Langmuir-monolayer formation at the air/water interface (A/W) can be achieved by spreading amphiphilic molecules on a liquid subphase and compressing them into an ordered arrangement. The use of the Langmuir-Blodgett technique (LB) to prepare ultra thin films on solid surfaces from monolayers at A/W has considerable utility for studying surface interactions. In particular, the phase behavior of polyhedral oligomeric silsesquioxanes (POSS) was examined using a combination of LB and Brewster angle microscopy (BAM).Polymer fillers have been shown to reduce the cost and often improve the properties of high performance polymer composites. The utility of POSS as a potential nanofiller in blends with polymers such as poly(dimethylsiloxane) (PDMS) and poly(vinylacetate) (PVAc) was explored using surface pressure-area per monomer isotherms (P-A) and BAM. Substantial morphological differences are seen between polymer blends with heptasubstituted trisilanol-POSS and fully condensed octasubstituted-POSS due to differences in subphase affinity.Several poly(1-alkene-alt-maleic anhydride) (PXcMA) polymers were studied at both the gas/liquid interface as Langmuir films and at the gas/solid interface as Langmuir-Blodgett thin films on silicon substrates. A 0.01 M HCl solution (pH~2) was used during film deposition to ensure the carboxylic acids were fully protonated. The PXcMA polymers included X=1-hexene, 1-octene, 1-decene, and 1-octadecene (represented as PHcMA, POcMA, PDcMA, and PODcMA respectively). The P-A isotherms of these polymers were consistent with those obtained previously.1Tensiometry was used to determine the critical micelle concentrations (c.m.c.) of variable molar mass poly(dimethylsiloxane-b-(3-cyanopropyl)methylsiloxane-b-dimethylsiloxane) (PDMS-PCPMS-PDMS) triblock copolymers and a poly(dimethylsiloxane-b-2-ethyl-2-oxazoline) diblock copolymer. Dynamic light scattering (DLS) corroborated interfacial tension results. The polymers exhibited well-defined temperature-independent c.m.c.'s. These measurements ensured that the synthesis of cobalt nanoparticles for biocompatible magnetic fluids occurred above the c.m.c. / Master of Science

Wood is a complex biocomposite that exhibits a high work of fracture, making it an ideal model for multiphase man-made materials. Typically, man-made composites demonstrate interfacial fracture at failure due to abrupt transitions between neighboring phases. This phenomenon does not occur in wood because gradual phase transitions exist between regions of cellulose, hemicellulose, and lignin and therefore adhesion between adjacent phases is increased. The formation of interphases occurs as a consequence of the self-assembly process which governs the formation of wood. If this process was understood more thoroughly, perhaps tougher man-made, biobased composites could be prepared. To study self-assembly phenomena in wood, a system composed of a model copolymer (pullulan abietate, DS=0.027) representing the lignin-carbohydrate complex (LCC) and a model surface for cellulose fibers was used. The self-assembly of the polysaccharide pullulan abietate (DS=0.027) onto a regenerated cellulose surface prepared using the Langmuir-Blodgett (LB) technique was studied via surface plasmon resonance (SPR). Rapid, spontaneous, and desorption-resistant cellulose surface modification resulted when exposed to the model LCC. Adsorption was quantified using the de Feijter equation revealing that between 9-10 anhydroglucose units (AGUs) adsorb per nm&178; of cellulose surface area when cellulose is exposed to pullulan abietate (DS=0.027) compared to the adsorption of 6.6 AGUs per nm&178; of cellulose surface area when cellulose is exposed to unsubstituted pullulan. / Master of Science

Au cours des 25 dernières années, l’intérêt pour l’utilisation de semi-conducteurs organiques comme couche active dans les transistors à effet de champ (TOECs), à la place du silicium, a crû spectaculairement. L’utilisation de polymères π-conjugués dans ce domaine a grandement entraîné cet essor. Au fil du temps, on observe une amélioration des performances atteintes contribuant à l’émergence de nouveaux matériaux. Par contre, différents paramètres tels que la mobilité et la stabilité demeurent moins impressionnants que ceux des semi-conducteurs à base de matériaux inorganiques. De meilleurs résultats pourraient être obtenus si le transport de charges se faisait sans entraves. Ainsi, une très bonne organisation au sein des matériaux utilisés est nécessaire. Dans cette optique, des polymères conjugués amphiphiles constitués d’unités thiéno [3,4-c] pyrrole-4,6-dione (TPD) ont été synthétisés. En se servant de la technique Langmuir-Blodgett (LB) pour optimiser l’organisation des molécules au sein des films, il a été possible de réaliser des films stables avec des pressions de collapse de 60 mN/m. Les microscopies à angle de Brewster (BAM) et à force atomique (AFM) nous ont démontré l’homogénéité des films à l’interface air-eau (BAM) et une fois transférés sur un substrat solide (AFM). L’orientation a été étudiée principalement par spectroscopie infrarouge à réflexion totale atténuée (ATR). D’autres techniques spectroscopiques comme l’UV-visible, la spectroscopie infrarouge de réflexion absorption par modulation de polarisation (PM-IRRAS) et l’ellipsométrie ont permis de corroborer les résultats obtenus via l’ATR. Les mesures ont permis de confirmer l’obtention de l’orientation préférentielle hors du plan. Pour compléter ce projet, des tests ont été effectués avec des transistors organiques. Des valeurs de mobilité intéressantes de 1,2 × 10-3 cm2/(V.s) ont été enregistrées pour des transistors obtenus à partir de films LB. / Over the past 25 years, interest in the use of organic semiconductors as active layers in field effect transistors (TFTs) instead of silicon has grown dramatically. The use of π-conjugated polymers in this area has greatly driven this growth. Over time, there has been an improvement in performance achieved contributing to the emergence of new materials. However, the performances of organic semiconductors remains inferior that of their inorganic counterpart regarding parameters such as the mobility and stability. Better results could be achieved if the charge transport was done without hindrance. Thus, a very good organiza- tion within the material is needed. In this regard, amphiphilic polymers based on thieno [3,4-c] pyrrole-4,6-dione (TPD) units were synthesized. By using the Langmuir-Blodgett technique (LB) to optimize the organization of the molecules within the films, it was possible to achieve stable films with a collapse pressure of 60 mN/m. Brewster angle (BAM) and atomic force (AFM) microscopies have demonstrated that homogeneous films are obtained at the air-water interface (BAM) and remain so once transferred onto a solid substrate (AFM). Orientation has been studied mainly by attenuated total reflection infrared spectroscopy (ATR). Other spectroscopic techniques such as UV-visible, absorption polarization modulation infrared reflection spectroscopy (PM-IRRAS) and ellipsometry have confirmed the ATR results. Measurements show that molecules adopted an edge-on orientation in the polymer films. To complete this project, organic transistors were fabricated. Interesting mobility values of 1.2 × 10-3 cm2/(V.s) were recorded for organic LB film transistors.

Cette thèse de doctorat étudie l’auto-assemblage de copolymères di-blocs et de nanoparticules métalliques à l’interface air-eau. Les nanoparticules métalliques peuvent interagir fortement avec la lumière grâce à l’oscillation collective des électrons de conduction. Ce phénomène, qu’on appelle le plasmon de surface localisé, offre d’importantes perspectives dans l’élaboration de matériaux optiques. Cependant, la force et la fréquence du plasmon de surface varient significativement en fonction de plusieurs paramètres dont l’arrangement des nanoparticules. Les copolymères à blocs, quant à eux, ont la capacité de former des domaines de morphologies définies à la surface de l’eau et représentent une voie simple pour organiser les nanoparticules en deux dimensions. Avec la technique Langmuir-Blodgett, il a été possible de former des monocouches composites de nanoparticules et de copolymères, et de les transférer sur des substrats solides. Les films composites Langmuir-Blodgett ont été caractérisés par microscopie à force atomique et par microscopie électronique en transmission. Plusieurs auto-assemblages, incluant des agrégats, des systèmes cœur-satellites, des cercles et des lignes de nanoparticules ont été observés. Les caractéristiques structurales de ces assemblages peuvent être ajustées avec précision en modifiant l’organisation des copolymères et la longueur des ligands thioalcanes à la surface des nanoparticules. De plus, une procédure de recroissance in situ a été développée pour augmenter la taille des nanoparticules incorporées sans altérer l’ordre des monocouches. Les propriétés optiques des auto-assemblages ont ensuite été étudiées expérimentalement et comparées à des simulations théoriques par l’approximation aux dipôles discrets. Une attention particulière a été portée aux nanocercles qui sont des structures hautement symétriques et compliquées à obtenir avec d’autres méthodes. Enfin, la thèse se termine par une série d’expériences préliminaires destinées à évaluer l’utilité de ce type de monocouches pour des applications de détection. / The present Ph. D. thesis treats the investigation of the self-assembly of block copolymers and metallic nanoparticles at the air-water interface. Metallic nanoparticles interact strongly with light because of the collective oscillation of the conduction electrons. This phenomenon is called the localized surface plasmon resonance and offer significant promise in the development of optical materials. However, the strength and frequency of the surface plasmon depend on several parameters, including details of the arrangement of the nanoparticles. As block copolymers can form nanodomains at the surface of water, they represent a simple way to organize nanoparticles in two dimensions. With the help of the Langmuir-Blodgett technique, it has been possible to form composite monolayers composed of nanoparticles and block copolymers, which are transferable on solid substrate. The Langmuir-Blodgett composite films have been characterized both by atomic force microscopy and transmission electron microscopy. Several self-assemblies, including aggregates, core-satellite structures, nanorings, and particle lines have been observed. The structural characteristics of these assemblies can be tuned precisely by modifying the copolymer organization and the capping ligand length at the nanoparticle surface. In addition, an in situ regrowth procedure has been developed to increase the size of the incorporated nanoparticles without losing the order of the monolayers. Then, optical properties of the self-assemblies have been investigated experimentally and compared to theoretical calculations by the discrete dipole approximation. Particular attention has been paid to the nanoring structures, which are highly symmetrical and complicated to obtain with other fabrication procedures. Finally, the thesis presents a series of preliminary experiments intended to assess the usefulness of the monolayers for sensing applications.

Les nombreuses morphologies périodiques des copolymères blocs sont bien connues. L'immiscibilité des blocs de nature chimique différente conduit à une séparation de phases à l'échelle moléculaire. Cette caractéristique propose une voix intéressante pour la préparation de surfaces nano-structurées. La couche monomoléculaire du poly(acrylate de tert-butyle)-bloc-poly(méthacrylate de méthyle) déposée à l'interface air-eau produit une séparation de phases en deux dimensions qui donne lieu à une surface composée de domaines. La taille de ces domaines correspond aux dimensions moléculaires qui sont elles-mêmes reliées aux masses moléculaires des blocs. Cette structure est conservée lors du transfert de la monocouche sur un substrat solide par la technique de Langmuir-Blodgett et la morphologie peut donc être étudiée par la microscopie à force atomique (AFM). Nos recherches portent sur l'étude de la taille et de l'organisation de ces domaines dans les films monomoléculaires. Nous avons synthétisé le poly(acrylate de tert-butyle) et le poly(acrylate de tert-butyle)-bloc-poly(méthacrylate de méthyle) par polymérisation anionique afin d'obtenir des échantillons monodisperses de différentes masses molaires. Par la suite, la morphologie des films minces monomoléculaires est étudiée par la microscopie à force atomique. Les images de microscopie à force atomique montrent une structure périodique composée de domaines. Étonnamment, des images semblables sont obtenues pour les échantillons d'homopolymères. Une hypothèse envisagée est que l'utilisation d'a-méthyle styrène lors de l'initiation de la polymérisation pourrait donner un très pefit bloc poly(a-méthyle styrène) au début de la molécule et ainsi induire la formation de micelles. Des images AFM de nouveaux polymères synthétisés sans l'a-méthyle styrène ne montrent pas la présence de domaines. Donc, il n'y aurait pas, dans ce cas, présence de micelles de surfaces à l'interface air-eau.

L'auto-assemblage des copolymères à bloc (CPBs) attire beaucoup d'intérêt grâce à leur capacité de générer spontanément des matériaux ordonnés avec des propriétés uniques. Les techniques Langmuir-Blodgett (LB) et Langmuir-Schaefer (LS) sont couramment utilisées pour produire des monocouches ou des films ultraminces à l'interface air/eau suivi de transfert aux substrats solides. Les films LB/LS de CPBs amphiphiles s'auto-assemblent dans des morphologies variables dépendamment de la composition du CPB ainsi que d'autres facteurs. Dans notre travail, nous avons étudié les films LB/LS de polystyrène-b-poly(4-vinyl pyridine) (PS-P4VP) et leurs complexes supramoléculaires avec le naphtol (NOH), l'acide naphtoïque (NCOOH) et le 3-n-pentadécylphenol (PDP). La première partie de ce mémoire est consacré à l'investigation du PS-P4VP complexé avec le NOH et le NCOOH, en comparaison avec le PS-P4VP seul. Il a été démontré qu'un plateau dans l'isotherme de Langmuir, indicatif d'une transition de premier ordre, est absent à des concentrations élevées des solutions d'étalement des complexes. Cela a été corrélé avec l'absence de morphologie en nodules avec un ordre 2D hexagonal à basse pression de surface. L'ordre au-delà de la pression de cette transition, lorsque présente, change à un ordre 2D carré pour tout les systèmes. La deuxième partie du la mémoire considère à nouveau le système PS-P4VP/ PDP, pour lequel on a démontré antérieurement que la transition dans l'isotherme correspond a une transition 2D d'un ordre hexagonal à un ordre carré. Cela est confirmé par microscopie à force atomique, et, ensuite, on a procédé à une étude par ATR-IR des films LB pour mieux comprendre les changements au niveau moléculaire qui accompagnent cette transition. Il a été constaté que, contrairement à une étude antérieure dans la littérature sur un autre système, il n'y a aucun changement dans l'orientation des chaînes alkyles. Au lieu de cela, on a découvert que, aux pressions au-delà de celle de la transition, le groupe pyridine, qui est orienté à basse pression, devient isotrope et qu'il y a une augmentation des liaisons hydrogènes phénol-pyridine. Ces observations sont rationalisées par un collapse partiel à la pression de transition de la monocouche P4VP, qui à basse pression est ordonné au niveau moléculaire. Cette étude a mené à une meilleure compréhension des mécanismes moléculaires qui se produisent à l'interface air/eau, ce qui fournit une meilleure base pour la poursuite des applications possibles des films LB/LS dans les domaines de nanotechnologie. / Self-assembly of block copolymers (BCPs) attracts much interest due to their ability to spontaneously generate ordered materials with unique properties. For many applications, such as masks in nanolithography, separation membranes in medical diagnostics, and nanotemplates for nanowire fabrication, manufacturing into thin films is required. The Langmuir-Blodgett (LB) and Langmuir-Schaefer (LS) techniques are commonly used to produce ultrathin or monolayer films at the air/water interface that are transferred to solid substrates. LB/LS films of amphiphilic BCPs self-assemble into various morphologies, depending on the BCP composition and other factors. In our work, we investigated LB/LS films of polystyrene-b-poly(4-vinyl pyridine) (PS-P4VP) and their supramolecular complexes with, naphthol (NOH), naphthoic acid (NCOOH) and 3-n-pentadecylphenol (PDP). The first part of the thesis was devoted to the investigation of PS-P4VP complexes with NOH and NCOOH, in comparison to PS-P4VP alone. It was shown that a plateau in the Langmuir isotherm, indicative of a first-order transition, is absent at high spreading solution concentrations for the complexes. This was correlated with an absence of the expected dot morphology with 2D hexagonal-like order at low surface pressure. Above the transition, when present, the morphology has 2D square order. The second part of the thesis re-examines the PS-P4VP/PDP system, which was previously shown to undergo a transition from 2D hexagonal to square order at the isotherm plateau pressure. This was confirmed here, and a detailed ATR-IR study of LB films was then undertaken to better understand molecular-level changes occurring at this transition. It was found that, contrary to another study in the literature on a different system, there is no change in alkyl chain orientation. Instead, it was found that the pyridine group loses its low-pressure orientation and there is increased phenol-pyridine hydrogen-bonding above the transition pressure, which is rationalized by a partial collapse of the low-pressure molecularly ordered P4VP monolayer at the transition pressure. This study leads to an improved understanding of the processes occurring at the air/water interface, which is a basis for the further possible applications of LB/LS films in nanotechnologies.

O ácido politiofeno acético (PTAA) é um derivado do politiofeno bastante versátil. Sua solubilidade em alguns solventes orgânicos e em soluções básicas aquosas lhe confere extensa processabilidade na forma de filmes finos, característica importante para dispositivos e sensores. Neste trabalho, investigou-se a formação de filmes de PTAA com as técnicas de automontagem e Langmuir-Blodgett (LB). Os filmes automontados foram preparados com dois policátions, hidrocloreto de poli-alilamina (PAH) e cloreto de poli-dialildimetilamônio (PDAC). O crescimento dos filmes depende do pH das soluções e do tipo de policátion, sugerindo dependência do mecanismo de crescimento com as interações específicas polímeropolímero. A conformação do PTAA em filme tem correlação com sua conformação em solução, apontando para um efeito de memória. Por outro lado, a energia de superfície destes filmes não sofre influência da arquitetura nem dessas diferenças conformacionais. Ou seja, embora o volume do filme possa ser distinto, as superfícies possuem propriedades semelhantes. A morfologia dos filmes foi caracterizada a partir de imagens de AFM utilizando conceitos de geometria fractal e estatística. A dimensão fractal dos filmes é semelhante, indicando o mesmo processo de crescimento dos filmes, independentemente das condições da deposição. Os filmes obtidos em pH ácido tinham tamanho de grão e comprimentos de correlação maiores, sugerindo a deposição de cadeias mais enoveladas. Foi possível fabricar filmes autossustentados sem degradação aparente do material a partir de filmes automontados de PAH/PTAA, entrecruzando termicamente os grupos ácido carboxílico e amina. Este é o primeiro relato de filmes deste tipo com derivado do politiofeno. Os filmes LB de PTAA foram obtidos sem adjuvantes, mas as condições de deposição precisam ser aprimoradas. Para explorar a elevada afinidade química entre compostos contendo enxofre e metais pesados, filmes foram utilizados para detecção espectroscópica e eletroquímica. Espectros de fotoluminescência e UV-Vis demonstraram que os metais interagem apenas com os estados excitados resultando na supressão da fluorescência; no entanto, sem especificidade e apenas para longos períodos de exposição. Espectros de FTIR mostraram a presença dos sais na matriz dos filmes. Por sua vez, voltametrias cíclicas permitiram detectar Pb+2 e Hg+2, mas a irreversibilidade dos processos eletroquímicos, causando alargamento dos picos de oxirredução, inviabiliza a detecção simultânea. / Polythiophene acetic acid (PTAA) is a versatile polythiophene derivative. Its solubility in some organic solvents and in basic aqueous solutions makes it attractive for processing thin films, an important feature for the fabrication of devices and sensors. In this thesis, we investigate the formation of PTAA films using the layer-by-layer (LbL) and the Langmuir- Blodgett (LB) techniques. The LbL films were prepared with poly(allylamine hydrochloride) (PAH) and poly(diallydimethylammonium chloride) (PDAC), with film growth depending on the pH of the solutions and type of polycation, thus indicating that the growth mechanism depends on polymer-polymer interactions. The conformation of the PTAA molecules in solid state was correlated with that in solution, in a kind of memory effect. The surface energy of the films was not affected by the film architecture or different conformations. The film morphology was characterized with AFM images using concepts of fractal geometry and statistics. The fractal dimension was similar for all films, and therefore the overall growth obeys the same process regardless of the deposition conditions. Nevertheless, films obtained at acidic pH exhibited larger grain size and correlation lengths than those produced at basic pHs, suggesting deposition of more coiled chains. It was also possible to fabricate selfsustained films without apparent PTAA degradation from the PAH/PTAA LbL films, upon thermal crosslinking of carboxylic acid and amine groups. This is the first report of such films with a polythiophene derivative. LB films of PTAA were obtained without co-spreading materials, but the deposition conditions need to be optimized. To explore the high chemical affinity between PTAA and compounds containing sulfur and heavy metals, some films were used for spectroscopic and electrochemical detection. The UV-Vis and photoluminescence spectra indicated that the metals affect only the excited states, leading to fluorescence quenching after long exposure times and without specificity for the metals. The FTIR spectra pointed to salts in the films. Pb+2 and Hg+2 ions could be detected using cyclic voltammetry, but their simultaneous detection was hampered by the irreversibility of the electrochemical processes which caused broadening of the oxi-reduction peaks.

O ácido politiofeno acético (PTAA) é um derivado do politiofeno bastante versátil. Sua solubilidade em alguns solventes orgânicos e em soluções básicas aquosas lhe confere extensa processabilidade na forma de filmes finos, característica importante para dispositivos e sensores. Neste trabalho, investigou-se a formação de filmes de PTAA com as técnicas de automontagem e Langmuir-Blodgett (LB). Os filmes automontados foram preparados com dois policátions, hidrocloreto de poli-alilamina (PAH) e cloreto de poli-dialildimetilamônio (PDAC). O crescimento dos filmes depende do pH das soluções e do tipo de policátion, sugerindo dependência do mecanismo de crescimento com as interações específicas polímeropolímero. A conformação do PTAA em filme tem correlação com sua conformação em solução, apontando para um efeito de memória. Por outro lado, a energia de superfície destes filmes não sofre influência da arquitetura nem dessas diferenças conformacionais. Ou seja, embora o volume do filme possa ser distinto, as superfícies possuem propriedades semelhantes. A morfologia dos filmes foi caracterizada a partir de imagens de AFM utilizando conceitos de geometria fractal e estatística. A dimensão fractal dos filmes é semelhante, indicando o mesmo processo de crescimento dos filmes, independentemente das condições da deposição. Os filmes obtidos em pH ácido tinham tamanho de grão e comprimentos de correlação maiores, sugerindo a deposição de cadeias mais enoveladas. Foi possível fabricar filmes autossustentados sem degradação aparente do material a partir de filmes automontados de PAH/PTAA, entrecruzando termicamente os grupos ácido carboxílico e amina. Este é o primeiro relato de filmes deste tipo com derivado do politiofeno. Os filmes LB de PTAA foram obtidos sem adjuvantes, mas as condições de deposição precisam ser aprimoradas. Para explorar a elevada afinidade química entre compostos contendo enxofre e metais pesados, filmes foram utilizados para detecção espectroscópica e eletroquímica. Espectros de fotoluminescência e UV-Vis demonstraram que os metais interagem apenas com os estados excitados resultando na supressão da fluorescência; no entanto, sem especificidade e apenas para longos períodos de exposição. Espectros de FTIR mostraram a presença dos sais na matriz dos filmes. Por sua vez, voltametrias cíclicas permitiram detectar Pb+2 e Hg+2, mas a irreversibilidade dos processos eletroquímicos, causando alargamento dos picos de oxirredução, inviabiliza a detecção simultânea. / Polythiophene acetic acid (PTAA) is a versatile polythiophene derivative. Its solubility in some organic solvents and in basic aqueous solutions makes it attractive for processing thin films, an important feature for the fabrication of devices and sensors. In this thesis, we investigate the formation of PTAA films using the layer-by-layer (LbL) and the Langmuir- Blodgett (LB) techniques. The LbL films were prepared with poly(allylamine hydrochloride) (PAH) and poly(diallydimethylammonium chloride) (PDAC), with film growth depending on the pH of the solutions and type of polycation, thus indicating that the growth mechanism depends on polymer-polymer interactions. The conformation of the PTAA molecules in solid state was correlated with that in solution, in a kind of memory effect. The surface energy of the films was not affected by the film architecture or different conformations. The film morphology was characterized with AFM images using concepts of fractal geometry and statistics. The fractal dimension was similar for all films, and therefore the overall growth obeys the same process regardless of the deposition conditions. Nevertheless, films obtained at acidic pH exhibited larger grain size and correlation lengths than those produced at basic pHs, suggesting deposition of more coiled chains. It was also possible to fabricate selfsustained films without apparent PTAA degradation from the PAH/PTAA LbL films, upon thermal crosslinking of carboxylic acid and amine groups. This is the first report of such films with a polythiophene derivative. LB films of PTAA were obtained without co-spreading materials, but the deposition conditions need to be optimized. To explore the high chemical affinity between PTAA and compounds containing sulfur and heavy metals, some films were used for spectroscopic and electrochemical detection. The UV-Vis and photoluminescence spectra indicated that the metals affect only the excited states, leading to fluorescence quenching after long exposure times and without specificity for the metals. The FTIR spectra pointed to salts in the films. Pb+2 and Hg+2 ions could be detected using cyclic voltammetry, but their simultaneous detection was hampered by the irreversibility of the electrochemical processes which caused broadening of the oxi-reduction peaks.

18-methyl eicosanoic acid (18-MEA), which is a branched fatty acid, is found at the outermost surface of mammalian hair with other straight-chain fatty acids such as palmitic acid and stearic acid. However, the precise role of 18-MEA is not yet completely understood. 18-MEA on Cadmium chloride subphase forms curvature at the water/air interface, leading to the formation of 3D-domains that can be easily transferred into solid support allowing to create complex and multi-functional structures. This project investigates if a non-toxic subphase would also lead to the formation of 3D-domains or if it is an intrinsic property of Cadmium chloride; and to investigate if the domain properties were tuneable. A combination of the Langmuir trough and the Atomic Force Microscopy is used. It is shown that a toxic subphase is not necessary and a more benign sodium subphase can be used to obtain 3D-domains. It is also shown that different chains length interact dissimilarly with the branched fatty acid. This results in the formation of very various structures. It is also shown that the subphase, the surface pressure of deposition and the composition of the fatty acid in the monolayer affect the properties of the domain, leading to different size of domain but also different morphology in the domain. Circular domains, elongated domains, continuous labyrinthine structures, dendritic centipede-like structures and no domains are obtained. / På den yttersta ytan av däggdjurshår återfinns den grenade fettsyran 18-methyleikosansyra tillsammans en mindre mängd av de raka fettsyrornapalmitinsyra och stearinsyra. Den exakta rollen av 18-MEA är dock ännu inte heltklarlagd. Ett monoskikt av 18-MEA på en subfas innehållande kadmiumklorid påtvingar en krökning av vatten–luftgränsytan. Det leder till bildandet av 3D-domäner som lätt kan överföras från vattenytan till fasta ytor vilket möjliggör att dekorera dessa ytor med komplexa och multifunktionella strukturer. Detta projekt undersöker om andra, miljövänliga motjoner i subfasen också skulle leda till bildandet av 3D-domäner eller om det är en inneboende egenskap hos kadmiumklorid. Det här ger även insikt om hur motjoner kan användas för att påverka och kontrollera domänbildningen. En kombination av Langmuirtråg och atomkraftsmikroskopi används för att karakterisera monoskikten. Det visas att en subfas innehållande kadmium inte är nödvändig och att en mer miljövänlig natriumsubfas kan användas för att bilda 3D-domäner. Det visas också att olika kedjors längd interagerar olika med den grenade fettsyran 18-MEA, vilket resulterar i bildandet av olika strukturer i deponerade monoskikt. Det visas också att yttrycket vid deponering och sammansättningen av fettsyror i mono skiktet påverkar egenskaperna hos monoskiktet, vilket leder till varierande storlek och struktur på de bildade domänerna, där cirkulära och långsträckta domäner, kontinuerliga labyrintstrukturer och dendritiska tusenfotingsliknande strukturer observeras.

Au cours de ce travail, nous nous sommes intéressés à l'élaboration de cristaux photoniques colloïdaux d'architecture contrôlée afin d'étudier leur effet sur les spectres de photoluminescence de luminophores. Notre stratégie a été d'incorporer les émetteurs au sein des particules de silice composant les cristaux colloïdaux de façon à les répartir de manière homogène dans l'ensemble des matériaux. Nous présentons la synthèse des précurseurs minéraux et l'élaboration de cristaux colloïdaux d'épaisseur contrôlée à la couche près grâce à la technique de Langmuir-Blodgett. Ces structures sont caractérisées par une bande interdite qui affecte la propagation de la lumière. L'insertion d'une couche de particules de diamètre différent dans un cristal colloïdal induit l'apparition d'une bande passante au sein de la bande interdite. Nous avons ainsi étudié l'influence de la structure de cristaux avec et sans défaut(s) sur les spectres d'émission de différents luminophores. Nous avons observé une inhibition et une exaltation locale de la lumière émise dans les zones spectrales correspondant respectivement aux bandes stoppante et passante. Nous avons également observé des modifications réversibles des spectres de photoluminescence des émetteurs, lorsque ceux-ci sont incorporés au sein de cristaux colloïdaux dont les propriétés optiques peuvent être modulées via l'application d'un stimulus extérieur.