There is an emerging interest in the development of sustainable materials with high performance. Cellulose is promising in this regard as it is a renewablere source with high specific properties, which can be utilized as strong reinforcements in novel biocomposites. However, to fully exploit the potential ofcellulose, its inherent hydrophilic character has to be modified in order toimprove the compatibility and interfacial adhesion with the more hydrophobicpolymer matrices commonly used in composites.In this study, the grafting of poly(ε-caprolactone) (PCL) and poly(L-lactide)(PLLA) from cellulose surfaces, via ring-opening polymerization (ROP) of ε-caprolactone and L-lactide, was investigated. Both macroscopic and nano-sizedcellulose were explored, such as filter paper, microfibrillated cellulose (MFC),MFC-films, and regenerated cellulose spheres. It was found that thehydrophobicity of the cellulose surfaces increased with longer graft lengths, andthat polymer grafting rendered a smoother surface morphology.To improve the grafting efficiency in the ROP from filter paper, both covalent(bis(methylol)propionic acid, bis-MPA) and physical pretreatment (xyloglucanbisMPA)were explored. The highest grafting efficiency was obtained with ROPfrom the bis-MPA modified filter papers, which significantly increased amountof polymer on the surface, i.e. the thickness of the grafted polymer layer.MFC was grafted with PCL to different molecular weights. The dispersability innon-polar solvent was obviously improved for the PCL grafted MFC, incomparison to neat MFC, and the stability of the MFC suspensions was better maintained with longer grafts. PCL based biocomposites were prepared from neat MFC and PCL grafted MFCwith different graft lengths. The polymer grafting improved the mechanical properties of the composites, and the best reinforcing effect was obtained when PCL grafted MFC with the longest grafts were used as reinforcement.A bilayer laminate consisting of PCL and MFC-films grafted with different PCL graft lengths displayed a gradual increase in the interfacial adhesion with increasing graft length.The effect of grafting on the adhesion was also investigated via colloidal probeatomic force microscopy at different temperatures and time in contact. A significant improvement in the adhesion was observed after polymer grafting. / QC 20100730

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Maîtriser la biocontamination surfacique et les risques susceptibles d’y être associés demeure un challenge majeur. Cette maîtrise passe par la préparation de nouveaux matériaux polymères possédant des propriétés de surface adaptées. Dans cette optique le LCOM développe depuis quelques années une thématique consistant à mettre au point des méthodes de modifications de surfaces de matériaux polymères par greffage de biomolecules. [ ] [ ] [ ] Dans ce contexte, l’objectif de cette étude est de fonctionnaliser des films polymères de type poly (téréphtalate d’éthylène) (PET) avec des dérivés sucrés et/ou polysaccharides dans le but d’étudier le caractère bactériostatique, biocide et pro ou anti-adhésion. [ ] La préparation des matériaux se fait en plusieurs étapes :Etape 1 : Fonctionnalisation de surfaces polymères (films) par traitement plasma N2/H2 et NH3 pour introduire à la surface des fonctions amines. Cette technique modifie la surface sans changer les propriétés intrinsèques des matériaux.Etape 2 : Greffage d’un amorceur de polymérisation radicalaire par transfert d’atome (ATRP)Etape 3 : Polymérisation en surface d’un monomère sucré par ATRP (contrôle de la longueur des chaînes greffées). La mise au point des paramètres de polymérisation ATRP de ces monomères est d’abord menée en solution avant d’étudier la polymérisation en surface.Etape 4 : Etudes microbiologiques des surfaces modifiées.Après chaque étape de modification de surface, les matériaux sont caractérisés par différentes méthodes d’analyses telles que : la spectroscopie de photoélectrons X (XPS), la microscopie à force atomique, la chromatographie d’exclusion stérique. Des glycopolymères protégés et déprotégés issus du galactose et de la glucosamine ont été synthétisés. Ceux issus de la glucosamine ont été synthétisés afin de mimer les propriétés antibactériennes du chitosane. Le glycomonomère issu du galactose est polymérisé par ATRP par voie « grafting from » sur des surfaces de PET. Ces surfaces modifiées présentent des propriétés anti-adhésives intéressantes contre les bactéries du type Bacillus subtilis. En effet, après greffage du glycomonomère déprotégé, il n’ ya plus d’adhésion de bactéries. Des polymères contenant des fonctions ammonium quaternaire et fluor ont aussi été greffés avec succès sur les films de PET par la même méthode. / Control surface contamination by microorganism is of great concern in a variety of areas such as food packaging, medical devices, hospitals and so on. To reduce or prevent microbial adhesion, new polymer surfaces must be developed. In this context, we investigate a new theme which deals with the modification of polymer materials containing carbohydrate molecules. , , The aim of the study is to attach covalently glycopolymers or potential antimicrobial polymers on films of polyethylene terephthalate (PET) in order to study the biocidal or anti-fooling properties. Indeed, grafting glycopolymers on PP fibers have brought anti-fooling properties. The surfaces are prepared in several steps:Step 1: Incorporation of primary amino groups by N2/H2 or NH3 plasma treatment. The pretreatment by plasma exhibits many benefits for the surface modification, which enables to introduce functional groups at the surface without any modification of the chemical and mechanical properties of the material during the process.Step 2: Insertion of Atom Transfer Radical Polymerization (ATRP) initiatorStep 3: Grafting from surface polymerization method of a monomer in order to control the molecular weight distribution on the surfaces. ATRP parameters of glycomonomers are studied in solution before carrying polymerization on surfaces.Step 4: Microbial adhesion tests of modified surfaces with Bacillus Subtilis and Lactoccocus Lactis as bacterial strains. Several analytical techniques such as X-ray photoelectron spectroscopy (XPS), Atomic Force Microscopy, size exclusion chromatography of polymers obtained in solution have been used to characterize the modified surfaces. The first step was to optimize plasma parameters in order to have a high density of primary amino group on the surfaces. Then several monomers have been studied especially glycomonomers from galactose and glucosamine to mimic antimicrobial properties of chitosan. Protected and deprotected glycopolymers from galactose polymerized on PET surfaces exhibit anti-fooling properties toward Bacillus Subtilis. Polymers containing quaternary ammonium salt or fluor have also been successfully polymerized by a grafting from method on PET films.

Dans le cadre des procédés de clarification d'eau de surface, les flocs formés au cours des étapes de coagulation et de floculation peuvent être séparés de l'eau traitée par décantation ou par flottation. Dans ce dernier cas, le procédé actuellement en vigueur est la flottation à air dissous et présente un certain nombre d'inconvénients. Ainsi, dans ce contexte, la présente thèse consiste à développer un matériau innovant, à la fois flottant et floculant, pour une application dans un procédé de flottation sans air. Dans un premier temps, l'élaboration de billes de polystyrène expansibles utilisant l'eau ou l'éthanol comme agent gonflant a été réalisée. D'autres billes ont ensuite été préparées en présence de 4-(chlorométhyl)styrène comme co-monomère puis la polymérisation par transfert d'atome amorcée en surface (SI-ATRP) de l'acrylamide a été effectuée avec succès. L'impossibilité d'expanser ces matériaux a ensuite conduit à l'exploration de nouvelles voies de synthèse avec la fonctionnalisation de matériaux flottants existants par des techniques de « grafting from » ou « grafting onto ». Quelle que soit la voie envisagée, la première étape a consisté à réduire les fonctions nitrile en amine primaire en présence d'hydrure d'aluminium lithium. Après fonctionnalisation par du bromure de bromoisobutyryle ou du chlorure d'acryloyle, il a été possible de venir greffer de l'acrylamide par SI-ATRP ou de l'amidon via un amorceur redox, respectivement. Les matériaux flottants/floculants obtenus ont été testés lors de flottatests. Les meilleurs résultats ont été obtenus avec les microsphères fonctionnalisées par de l'amidon anionique. Ces dernières ont permis d'abattre la turbidité de l'eau, ont ensuite été régénérées avec succès, par des bains d'acide oxalique ou de dithionite de sodium, et employées durant plusieurs cycles flottatest/régénération avec des résultats reproductibles. / At the end of clarification process, after coagulation-flocculation steps, flocs can be removed from treated water by settling or flotation. In the latter case, Dissolved Air Flotation is the currently used process. However, this method showed important drawbacks, especially an important energetic cost due to the production of air saturated water. In that context, the goal of the reported work dealt with achieving air-free flotation using innovative floating materials. First of all, the synthesis of expandable polystyrene beads using water or ethanol as blowing agent was investigated. Other beads containing both styrene and 4-(chloromethyl)styrene were prepared. Then, surface initiated atom transfer radical polymerization of acrylamide (SI-ATRP) was achieved. Unfortunately, the expansion of such materials was not possible. Therefore, the second part focused on the functionalization of Expancel beads by “grafting from” or “grafting onto” techniques. The first step consisted in reducing some nitrile functions at the surface into primary amine ones. After functionalization with bromoisobutyryl bromide, the SI-ATRP of acrylamide was performed in water at room temperature. On the other hand, the acryloyl chloride was grafted onto amine functions, and grafting of starch was achieved using a redox initiator. All materials obtained have been used for flocculation/flotation tests and demonstrated satisfactory performances in terms of turbidity removal. Beads functionalized with starch have been successfully regenerated with oxalic acid and sodium dithionite and kept appropriate efficiency during several flotation/regeneration cycles.

In the past decade there has been a growing interest in one-dimensional (1D) nanostructures, such as nanowires, nanotubes and nanorods, owing to their size-dependent optical and electronic properties and their potential application as building blocks, interconnects and functional components for assembling nanodevices. One of the ways to obtain such architectures is a template-directed synthesis which is practically a straightforward route to 1D nanostructures. In this approach, the template simply serves as a scaffold, within (or around) which a different material is generated in situ and shaped into a nanostructure with its morphology complementary to that of the template. It is generally accepted that template-directed synthesis provides a simple, high-throughput, and cost-effective procedure that also allows the complex topology present on the surface of a template to be duplicated in a single step. In the current work, utilization of the molecular bottle brushes as templates is proposed for the fabrication of conductive nanorods. Their non-spherical macromolecular geometries and lengths up to a few hundred nanometers allow the application of these structures in nanowire synthesis. The variety of molecular bottle brush architectures and their composition enables the adjustment of appropriate conditions for the preparation of conductive materials. Moreover, the ability of the brushes to assemble on a surface under certain conditions provides their usage as building blocks for the preparation of complex conductive networks. Here, the preparation, characterization, and applications of molecular bottle brushes are discussed. Two main goals were pursued. First, to deepen the knowledge in the synthesis of molecular bottle brushes, and to investigate their behavior on the surface. Second, to explore the application of the brushes as templates or building blocks for the formation of conductive nanowires. For the purpose, new ways of molecular brush synthesis by using the “grafting to” approach had to be developed. It was found that the reaction of nucleophilic addition based on pentofluorophenol chemistry and a coupling “click chemistry” reaction can be used to fabricate molecular brushes. Both methods showed efficient results and demonstrated high reactivity of the backbone with the end groups of the side chains. The “click chemistry” approach, however, demonstrated better results considering higher thicknesses of the brushes and, therefore, higher grafting density of the side chains. The “grafting to” together with the “grafting from” methods are very powerful synthetic tools, which can be used in the fabrication of any desired molecular bottle brush architectures. Additionally, complexation of oppositely charged bottle polymer brushes at a single-molecule level using AFM and CryoTEM was experimentally investigated. It was found that polyelectrolyte complexes have “scrambled-egg” morphology, where oppositely charged polymer chains are not oriented parallel to each other but cross each other. Furthermore, molecular bottle brushes were used as templates for the preparation of conductive nanowires. Three approaches for their fabrication were tested. It was found that brushes could easily be covered with various conductive materials, for example conductive polymers or metals. It was showed that for very small, tiny objects as molecular bottle brushes, one can use FIB in order to build up electrodes at its ends. The electrodes could be sputtered with an accuracy of 500 nm and further be used in the determination of the conductivity. The molecular bottle brushes covered with palladium showed the resistance of 50 MΩ, which, regarding the size of the brush, corresponds to a conductivity of one single molecule being ~1 S*cm-1. The obtained conductivity data were in good correlation with the data found in literature. We believe that the molecular bottle brushes have high potential applicability for the building of complex conductive networks. Future refinement of the synthetic methods, combined with improvements in structuring and positioning of objects at the nanoscale, could lead to their implementation in the construction of high-performance electronic devices.

Diese Dissertation beschreibt die Synthese und Charakterisierung neuartiger Hyperstern-Polymere (HSP) und deren Funktion als Reaktivbinder in Epoxy- bzw. PUR-Harzen. Hyperstern-Polymere sind Hybride aus hochverzweigten (hvz) und linearen Polymeren. Sie können über ihre reaktiven OH-Gruppen als multifunktionelle hochverzweigte Quervernetzer kovalent in ein kationisch härtendes Epoxyharz einbinden und thermische sowie thermomechanische Eigenschaften verbessern.

In the past decade there has been a growing interest in one-dimensional (1D) nanostructures, such as nanowires, nanotubes and nanorods, owing to their size-dependent optical and electronic properties and their potential application as building blocks, interconnects and functional components for assembling nanodevices. One of the ways to obtain such architectures is a template-directed synthesis which is practically a straightforward route to 1D nanostructures. In this approach, the template simply serves as a scaffold, within (or around) which a different material is generated in situ and shaped into a nanostructure with its morphology complementary to that of the template. It is generally accepted that template-directed synthesis provides a simple, high-throughput, and cost-effective procedure that also allows the complex topology present on the surface of a template to be duplicated in a single step. In the current work, utilization of the molecular bottle brushes as templates is proposed for the fabrication of conductive nanorods. Their non-spherical macromolecular geometries and lengths up to a few hundred nanometers allow the application of these structures in nanowire synthesis. The variety of molecular bottle brush architectures and their composition enables the adjustment of appropriate conditions for the preparation of conductive materials. Moreover, the ability of the brushes to assemble on a surface under certain conditions provides their usage as building blocks for the preparation of complex conductive networks. Here, the preparation, characterization, and applications of molecular bottle brushes are discussed. Two main goals were pursued. First, to deepen the knowledge in the synthesis of molecular bottle brushes, and to investigate their behavior on the surface. Second, to explore the application of the brushes as templates or building blocks for the formation of conductive nanowires. For the purpose, new ways of molecular brush synthesis by using the “grafting to” approach had to be developed. It was found that the reaction of nucleophilic addition based on pentofluorophenol chemistry and a coupling “click chemistry” reaction can be used to fabricate molecular brushes. Both methods showed efficient results and demonstrated high reactivity of the backbone with the end groups of the side chains. The “click chemistry” approach, however, demonstrated better results considering higher thicknesses of the brushes and, therefore, higher grafting density of the side chains. The “grafting to” together with the “grafting from” methods are very powerful synthetic tools, which can be used in the fabrication of any desired molecular bottle brush architectures. Additionally, complexation of oppositely charged bottle polymer brushes at a single-molecule level using AFM and CryoTEM was experimentally investigated. It was found that polyelectrolyte complexes have “scrambled-egg” morphology, where oppositely charged polymer chains are not oriented parallel to each other but cross each other. Furthermore, molecular bottle brushes were used as templates for the preparation of conductive nanowires. Three approaches for their fabrication were tested. It was found that brushes could easily be covered with various conductive materials, for example conductive polymers or metals. It was showed that for very small, tiny objects as molecular bottle brushes, one can use FIB in order to build up electrodes at its ends. The electrodes could be sputtered with an accuracy of 500 nm and further be used in the determination of the conductivity. The molecular bottle brushes covered with palladium showed the resistance of 50 MΩ, which, regarding the size of the brush, corresponds to a conductivity of one single molecule being ~1 S*cm-1. The obtained conductivity data were in good correlation with the data found in literature. We believe that the molecular bottle brushes have high potential applicability for the building of complex conductive networks. Future refinement of the synthetic methods, combined with improvements in structuring and positioning of objects at the nanoscale, could lead to their implementation in the construction of high-performance electronic devices.

Diese Dissertation beschreibt die Synthese und Charakterisierung neuartiger Hyperstern-Polymere (HSP) und deren Funktion als Reaktivbinder in Epoxy- bzw. PUR-Harzen. Hyperstern-Polymere sind Hybride aus hochverzweigten (hvz) und linearen Polymeren. Sie können über ihre reaktiven OH-Gruppen als multifunktionelle hochverzweigte Quervernetzer kovalent in ein kationisch härtendes Epoxyharz einbinden und thermische sowie thermomechanische Eigenschaften verbessern.:Theoretischer Teil Einleitung und Aufgabenstellung Grundlagen 1 Polymeraufbau 1.1. Radikalische Polymerisationen 1.1.1. Kontrolliert radikalische Polymerisation 1.1.2. NMRP 1.1.3. ATRP 1.1.4. RAFT 1.2. Anionische Polymerisation 1.3. Kationische Polymerisation 1.3.1. CROP von Oxazolinen 1.4. Koordinative Polymerisationen 2 Verzweigte Polymerarchitekturen 2.1. Dendritische Polymere 2.1.1. Dendrimere 2.1.2. Hochverzweigte Polymere 2.1.2.1 SCVP 2.1.3. Dendrigrafts 2.1.4. Dendronisierte Polymere 2.2. Spezielle Polymerarchitekturen 2.2.1. Hyperstern-Polymere (HSP) 3 Lacke 3.1. Lösungsmittelhaltige Lacke 3.1.1. Chemisch härtende Lacke 3.1.2. Physikalisch trocknende Lacke 3.2. Wässrige Lacke 3.3. Lösungsmittelfreie Lacke 3.3.1. Strahlenhärtende Lacke 3.3.2. Pulverlacke 3.4. Aliphatische Epoxylacke 3.4.1. UV-Härtung 3.4.2. Thermische Härtung 3.4.3. Thermische Härtung klassischer 2K-Polyepoxid-Lacke 3.5. 2K-PUR-Lacke 3.6. Aktuelle Herausforderungen 3.7. Wissenschaftliche Konzepte zur Schlagzähmodifizierung von Lacken Diskussion und Ergebnisse 4 Synthese hochverzweigter Makroinitiatoren 4.1. Polyester-Makroinitiatoren PE-MI1 und PE-MI2 4.1.1. Polyester-Kern (PE-OH) 4.1.2. Makroinitiatoren für die Oxazolinpolymerisation (PE-MI1) 4.1.3. Makroinitiatoren für die ATRP von Methacrylaten (PE-MI2) 4.2. Poly(vinylbenzylchlorid)-Makroinitiator (PVBC) 5 Hypersterne mit POxa-Armen 5.1. Lineare Polyoxazolin-Modellverbindungen (POxa) 5.1.1. Test der Initiatorfunktionen 5.1.2. Einfluss der Mikrowelle 5.1.3. Terminierung (Capping) 5.1.4. Polymerisation OH-tragender Oxazoline 5.1.5. Adamantan-funktionalisierte Polyoxazoline 5.2. Hypersterne aus Polyester-Kern sowie Polyoxazolin-Armen: PE-g-POxa 5.2.1. Einführung von OH-Gruppen über die Terminierung 5.2.2. Einführung von OH-Gruppen über die Wiederholeinheiten 5.3. Hypersterne aus Polyvinylbenzylchlorid-Kern sowie Polyoxazolin-Armen: PVBC-g-POxa 5.3.1. Modellinitiatoren 5.3.2. Einführung von OH-Gruppen über die Wiederholeinheiten 5.4. Ausblick: Arm first-Strategie 6 Hypersterne mit Polymethacrylat-Armen 6.1. Hypersterne aus Polyvinylbenzylchlorid-Kern sowie Polymethacrylat-Armen: PVBC-g-PHEMA 6.2. Hypersterne aus Polyester-Kern sowie Polymethacrylat-Armen: PE-g-(PMMA-b-HEMA) 7 Hypersterne als Quervernetzer-Additive in Lacken 7.1. PVBC-g-POxa in Epoxyharz 7.1.1. Thermische Härtung 7.2. PE-g-P(MMA-b-HEMA) in Epoxyharz 7.2.1. UV-Härtung 7.2.2. Thermische Härtung 7.3. PE-g-P(MMA-b-HEMA) in 2K-PUR-Harz Zusammenfassung – Ausblick Experimenteller Teil 8 Geräte, Methoden und Chemikalien 9 Synthesen 9.1. Monomere, Capper, Niedermolekulare Substanzen 9.2. Lineare Polyoxazoline 9.2.1. Niedermolekulare CROP-Initiatoren 9.2.2. Lineares Poly(2-methyloxazolin) (PMeOxa) 9.2.3. Adamantan-funktionalisierte Poly(2-methyloxazoline) 9.2.4. Lineare Poly(2-ethyloxazoline) 9.2.5. NMR-Modellverbindungen für PVBC-Kern 9.3. Hochverzweigte Polymere und Makroinitiatoren 9.4. Hyperstern-Polymere mit POxa-Armen 9.5. Hyperstern-Polymere mit PAlkMA-Armen 9.6. Lackproben Abkürzungsverzeichnis Literaturverzeichnis Publikationsliste

Surface-initiated photo-iniferter mediated controlled polymerisation was used as a technique for the development of advanced and smart materials. Molecularly imprinted polymer (MIP) shell nanoparticles (NPs) were synthesised in this way from PAMAM dendrimers, used as a graftable core, in 2 min irradiation time. Surprisingly the so-synthetised NPs were around 200 nm and had a cubic shape. Cont/d.

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