La biocontamination des surfaces et les risques associés sont des enjeux majeurs économiques et de santé publique. Afin de limiter ou empêcher l’adhésion bactérienne, une des solutions possible consiste en la modification des propriétés des surfaces, afin de leur conférer les fonctions voulues. Dans ce contexte, l’objectif de cette étude est de modifier des surfaces de types métallique (acier) ou polymère : poly(téréphtalate d’éthylène) par des glycomonomères ou des monomères bioactifs. La stratégie de modification des surfaces s’effectue en plusieurs étapes.La première étape permet d’incorporer des fonctions réactives sur les surfaces par traitement acide puis réaction avec la dopamine, ou par traitement plasma ammoniaque. Des fonctions hydroxyle et amine sont introduites. Par la suite un amorceur de polymérisation par transfert d’atome est greffé sur les surfaces. Les monomères sont synthétisés et leur polymérisation étudiée en solution, dans un premier temps dans les conditions de polymérisation radicalaire classique, puis par polymérisation par transfert d’atome. Les conditions optimales sont déterminées, puis les polymérisations sur surfaces effectuées. La dernière étape concerne l’étude des propriétés microbiologiques des surfaces synthétisées.Les glycopolymères protégés et déprotégés de galactose ainsi que les polymères de méthacrylate de gaïacyle et de méthacrylate de thymyle ont été synthétisés. Les monomères ont été polymérisés par polymérisation par transfert d’atome à partir de la surface, sur les surfaces d’acier et de poly(téréphtalate d’éthylène). Après chaque étape de modification de surface, les matériaux ont été systématiquement caractérisés par goniométrie et spectroscopie à photoélectrons X. Les surfaces d’acier fonctionnalisées par le glycopolymère présentent des propriétés anti-adhésives vis-à-vis de Bacillus subtilis, un effet plus marqué est observé après greffage du glycopolymère déprotégé. Les surfaces de poly(téréphtalate d’éthylène) quant à elles, possèdent des propriétés anti-adhésives leur du greffage du poly(méthacrylate de thymyle) vis-à-vis de Listeria monocytogenes, Staphilococcus aureus et Pseudomonas aeruginosa. Un effet anti-biofilm a également été mis en évidence vis-à-vis de Staphilococcus aureus.En parallèle des homopolymères d’ammonium quaternaire et des copolymères obtenus en incorporant les monomères bioactifs ont été synthétisés. Les propriétés antibactériennes sont testées en milieu planctonique vis-à-vis de Bacillus subtilis. Un degré de polymérisation égal à 78 et les groupements halogénoalcane : iodométhane ou bromoéthane permettent l’obtention de la concentration minimale inhibitrice la plus faible. La présence des monomères bioactifs permettent la diminution de la concentration minimale inhibitrice. Le résultat le plus intéressant est obtenu lors de l’incorporation d’un pourcent de N-(4-hydroxy-3-méthoxy-benzyl)-acrylamide. / Bio-contamination of surfaces and related risks are very important economically and for public health. To prevent this phenomenon, one solution is to modify the properties of the surfaces, in order to give them the wanted functionalities. The goal of this study is the modification of metallic surfaces (steel) or polymer surfaces: poly(ethylene terephtalate) with glycomonomers or bioactives monomers. To reach this objective, a multi-step strategy is applied.The first step enabled the incorporation of reactive species on the surfaces by an acid treatment followed by a reaction with dopamine, or by ammonia plasma treatment. Hydroxyl or amine functional groups are added. Then, an initiator of atom transfer radical polymerization is grafted on surfaces. Monomers are synthesized and conventional polymerization and atom transfer radical polymerization are studied. Optimal conditions are determined and polymerization on surfaces achieved. The last step is the study of the microbiological properties of the synthesized surfaces.Protected and unprotected galactose glycopolymers as well as gaiacyl methacrylate and thymyl methacrylate have been synthesized. Monomers have been polymerized by atom transfer radical polymerization directly to the steel or poly(ethylene therephtalate) surfaces. After each step, materials are analyzed by contact angle measurements and X-ray photoelectron spectrometry.Steel surfaces which are functionalized by a glycopolymer and tested in presence of Bacillus subtilis are found to have antiadhesive properties. A most important effect is observed with the unprotected glycopolymer. Poly(ethylene terephtalate) surfaces have antiadhesive properties in presence of Listeria monocytogenes, Staphilococcus aureus and Pseudomonas aeruginosa when poly(thymyl methacrylate) is grafted. An antibiofilm effect is observed with Staphilococcus aureus.Simultaneously, quaternary ammonium homopolymers and copolymers by integration of bioactive monomers have been obtained. Their antibacterial properties are tested in planctonik conditions in presence of Bacillus subtilis. A degree of polymerization equal to 78 and alkyl halide groups: iodomethane and bromoethane enabled to obtain the lowest minimal inhibitory concentration. Bioactive monomers contributed to emphasize this decrease. The most decreasing effect is obtained when one per cent of N-(4-hydroxy-3-méthoxy-benzyl)-acrylamide is integrated.

L’incorporation de particules inorganiques dans une matrice polymère confère de nouvelles propriétés au matériau ou améliore de manière significative les propriétés déjà existantes. Cependant, l’apparence visuelle perçue, telle que la transparence, peut être altérée par des phénomènes de diffusion de la lumière par les particules. Cette diffusion de la lumière est principalement conditionnée par la dimension des particules –ou agrégats de particules- et la différence d’indice de réfraction entre la matrice et les charges. Afin de traiter ces deux problèmes, l’objectif de nos travaux était de contrôler simultanément l’état de dispersion des nanoparticules inorganiques dans la matrice polymère et l’indice de réfraction des nanoparticules de façon à l’ajuster à celui de la matrice. Pour élaborer ce nouveau composite, nous avons synthétisé des nanoparticules hybrides cœur@écorce avec un cœur inorganique qui apporte les nouvelles propriétés et une écorce polymère d’épaisseur contrôlée, obtenue par polymérisation radicalaire contrôlée par voie nitroxyde amorcée à la surface des nanoparticules inorganiques. L’écorce polymère limite l’agrégation des particules et permet de modifier l’indice de réfraction moyen des nanoparticules cœur@écorce. En contrôlant l’épaisseur et la nature chimique de l’écorce polymère, nous cherchons à ajuster l’indice de réfraction des nanoparticules cœur@écorce à celui de la matrice. Les nanoparticules ont ensuite été dispersées dans une matrice de poly(méthacrylate de méthyle). Les propriétés optiques des composites ont été caractérisées par spectrogoniophotométrie, afin d’obtenir des informations sur l’intensité et la distribution angulaire de la lumière transmise par le composite. La transparence des nanocomposites a été fortement améliorée en ajustant l’indice de réfraction des nanoparticules cœur@écorce à celui de la matrice. / The incorporation of inorganic particles into a polymer matrix confers new properties to the material or enhances significantly existing properties. However, the perceived visual appearance, such as loss of transparency, might be modified by the scattering of light by the particles. This light scattering is mainly due to the particle –or aggregates of particles- dimensions and the refractive index difference between matrix and fillers. In order to address both issues, the objective of the present work was to control simultaneously the dispersion state of the inorganic nanoparticles into the polymeric matrix and the refractive index of the nanoparticles to match the one of the matrix. To achieve this new composite, we designed hybrid core@shell nanoparticles with an inorganic core that brings new properties and a polymer shell of controlled thickness, obtained by surface-initiated nitroxide mediated controlled radical polymerization. The polymer shell limits the aggregation of the particles and enables us to tune the average refractive index of the hybrid core@shell particle. By controlling the thickness and the chemical nature of the polymeric shell, we targeted to match the refractive index of the hybrid core@shell particle to the one of the polymeric matrix. The nanoparticles were further dispersed into a poly(methyl methacrylate) matrix. Optical properties of composites were characterized by spectrogoniophotometry which gave us informations about the intensity and the angular distribution of the transmitted light by the nanocomposites. The transparency of the nanocomposites was strongly enhanced for core@shell particles fulfilling the refractive index matching conditions.

The design of biomaterials, historically initiated and developed by physicians and engineers, in the last decades has slowly shifted toward a more biochemical based approach. For the replacement, repair and regeneration of tissues scientists are now focusing on materials that stimulate specific biological response at the molecular level. These biomaterials have already shown interesting applications in cell proliferation, differentiation, and extracellular matrix production and organization when the material modifications are designed to elicit specific interactions with cell integrins. In the present work we propose the application of this strategy for the development of blood-compatible materials. We first identified, in the coagulation cascade a key enzyme that constitute a valuable biological target for the development of anti-thrombogenic compounds. Piperazinyl-amide derivatives of N-alfa-(3-trifluoromethyl-benzenesulfonyl)-L-arginine were synthesized as graftable thrombin inhibitors. These inhibitors provided a spacer arm for surface grafting and a fluorine tag for XPS (X-ray photoelectron spectroscopy) detection. The possible disturbance of biological activity due to a variable spacer-arm fixed on the N-4 piperazinyl position was evaluated in vitro against human alfa-thrombin, in silico by molecular modelling and via X-ray diffraction study. Selected inhibitors, having inhibition potency in the mM range, were grafted on polyesters surface via wet chemistry and photochemical activation treatments. Wet chemistry surface grafting was performed by specific hydroxyl chain-ends activation and resulted in bioactive molecules fixation of 20-300pmol/cm2. The photochemical grafting was performed using a molecular clip providing an aromatic azide, for nitrene insertion into a polymer, and an activated ester for grafting of tag compounds. This grafting technique resulted in a dramatic increase in fixed bioactive signals (up to nmol/cm2). The material blood-compatibilization induced by the surface fixation of the inhibitors, was measured by a static blood clot weight measurement test. The wet chemistry grafting technique resulted in moderate blood-compatibilization while by the photochemical grafting method important decrease in surface blood clot formation was observed. In the latter case, the blood response to material contact was found to be strongly affected by the polyester surface photo-degradation induced by the activation treatment.

The design of biomaterials, historically initiated and developed by physicians and engineers, in the last decades has slowly shifted toward a more biochemical based approach. For the replacement, repair and regeneration of tissues scientists are now focusing on materials that stimulate specific biological response at the molecular level. These biomaterials have already shown interesting applications in cell proliferation, differentiation, and extracellular matrix production and organization when the material modifications are designed to elicit specific interactions with cell integrins. In the present work we propose the application of this strategy for the development of blood-compatible materials. We first identified, in the coagulation cascade a key enzyme that constitute a valuable biological target for the development of anti-thrombogenic compounds. Piperazinyl-amide derivatives of N-alfa-(3-trifluoromethyl-benzenesulfonyl)-L-arginine were synthesized as graftable thrombin inhibitors. These inhibitors provided a spacer arm for surface grafting and a fluorine tag for XPS (X-ray photoelectron spectroscopy) detection. The possible disturbance of biological activity due to a variable spacer-arm fixed on the N-4 piperazinyl position was evaluated in vitro against human alfa-thrombin, in silico by molecular modelling and via X-ray diffraction study. Selected inhibitors, having inhibition potency in the mM range, were grafted on polyesters surface via wet chemistry and photochemical activation treatments. Wet chemistry surface grafting was performed by specific hydroxyl chain-ends activation and resulted in bioactive molecules fixation of 20-300pmol/cm2. The photochemical grafting was performed using a molecular clip providing an aromatic azide, for nitrene insertion into a polymer, and an activated ester for grafting of tag compounds. This grafting technique resulted in a dramatic increase in fixed bioactive signals (up to nmol/cm2). The material blood-compatibilization induced by the surface fixation of the inhibitors, was measured by a static blood clot weight measurement test. The wet chemistry grafting technique resulted in moderate blood-compatibilization while by the photochemical grafting method important decrease in surface blood clot formation was observed. In the latter case, the blood response to material contact was found to be strongly affected by the polyester surface photo-degradation induced by the activation treatment.

Diese Arbeit liefert die Grundlage für intelligente Beschichtungen aus kovalent gebundenen Polymeren, sogenannten Polymerbürsten, mit Schichtdicken von wenigen Nanometern. Durch ihre Fähigkeit die Oberflächeneigenschaften je nach Umgebungstemperatur, pH Wert und Zusammensetzung zu ändern, kann die Adsorption von Biomolekülen auf eine einzigartige Art und Weise kontrolliert und reguliert werden. Die zusätzliche Modifizierung der Polymerbürsten mit Elektronenstrahlen ermöglicht die Generierung von Gradienten und erweitert die Anwendungsmöglichkeiten in vielfältigen Bereichen der interdisziplinären Forschung, wie z.B. in Hinblick auf das Lab-on-Chip Design oder die Biomedizin. / Polymer brushes represent sensitive coatings with thicknesses of few nanometres and are interesting for interdisciplinary scientific research, e.g. for intelligent lab-on-chip design or biotechnology. It is demonstrated in this work, that polymer brushes are able to change their surface properties depending on the ambient conditions like solvent quality, temperature or pH value. This sensitivity highly influenced the adsorption of bio molecules. Especially mixed polymer brushes enabled the tuning of the adsorbed amount of various proteins and cells. To create surface gradients or structures in the different polymer brush surfaces, controlled electron beam modification was applied.

Οι νανοσωλήνες άνθρακα, από τη στιγμή της ανακάλυψής τους, έχουν προσελκύσει το ενδιαφέρον της επιστημονικής κοινότητας, λόγω της ευρείας εφαρμογής τους σε πολλά επιστημονικά και τεχνολογικά πεδία, ως συνέπεια των μοναδικών ιδιοτήτων τους. Σημαντική είναι η χρησιμοποίηση των νανοσωλήνων άνθρακα με σκοπό την ανάπτυξη μιας καινοτόμου μεμβράνης υψηλών αποδόσεων, για χρήση στην τεχνολογία Βιοαντιδραστήρα Μεμβρανών (Membrane Bioreactors, MBRs). Στην παρούσα εργασία, πραγματοποιήθηκε χημική τροποποίηση των νανοσωλήνων άνθρακα με πολυμερικές αλυσίδες. Η τροποποίηση των νανοσωλήνων μπορεί όχι μόνο να αυξήσει τη διαλυτότητά τους, αλλά να βελτιώσει την επεξεργασιμότητά τους και να τους προσδώσει νέες ιδιότητες, ανάλογα με τη φύση των μορίων της τροποποίησης. H τροποποίηση των νανοσωλήνων άνθρακα μπορεί να επιτευχθεί με την επισύναψη λειτουργικών ομάδων στην επιφάνειά τους, είτε μέσω ομοιοπολικού είτε μέσω μη ομοιοπολικού δεσμού. Η ομοιοπολική σύνδεση επιτυγχάνεται με δύο μεθόδους: τον “εμβολιασμό προς” και τον “εμβολιασμό από”. Στον “εμβολιασμό προς” το συντεθειμένο πολυμερές προσδένεται απευθείας στην επιφάνεια του νανοσωλήνα, ενώ στον “εμβολιασμό από” η πολυμερική αλυσίδα αναπτύσσεται πάνω στην επιφάνεια του νανοσωλήνα. Στη συγκεκριμένη εργασία, λεπτοί νανοσωλήνες άνθρακα πολλαπλού τοιχώματος (Thin MWCNTs) και νανοσωλήνες άνθρακα πολλαπλού τοιχώματος (MWCNTs) τροποποιήθηκαν ομοιοπολικά και με τις δύο μεθόδους με πολυμερή, τα οποία μπορούν να ενσωματώσουν είτε ομοιοπολικά είτε ηλεκτροστατικά ομάδες τεταρτοταγούς αζώτου και φωσφoνίου, οι οποίες παρουσιάζουν βιοστατικές ιδιότητες. Ειδικότερα, έγιναν προσπάθειες ομοιοπολικής πρόσδεσης των βιοστατικών ομάδων μέσω πολυμερισμού κατάλληλων μονομερών ή με πολυμερισμό των μονομερών και κατάλληλη χημική τροποποίησή τους στην επιφάνεια των νανοσωλήνων άνθρακα. Τα μονομερή ήταν ο 2-(διμεθυλάμινο) μεθακρυλικός αιθυλεστέρας (DMAEMA) και το τεταρτοταγές DMAEMA για τους MWCNTs, ενώ μια επιπλέον προσπάθεια πραγματοποιήθηκε για πολυμερισμό του Ν,Ν-[(διμεθυλάμινο)πρόπυλο]μεθακρυλαμιδίου (MADAP) στους Thin MWCNTs. Επειδή οι προσπάθειες δεν προχώρησαν σε σημαντικό βαθμό, συντέθηκε το στατιστικό συμπολυμερές P(AA12-co-VBCHAM) με συμπολυμερισμό του ακρυλικού οξέος (ΑΑ) και του 4-βινυλοβένζυλο χλωριδίου (VBC) σε ποσοστό 12% και 88% αντίστοιχα και εισαγωγή της N,N-διμεθυλοδεκαεξυλαμίνης, το οποίο στη συνέχεια εισήχθη στους τροποποιημένους, με ομάδες φαινόλης, νανοσωλήνες άνθρακα (CNTs-PhOH). Επίσης, επετεύχθη εισαγωγή των βιοστατικών ομάδων αμμωνίου και φωσφονίου μέσω ηλεκτροστατικής αλληλεπίδρασης ως αντισταθμιστικά ιόντα στον αρνητικά φορτισμένο πολυηλεκτρολύτη πολυ(στυρενοσουλφονικό νάτριο) (PSSNa), που είχε προσδεθεί στους τροποποιημένους, με ομάδες εκκινητή ATRP, (πολυμερισμός ελευθέρων ριζών μέσω μεταφοράς ατόμου) λεπτούς νανοσωλήνες άνθρακα πολλαπλού τοιχώματος (Τhin MWCNTs-Ph-INIT). Η ίδια διαδικασία πραγματοποιήθηκε για την εισαγωγή ομάδων αμμωνίου στο PSSNa που είχε προσδεθεί στους τροποποιημένους, με ομάδες εκκινητή ATRP, νανοσωλήνες άνθρακα πολλαπλού τοιχώματος (MWCNTs-Ph-INIT). Τα συντεθειμένα βιοστατικά υλικά μπορούν να χρησιμοποιηθούν σε πολλές εφαρμογές, μεταξύ των οποίων είναι και ο καθαρισμός του νερού. / Since their discovery, carbon nanotubes, have attracted the interest of the scientific community, because of their wide application in a numerous scientific and technological fields, as a consequence of their unique properties. The use of carbon nanotubes is of great importance to the field of Membrane Bioreactors (MBRs) for the development of innovative membranes of high performance. The modification of carbon nanotubes can not only increase their solubility, but improve their processability and give them new properties, depending on the nature of the molecules of modification. In this work, the chemical modification of carbon nanotubes with polymer chains is investigated. Modification of carbon nanotubes can be achieved with the attachment of functional groups in their surface, through covalent or non covalent bond. The covalent bond is achieved with two methods: “grafting to” and “grafting from”. In the “grafting to” method, the synthesized polymer is attached directly on the surface of carbon nanotube, while in the “grafting from” method, the polymer chain is developed from the surface of the carbon nanotube. In the present work, thin multi-walled carbon nanotubes (Thin MWCNTs) and multi-walled carbon nanotubes (MWCNTs) were modified covalently with both methods with polymers, that can incorporate either covalently or electrostatically, quartenary ammonium and phosphonium groups that present antifouling properties. More specifically, efforts were made in covalent attachment of antifouling groups via polymerization of suitable monomers or with polymerization of monomers and appropriate subsequent chemical modification in the surface of carbon nanotubes. The monomers were the 2-(Dimethylamino)ethyl methacrylate (DMAEMA) and quaternized DMAEMA for MWCNTs, while an additional effort was made in polymerization of N,N-[(dimethylamino)propyl]methacrylamide (MADAP) in Thin MWCNTs. Because the efforts were not successful, the random copolymer P(AA12-co-VBCHAM) was prepared, with copolymerization of acrylic acid (AA) and 4-vinylbenzyl chloride (VBC) in 12% and 88% percentage respectively and introduction of N,N-Dimethylhexadecylamine, which afterwards was introduced into modified, with phenol groups, carbon nanotubes (CNTs-PhOH). Furthermore, successful introduction of antifouling ammonium and phosphonium groups via electostatical interaction as counter ions in the negatively charged polyelectrolyte poly(sodium styrene sulfonate) (PPSNa) was accomplished. The polyelectrolyte was grafted onto modified, with ATRP (atom transfer radical polymerization) initiator groups, thin multi-walled carbon nanotubes (Thin MWCNTs-Ph-INIT). The same process was followed for the introduction of ammonium groups in PSSNa, which was grafted onto modified, with ATRP initiator groups, multi-walled carbon nanotubes (MWCNTs-Ph-INIT). The composed antifouling materials can be used in a lot of applications, including the water purification.

Diese Arbeit liefert die Grundlage für intelligente Beschichtungen aus kovalent gebundenen Polymeren, sogenannten Polymerbürsten, mit Schichtdicken von wenigen Nanometern. Durch ihre Fähigkeit die Oberflächeneigenschaften je nach Umgebungstemperatur, pH Wert und Zusammensetzung zu ändern, kann die Adsorption von Biomolekülen auf eine einzigartige Art und Weise kontrolliert und reguliert werden. Die zusätzliche Modifizierung der Polymerbürsten mit Elektronenstrahlen ermöglicht die Generierung von Gradienten und erweitert die Anwendungsmöglichkeiten in vielfältigen Bereichen der interdisziplinären Forschung, wie z.B. in Hinblick auf das Lab-on-Chip Design oder die Biomedizin. / Polymer brushes represent sensitive coatings with thicknesses of few nanometres and are interesting for interdisciplinary scientific research, e.g. for intelligent lab-on-chip design or biotechnology. It is demonstrated in this work, that polymer brushes are able to change their surface properties depending on the ambient conditions like solvent quality, temperature or pH value. This sensitivity highly influenced the adsorption of bio molecules. Especially mixed polymer brushes enabled the tuning of the adsorbed amount of various proteins and cells. To create surface gradients or structures in the different polymer brush surfaces, controlled electron beam modification was applied.

No description available.

No description available.

Electrochemical diazonium grafting offers versatile functionalization of chemically inert graphite under mild condition, which is particularly suitable for CNT composite modification. Tetrafluorinated carboxylphenyl diazonium grafting provides the most controllable functionalization chemistry allowing near monolayer levels of functionality on carbon nanotubes. The functional density was successfully quantified by anion selective dye-assay and X-ray photoelectron spectroscopy (XPS) of thiol-Au self-assembled monolayers (SAM) as a calibration reference. This technique enables monolayer functionality at the tips of carbon nanotube membranes for biomimetic pumps and valves as well as thin conductive layers for CNT-based high area electrochemical support electrodes. Double-walled carbon nanotube (DWCNT) membranes were functionalized with sterically bulky dye molecules with amine termination in a single step functionalization process. Non-faradic (EIS) spectra indicated that the functionalized gatekeeper by single-step modification can be actuated to mimic protein channel under bias. This functional chemistry on membranes resulted in rectification factors of up to 14.4 with potassium ferricyanide in trans-membrane electrochemical measurements. One step functionalization by electrooxidation of amines provides simple and promising functionalization chemistry for the application of CNT membranes. Carbon nanotubes (CNTs) are considered a promising catalyst support due to high surface area, conductivity and stability. But very few cases of asymmetric catalysis have been reported using CNTs as support. Three noncovalent functionalization approaches have been carried out to immobilize Rh-Josiphos complex on CNTs for asymmetric hydrogenation of dimethyl itaconate. Coordinated Rh catalyst on CNTs exhibited excellent activity and reuse ability even after seventh run in hydrogenation but no enantiomeric excess as expected for lacking a chiral directing ligand. The catalyst using pyrene absorption gave 100% yield and excellent enantiomer excess (>90%) but suffered from leaching into solution. The phosphotungstic acid (PTA) anchored catalyst gave 100% yield and higher ee (99%) and better reusability over pyrene absorbed catalyst but had significant leaching after the second run. At this point it remains a significant challenge to utilize CNTs as a chiral catalyst support.