebeen efficiently embedded into latex particles by simple dissolution in the corresponding monomers.For the ionic lanthanide chelate, a cationic surfactant was used to maintain the organolanthanidecomplex inside the droplets and guaranty and efficient incorporation. The resulting polymericluminescent nanoparticles showed excellent stability over leakage and a high loading capacity. Thisparticular ligand is able to efficiently sensitize over ten luminescent lanthanides, emitting in thevisible, the NIR or both regions. This allowed us to generate a large variety of color codes based onluminescence by tuning the emission signal using several lanthanide ions.

Cette thèse de Doctorat est rattachée au projet européen Eulafuel, visant à concevoir un biocarburant à partir des triterpènes du latex de l’épurge Euphorbia lathyris. Notre mission consiste à étudier l’origine biosynthétique des unités isopréniques constituant ces molécules. Proviennent-elles de la voie du mévalonate (MVA) et/ou de la voie du méthylérythritol phosphate (MEP) ? En premier lieu, nous avons mis au point un protocole de culture de la plante en conditions axéniques et comparé les profils triterpéniques de plantes cultivées dans différentes conditions. Nous avons ensuite montré, grâce à des expériences d’incorporation de précurseurs marqués au 13C et au 2H, que les isoprénoïdes d’E. lathyris étaient produits via la voie du MVA. La seconde partie de ce travail porte sur l’étude de l’origine biosynthétique d’isoprénoïdes de végétaux par GC-iRMS, une intéressante alternative aux expériences de marquage. Nous avons comparé les signatures isotopiques δD et δ13C des lipides provenant de huit organismes phototrophes et formulé plusieurs hypothèses permettant d’expliquer les différences de fractionnement isotopique observées. / This PhD thesis is included in a European project, Eulafuel, aiming to use latex triterpenes of caper spurge (Euphorbia lathyris) as a biofuel source. Our investigation focuses on the biosynthetic origin of isoprene units. Are they produced via mevalonate (MVA) pathway and/or methylerythritol phosphate (MEP) pathway? First, we proposed a procedure to cultivate E. lathyris in axenic conditions, and we compared triterpenic profiles from plants grown in different conditions. Then, we showed, by incorporating 13C- and 2H-labeled precursors, that E. lathyris isoprenoids were produced via MVA pathway. The second part of this work is based on an isotopic analysis of plant isoprenoids by GC-iRMS, an interesting alternative to labeling experiments. We compared isotopic signatures (δD and δ13C) of lipids arising from eight phototrophic organisms and we proposed several hypothesis to explain the isotopic fractionation differences we observed.

L’objectif de ce travail était d’étudier l’évolution de la morphologie des agrégats soumis à des conditions hydrodynamiques turbulentes. Pour cela, des expériences de floculation de particules de latex ont été réalisées dans un réacteur de Taylor-Couette en mettant en œuvre un séquençage des conditions hydrodynamiques, consistant en six étapes effectuées alternativement à faible et fort taux de cisaillement. Pour l’ensemble des expériences, un suivi en ligne de la taille des flocs a été réalisé par granulométrie laser. Par ailleurs, des paramètres caractéristiques de la forme des agrégats, ont été déterminés par analyse d’images sur des échantillons de suspension prélevés à la fin des différentes étapes du séquençage hydrodynamique. Dans le cas où le mécanisme de floculation est la neutralisation de charges (par ajout de NaCl ou de Al2(SO4)3), les résultats ont permis de confirmer la forte influence de l’hydrodynamique sur la taille des agrégats mais ont aussi révélé l’existence d’un lien entre la forme des agrégats et leur histoire. Contrairement à la taille, la morphologie des flocs, caractérisée par leur circularité ou leur convexité est peu sensible à l’hydrodynamique. L’étude des distributions surfaciques de ces paramètres de forme ainsi que la représentation des résultats expérimentaux sous forme bidimensionnelle (reliant taille et forme) ont en effet montré qu’après un certain nombre de cycles rupture-refloculation, la circularité comme la convexité évoluent vers une distribution unique, indépendante de l’hydrodynamique. Dans le cas où le mécanisme de floculation est le pontage (le polymère utilisé étant le PolyDADMAC), pour des taux de cisaillement faible, les agrégats sont plus grands, mais plus circulaires et plus résistants à la rupture que ceux créés par neutralisation de charge. Une analyse complémentaire est ensuite proposée permettant d’analyser l’effet des conditions hydrodynamiques sur la dimension fractale des flocs déduite des mesures par diffraction laser ou de l’analyse d’images. A des fins de comparaison, une nouvelle expression de la dimension fractale issue de l’analyse morphologique Df* a été introduite. Enfin, la modélisation de la floculation par résolution de l’équation de bilan de population basée sur la méthode de la quadrature des moments (QMOM) a été abordée ; les paramètres variables du modèle étant les valeurs expérimentales du taux de cisaillement moyen et la dimension fractale. Les résultats préliminaires montrent qu’il est possible de reproduire correctement l’évolution des six premiers moments de la distribution en taille des agrégats pour une phase d’agrégation du séquençage hydrodynamique. / The aim of this work was to investigate the evolution of the morphology of aggregates under turbulent hydrodynamic conditions. For this purpose, latex particles flocculation experiments were conducted in a Taylor-Couette reactor by carrying out a sequencing of the hydrodynamic conditions, consisting of six steps performed alternately at low and high shear rate. For all the experiments, an on-line monitoring of the size of the flocs was carried out by laser diffraction. Moreover, characteristic parameters of the shape of the aggregates were determined by image analysis on suspension samples taken at the end of the various stages of the hydrodynamic sequencing. When the flocculation mechanism is the charge neutralization (by addition of NaCl or Al2(SO4)3), the results have confirmed the strong influence of hydrodynamics on aggregate size but also revealed the existence of a relationship between the shape of the aggregates and their history. Contrary to size, the morphology of the flocs, characterized either by their circularity or convexity, is not sensitive to hydrodynamics. The study of the surface distributions of these shape parameters as well as the representation of the experimental results in two-dimensional form (linking size and shape) have shown that, after a number of breakage-reflocculation cycles, both circularity and convexity evolve towards a single distribution which is independent of hydrodynamics. When the bridging flocculation is the main mechanism (the polymer used being PolyDADMAC), at low shear rates, the aggregates are larger, but more circular and more resistant to breakage than those issued from charge neutralization. A complementary analysis is then proposed to analyze the effect of hydrodynamics on the fractal dimension measured either by laser diffraction or by image analysis. In order to compare both results, a new expression of the fractal dimension derived from the morphological analysis Df * was introduced. Finally, the modeling of the flocculation by solving the population balance equation using the quadrature method of moments (QMOM) is presented; the only variable parameters being the experimental values of the average shear rate and the fractal dimension. The preliminary results show that it is possible to reproduce correctly the evolution of the first six moments of the aggregate size distribution for an aggregation phase of the hydrodynamic sequencing.