This thesis reports the fabrication of nanophotonic structures by using electron beam lithography and using pattern transfer via self assembly with the aid of block copolymers. A theoretical and experimental basis was developed for fabricating anti-reflective coatings using block-copolymer pattern transfer. Block-copolymers were also used to fabricate plasmonic pattern arrays which form gold dots on glass surface. Electron-beam lithography was utilized to fabricate holey plasmonic structures from gold and silver films. Electron-beam exposure was used in block-copolymer lithography in selected regions. The exposure effects were studied for both thin and thick block-copolymer films. Reactive and ion beam etching techniques were used and optimized to fabricate those structures. This research required a great deal of development of new fabrication methods and key information is included in the body of the thesis.

Well-defined heterobifunctional homopolyethers and amphiphilic block copolyethers containing a variety of functionalities were designed, synthesized, and characterized via GPC and 1H NMR. These have included controlled molecular weight cholesterol-PEO-OH, mono- and trivinylsilyl-PEO-OH, monovinylsilyl-PEO-PPO-OH, monovinylsilyl-PEO-PPO-PEO-OH, maleimide-PEO-OH, stearyl alcohol-PEO-OH, propargyl alcohol-PEO-OH, trivinylsilyl-PPO-OH, trivinylsilyl-PPO-PEO-OH, and benzyl alcohol-initiated poly(allyl glycidyl ether)-OH. The focus of polymers utilized in this study involved the mono- and trivinylsilyl polyethers. The vinylsilyl endgroups on these materials were functionalized with various bifunctional thiols through free radical addition of SH groups across the vinylsilyl double bonds. The resultant end-functional polyethers were adsorbed onto magnetite nanoparticles and the stabilities of the polymer-magnetite complexes were compared as a function of the type of anchoring moiety and the number of anchoring moieties per chain. Anchoring chemistries investigated in this work included carboxylates, alkylammonium ions, and zwitterionic phosphonates. The anchor group-magnetite bond stability was investigated in water and phosphate buffered saline (PBS). Through these studies, the zwitterionic phosphonate group was shown to be a better anchoring group for magnetite than either carboxylate or ammonium ions. Tri-zwitterionic phosphonate anchor groups provided stability of the complexes in PBS for a broad range of polymer loadings. Thus, investigations into the stability of polyether-magnetite complexes in PBS focused on hydrophilic zwitterionic phosphonate-PEO-OH and amphiphilic zwitterionic phosphonate-PPO-b-PEO-OH oligomer coatings on the surface of magnetite. Superparamagnetic magnetite nanoparticles are of interest as potential contrast-enhancement agents for MRI imaging. Thus, transverse NMR relaxivities of these complexes were studied as a function of chemical composition and nanostructure size and compared to commercial contrast agents. The amphiphilic polyether-magnetite nanoparticles were shown to be stable in both aqueous media as well as physiological media and have much higher transverse relaxation values, r2, than those of commercial contrast agents and other materials in the literature. / Ph. D.

[pt] O presente estudo investiga a estrutura e a potencial aplicação de nanopartículas formadas por copolímeros que possuem um bloco neutro e outro bloco aniônico combinados a um surfactante catiônico. Em água, os blocos aniônicos se complexam eletrostaticamente às micelas de surfactante, interconectando-as e formando um núcleo concentrado, que pode até apresentar estrutura líquido-cristalina. Os blocos neutros são hidrofílicos e por isso formam uma casca que estabiliza as nanopartículas em água. Devido à formação do núcleo concentrado de micelas, espera-se que estas nanopartículas sejam capazes de incorporar uma maior quantidade de moléculas hidrofóbicas em comparação a micelas de surfactante puro na mesma concentração. Os resultados indicam que quanto mais longo é o bloco aniônico, mais alta é a incorporação das moléculas hidrofóbicas. Por outro lado, o bloco neutro tem um papel importante para aumentar a estabilidade das nanopartículas em meio aquoso. A incorporação de moléculas hidrofóbicas no núcleo das nanopartículas causa alterações na organização das micelas, levando à formação de diferentes estruturas líquido-cristalinas ou a alterações nas distâncias de correlação. Com base nas propriedades das nanopartículas, foi proposta uma formulação aquosa capaz de incorporar uma quantidade significativa de um filtro solar orgânico. Com os resultados obtidos para esta formulação, foi possível demonstrar sua eficácia em evitar a degradação de cabelos por irradiação ultravioleta, o que torna este sistema um candidato de alto potencial para aplicação na indústria de cosméticos. / [en] The present study investigates the structure and potential application of core-shell nanoparticles formed by block copolymers (consisted of an anionic and a neutral blocks) and a cationic surfactant. In water, the anionic blocks electrostatically complex to the surfactant micelles, interconnecting them and forming a concentrated nucleus, which may form even liquid-crystalline structures. Because the neutral blocks are hydrophilic, they form a shell which stabilizes the nanoparticles in water. The concentrated nuclei of micelles are expected to uptake a higher amount of hydrophobic molecules than the regular micelles of pure surfactant in the same concentration. The longer is the anionic block forming the nucleus, the higher is the uptake of hydrophobic substances. On the other hand, the neutral block plays a key role to increase nanoparticle stability in aqueous medium. The uptake of hydrophobic molecules increased the ordering of the micelles in the nucleus, leading either to the formation of different liquid-crystalline structures or to variations in the correlation distances. Taking these results in to account, we proposed an aqueous formulation with a considerable uptake capacity of an organic sunscreen. The results obtained for this formulation demonstrate its efficacy to avoid hair degradation by ultraviolet radiation exposition, which make this system a potential candidate for applications in the cosmetic industry.

In this thesis detailed investigations of the phase behavior of poly(n-alkyl methacrylate-b-methyl methacrylate) diblock copolymers and its influence on the wettability of the polymer surfaces were carried out. For this investigation two polymethacrylic systems differing only in the alkyl rest of one block: poly(pentyl methacrylate-b-methyl methacrylate) and poly(propyl methacrylate-b-methyl methacrylate) have been chosen in order to prove how this substituent affects the phase behavior of whole system. The PnAlkMA-b-PMMA diblock copolymers in a wide range of molar masses, and with varied block length ratios were synthesized by living anionic polymerization. The syntheses were carried out in tetrahydrofuran (THF), at –78 °C, by using sec-buthyllithium as initiator, in the presence of lithium chloride (LiCl). Under these conditions highly syndiotactic products, rr ~ 0.82, with very narrow molar mass distribution, Mw/Mn ~ 1.1, were obtained. The phase behavior of PnAlkMA-b-PMMA diblock copolymers in bulk was investigated by means of DSC and SAXS measurements. The DSC analysis revealed that the PPMA-b-PMMA with weight fractions of PPMA, fPPMA, from 0.28 up to 0.86 showed two separate Tg’s, indicative of a phase separated system. However, by comparing the Tg’s of the diblock copolymers with the Tg’s of the corresponding homopolymers we found that in a few cases, mostly for samples with the high molar masses, they were slightly shifted. This finding pointed out the existence of two mixed phases, and hence partial miscibility between the both blocks was assumed. The SAXS patterns reflected for most diblock copolymers lamellae morphologies even in the case of very asymmetric composition, for instance with volume fraction of PPMA, 0.86 It was assumed that this behavior is caused by the chemical similarity of both blocks as well as by the differences in their molar volumes. The SAXS findings were further confirmed by the AFM measurements on the cutted “bulk” samples. From the solubility concept of Van Krevelen we obtained that the interaction parameter of PPMA-b-PMMA is rather low, 0.065, compared to the other well-known diblock copolymers. The calculated spinodals are characterized by a high asymmetry. The investigation of the phase behavior of PPMA-b-PMMA in thin films showed that the morphology as well as the topography of the thin films were strongly affected by the film thickness, when the films were prepared from a non-selective solvent (THF) onto silicon wafers. Well-recognizable nanostructures with long-range order were mainly found in thin films of diblock copolymers with high molar masses, above 100,000 g/mol, and with a high amount of PPMA. The lateral domain spacing obtained for these films from AFM corresponded well with that found in bulk. The study of the influence of the thermal as well as vapor annealing on the morphology and topography of the thin films provided additional information about the phase behavior of PPMA-b-PMMA diblock copolymers in thin films. Finally, the wettability of the investigated PPMA-b-PMMA surfaces was established by means of contact angle measurements. The measured contact angles were in most cases even on nicely nanostructured surfaces very similar to the contact angle of PPMA, indicating preferential segregation of PPMA to the film surface. Additional XPS measurements also showed an enrichment of the PPMA at the surface, independent of the morphology observed by AFM, and thereby confirmed the ADSA finding. In the next part of this work, investigations of the phase behavior of PPrMA-b-PMMA diblock copolymers were presented. In the contrary to the previous system the PPrMA-b-PMMA showed mostly a single Tg, which was further found to be depend on the weight fraction of PPrMA, fPPrMA. The SAXS data revealed that the PPrMA-b-PMMA diblock copolymers were phase separated in bulk, however the obtained scattering patterns exhibited mostly broad, not-well discernible higher-order peaks. Nevertheless, it was possible to identify the formed morphologies and depending on the volume fraction of PPrMA, hexagonally packed cylinders and lamellae were detected. The PPrMA-b-PMMA is characterized by a significantly lower value of the interaction parameter, 0.022, than the PPMA-b-PMMA system. This difference clearly reflects the weakening of the interactions between the components with decrease of the length of the alkyl side chain. The thin films of PPrMA-b-PMMA diblock copolymers appeared mostly smooth and featureless, independent of the film thickness. From the contact angle and XPS measurements we obtained, that unlike the PPMA-b-PMMA, both components were always present on the top of the surface. / In der vorliegenden Arbeit wurden Untersuchungen zum Entmischungsverhalten von Poly(n-alkylmethacrylat-b-methylmethacrylat) Diblockcopolymeren und deren Einfluss auf die Benetzbarkeit der Polymeroberflächen dargestellt. Diese Untersuchungen wurden anhand der Poly(pentylmethacrylat-b-methylmethacrylat) und Poly(propylmethacrylat-b-methylmethacrylat) durchgeführt. Die Diblockcopolymere in einem weiten Molmassenbereich, mit enger Molmassenverteilung, abgestuften Zusammensetzung wurden erfolgreich mittels anionischer Polymerization synthetisiert. Die Synthese erfolgte in THF bei (-78 °C) in Gegenwart von Lithiumchlorid. Als Initiator wurde sec. Butyllithium genutzt. Das Phasenverhalten der Diblockcopolymere im Festkörper wurde mittels DSC und SAXS untersucht. Für die meiste PPMA-b-PMMA Diblockcopolymere wurden mittels DSC zwei getrennte Tg gefunden, die aber im Vergleich zu den Tg von den entsprechenden Homopolymeren leicht verschoben waren. Es wurde also eine partielle Mischbarkeit der Blöcke festgestellt. Mittels SAXS-Untersuchungen wurde für die Mehrzahl der Diblckcopolymere in einem weiten Zusammensetzungsbereich bis zum 0.86 Volumenanteil von PPMA, eine lamellare Anordnung beobachten. Diese Befunde wurden nachfolgend mit AFM–Untersuchungen an dünnen Polymerfolien bestätigt. Das mit der Mean-Filed-Methode berechnete Phasendiagramm zeigte eine Asymmetrie, die durch die Unterschiede in den molaren Volumina des Blöckes verursacht war. Es wurde aber eine gute Übereinstimmung mit der experimentell erhaltenen Daten gefunden. Der berechnete für das System Wechselwirkungsparameter beträgt 0,065. Die AFM-Untersuchungen zum Entmischungsverhalten in dünnen Filmen haben gezeigt, dass die Topographie als auch Morphologie des Films war von der Filmdicke beeinflusst. Die Polymerfilme wurden mittels dipcoating der Si-Wafer präpariert. Dazu wurden Polymerlösungen in THF verwendet. Reguläre Nanostrukturen, deren Abstände mit dem im Festkörper gefundenen sehr gut übereinstimmten, wurden bei den Proben mit höherem Anteil von PPMA erhalten. Es wurden auch der Einfluss der Temperatur und der Dampfbehandlung auf die Morphologie und Topographie des Films untersucht. Die Benetzbarkeit der untersuchte PPMA-b-PMMA Filme wurde mit der Kontaktwinkelmessungen (ADSA) bestimmt. Als Messflüssigkeit wurde Milipore Wasser genutzt. Für die Mehrzahl der Diblockcopolymere wurden Kontaktwinkel im Bereich um 95° ermitteln, unabhängig von der Zusammensetzung der Diblockcopolymere und der vorhandenen Nanostruktur. Dies entspricht dem Kontaktwinkel von PPMA Homopolymer. Die Benetzbarkeit der PPMA-b-PMMA Filme wurde also durch die Oberflächensegregation des Niedrigenergieblocks (PPMA) bestimmt. Dies wurde danach durch zusätzliche XPS Messungen bestätigt. Im Vergleich zu PPMA-b-PMMA, die nachfolgend untersuchte PPrMA-b-PMMA Diblockcopolymere wiesen eine höhere Tendenz zur Mischbarkeit auf. Anhand der DSC–Untersuchungen wurde hier vorübergehend eine Misch-Tg gefunden. Nur bei der Probe mit symmetrischer Zusammensetzung wurden zwei getrennte Tg beobachtet. Die Streukurven von diesem System waren sehr schwach ausgeprägt. Dadurch die Indizierung der vorhandenen Morphologien war nicht eindeutlich. Der berechnete Wechselwirkungsparameter beträgt 0,022. Bei den AFM-Untersuchungen zum Entmischungsverhalten in dünnen PPrMA-b-PMMA Filmen wurden entweder keine oder sehr schwach geordnete Nanostruktur gefunden. Im Gegensatz zu dem vorherigen System, die Benetzbarkeit der PPrMA-b-PMMA Filme war durch die Zusammensetzung der Diblockcopolymere bedingt.

L’objectif de cette thèse est d’étudier la synthèse et les propriétés d’auto-assemblage en milieu aqueux de copolymères « intelligents » capables de former des agrégats supramoléculaires en réponse à deux stimuli : la température du milieu et la présence de dioxyde de carbone (CO2). Pour cela, une gamme de copolymères diblocs amphiphiles composés d’un bloc hydrophile d’acrylate de polyethylèneglycol méthyléther) (PEGA) et d’un bloc stimulable contenant une distribution statistique d’unités PEGA et acrylate de diéthlèneglycol éthyléther (DEGA) (thermosensibles) et acrylate de diéthylaminoéthyle DEAEA (CO2-sensible), a été préparée par polymérisation radicalaire contrôlée par les nitroxydes (NMP). Dans un second temps, il a été mis en évidence que la température ainsi que la présence de CO2 dans la solution influencent le comportement auto-associatif des copolymères dans l’eau. Par la suite, le bloc hydrophile a été remplacé par une séquence de dextrane, ce qui a permis de préparer de nouveaux copolymères diblocs fonctionnels, stimulables par la température et le CO2. Dans ce cas, deux techniques de polymérisation radicalaire contrôlée (NMP et ATRP) ont été testées afin d’obtenir les copolymères possédant l’architecture la mieux définie possible. / This project aims to investigate the synthesis and properties of dual stimuli-responsive block copolymers able to self-assemble into supramolecular aggregates in response to two stimuli: the temperature and the presence of carbon dioxide in the aqueous solution. Therefore, a range of amphiphilic diblock copolymers composed of a hydrophilic block of polyethylene glycol methylether acrylate (PEGA) and a statistical block of PEGA, diethylene glycol ethyl ether acrylate (DEGA) and diethylaminoethyl acrylate (DEAEA) was prepared via nitroxide-mediated polymerization (NMP) and the level of control of each synthesis was studied. We evidenced that temperature and CO2 play a different role in the self-assembly of such block copolymers. Finally, the introduction of dextrane as hydrophilic block coming from renewable resources allows for the preparation of novel “smart” amphiphilic diblock copolymers. In order to synthesize these block copolymers with well-defined structure, both NMP and atom transfer radical polymerization (ATRP) were investigated in parallel.

Le domaine des nanotechnologies représente la thématique de recherche la plus importante de ce début de 21ème siècle. L’enjeu, bien que apparemment simple est de taille : réaliser des objets ou des structures fonctionnelles, les plus petits possibles et ce de manière reproductible, i.e. en maîtrisant leur taille, leur position. S’inscrivant dans cette problématique, ce travail de thèse porte sur le développement d’une technique originale d’assemblage dirigé de nanostructures à partir de particules d’or et d’argent sous forme de nanofils, nanocristaux, nanoanneaux et nanodisques sur des substrats rigides. Cette technique s’appuie sur une méthode purement chimique reconnue et basée sur la réduction colloïdale in situ de sels métalliques sur une surface. L’organisation bi ou tridimensionnelle de ces nanoparticules métalliques est, de plus, induite par une préstructuration du substrat réalisée par le dépôt d’un film mince de copolymères diblocs. En effet, l’auto-assemblage de films minces de copolymère permet de réaliser, par micro-séparation de phase à la paroi, un réseau bidimensionnel hexagonal de cylindres verticaux. La suppression d’une des phases du système permet de générer alors un film organique nanoporeux organisé sur le substrat qui va servir de masque et permettre d’assembler des nanoparticules métalliques lors d’une seconde étape. L’initiation du dépôt de nanoparticules métalliques dans les pores du masque a été réalisée sous ultravide en épitaxie par jets moléculaires ou par voie colloïdale en solution. La croissance finale (complète) des cristaux métalliques d’argent a été poursuivie enfin par voie colloïdale en solution. Les propriétés spectroscopiques, de mouillage et électrochimiques des structures nanoparticulaires étudiées dans ce travail ont été directement corrélées aux morphologies cristallines de surface. Une des perspectives de ce travail préliminaire est el développement d’une plateforme MEMS générique pour la détection de traces de plusieurs types de molécules (volatiles et réfractaires) par voie électrochimique. / Nanotechnology became one of the most important research field of the 21st century. Though seemingly simple, the challenge is huge: achieving the formation of the smallest objects or functional structures (in a reproducible manner) and being able to control acurately their sizes and positions, as well. Answering these demands, this thesis deals with the development of a novel technique focusing on the directed growth and assembly of metallic nanostructures onto rigid substrates. First, the combination of phase separation of a block copolymer leading to the formation of nanopores, and gold nanocolloids synthesis confined in the nanoholes, has allowed the facile fabrication of hexagonally arranged gold nanoparticles onto silicon wafer. Then, the in situ reduction of colloidal silver salts has lead to the selective growth of metallic crystals onto the rigid prepatterned substrate. The control of both the physical parameters of the patterning and the chemical synthesis ones has induced the formation of various microstructures metallic morphologies ranging from nanowires, nanocrystals, nanorings and nanodisks. Spectroscopic properties, wetting and electrochemical these nanoparticles structures were finally investigated and directly correlated with crystal surface morphologies. One of the perspectives of this preliminary work is the development of a MEMS generic platform allowing the electrochemical detection of trace of molecules (volatile or refractory).

In the present work, we have undertaken a structural study of PS-b-PEO single crystals to elucidate the influence of the state of the PS block on crystallization from dilute solution and on subsequent thermal annealing at elevated temperature. It is noteworthy that the interest in these systems has been recently renewed in the perspective of using them as a model of grafted amorphous brushes with variable grafting density. Indeed, during crystallization of PEO, the amorphous block, i.e. PS, is rejected from the crystal accumulating on its basal surfaces. Since the crystal thickness formed during isothermal crystallization is a sharply selected value, the grafting density of the resulting PS brush is also well defined. Therefore by varying the crystal thickness one can obtain the PS brushes with grafting density varying in a broad range.In our study, a combination of reciprocal and direct-space techniques such as SAXS/WAXS and AFM was employed. While AFM experiments were performed on isolated single crystals, the SAXS investigation was carried out on oriented mats of single crystals slowly sedimented from the "mother" solution. In this case, the one-dimensional two-phase system model was used for the data interpretation where the thickness of the amorphous (La) and crystalline (Lc) layers are conventionally determined following the correlation fonction and interface distribution fonction approaches.

Block copolymer (BCP) thin film patterns, generated using directed self-assembly (DSA) of diblock copolymers, have shown excellent promise as templates for semiconductor device manufacturing since they have the potential to produce feature pitches and sizes well below 20 nm and 10 nm, respectively, using current 193 nm optical lithography. The goal of this work is to explore block copolymers with sufficient thermodynamics driving force (as described by the Flory Huggins interaction parameter, χ) for phase separation at these smallest lengths scales. Here, poly(styrene)-b-poly(hydroxystyrene) is investigated since the PHOST domain is known to form extensive hydrogen bond networks resulting in increased χ due to this strong enthalpic interaction. In this work, nitroxide mediated polymerization (NMP) techniques were utilized to produce PS-b-PHOST diblock copolymers with a range of molecular weights (5000-30000) with low PDI approaching 1.2. The phase separation of low molecular weight PS-b-PHOST on neutral underlayer substrates via solvent annealing provided thin film vertical lamellae with 13 nm pitch. These results illustrate the improved resolution of PS-b-PHOST compared with the current industry standard of PS-b-PMMA (with 20 nm pitch). The directed self assembly of lamellar PS-b-PHOST patterns with 18 nm pitch via graphoepitaxy is demonstrated. Also, a highly selective atomic layer deposition (ALD) and etch technique was investigated which provided selective block removal of (PS-b-PHOST) block copolymer patterns which initially exhibited no inherent etch contrast. In this process, the PS domain is removed leaving a high fidelity etch relief pattern of the original block copolymer template. Finally, an alternative system is presented, namely Poly(trimethylsilylstyrene)-block-poly(hydroxystyrene) (PTMSS-b-PHOST), which utilizes silicon containing functionality in one of the blocks, providing high etch contrast. PTMSS-b-PHOST patterns were also exposed to oxygen plasma allowing selective block removal of the PS domain without the need for additional ALD processing steps.

La Résonance Magnétique Nucléaire RMN DOSY (Diffusion Ordered SpectroscopY) 1H est une technique permettant de mesurer les coefficients de diffusion des espèces en solution. Elle permet ainsi d’obtenir des informations structurales de par sa dimension RMN conventionnelle mais également des informations physico-chimiques telles que la taille de la (macro)molécule ou encore la formation d’agrégats. L’objectif de ces travaux a été d’examiner comment les méthodes de RMN (RMN 1D ,2D et DOSY), permettent de fournir des informations sur la caractérisation des matériaux polymères. La première partie de ce travail souligne l’intérêt de la RMN pour la caractérisation de la microstructure de quelques matériaux polymères en s’attardant plus particulièrement sur l’exploration de leurs extrémités de chaînes. La RMN s’est en effet révélée très performante pour établir le lien entre extrémité de chaîne et méthode de polymérisation appliquée. Le deuxième volet de ces travaux concerne l’étude de quelques architectures complexes (type dibloc et tribloc) et la mise en évidence du caractère contrôlé d’une copolymérisation radicalaire grâce à la RMN diffusionnelle. Nous avons également vu comment déterminer la masse moyenne en poids (Mw) par une simple mesure du coefficient d’autodiffusion. Finalement, l’ensemble des travaux présentés dans ce manuscrit a été valorisé grâce à l’étude des interactions par RMN diffusionnelle. Plus particulièrement la RMN DOSY 1H a permis d’observer des phénomènes de micellisation, d’agrégation, d’encapsulation et de relargage de molécules de principe actif. / Diffusion Ordered Spectroscopic Nuclear Magnetic Resonance (DOSY NMR 1H) makes it possible to determine physicochemical data such diffusion coefficients. While typical NMR data on the structure of molecules can be obtained, this technique also permits determinations of the physicochemical characteristics, such as molecular sizes or aggregate formation. The objective of this work was to examine how various NMR methodologies, specifically, 1 and 2 dimensional DOSY NMR, can be applied to the characterization of polymers. The first part of the manuscript relates the NMR characterization of some polymeric materials with a special interest in chain-end groups. In particular, we demonstrate the relationships between chain-ends and the polymerization methods employed. In a second part, the potential of the DOSY technique is used to determine controlled features of a radical polymerization resulting in di- and triblock architectures. Molecular weights are also determined by self-diffusion coefficient measurements. The results presented herein demonstrate that diffusional NMR can be effectively employed to understand interactions in polymeric structures. Indeed, DOSY 1H-NMR provides new interesting results concerning micellization, aggregation, encapsulation phenomena and the release of active molecules.

Ce travail concerne la modification de surface de nanoparticules magnétiques (MNP) par des copolymères réactifs renfermant des cycles azlactone, aux fins de l’élaboration de nano-supports destinés à l’immobilisation de biomolécules. Trois stratégies basées sur des techniques de polymérisation radicalaire contrôlée ont été mises en œuvre.Dans la première, un copolymère poly(méthacrylate de poly(éthylène glycol)-stat-2-vinyl-4,4-diméthylazlactone) (poly(PEGMA-stat-VDM)) a été préparé par polymérisation radicalaire par transfert d’atome (ATRP) selon la technique « grafting from » à partir des MNP et utilisé pour la bioconjugaison de thymine peptide nucleic acid (PNA). La présence de l’écorce polymère et l’immobilisation du PNA ont été confirmées par différentes techniques complémentaires (FTIR, VSM).La deuxième stratégie est basée sur l’élaboration de MNP greffées pour la bioconjugaison de l’acide folique, via l’ARTP du PEGMA et de la VDM. L’analyse par microscopie électronique à transmission (TEM) a montré qu’après bioconjugaison les MNP possèdent une très bonne aptitude à la dispersion en milieu aqueux.La troisième stratégie met en œuvre la technique «grafting onto » de copolymères poly(oxyde d’éthylène)-bloc-poly(2-vinyl-4,4-dimethylazlactone) (PEO-b-PVDM) pour la préparation de nanosupports magnétiques recyclables. Des copolymères à blocs PEO-b-PVDM ont été préparés par la technique de polymérisation RAFT puis greffés sur des MNP fonctionnalisées amino-silane. Les analyses en TEM et par spectroscopie de corrélation de photons ont révélé l’aptitude à la dispersion aqueuse et à la formation de nanoclusters. Les clusters ainsi obtenus ont été utilisés en tant que nanosupports magnétiques recyclables pour l’adsorption d’anticorps. / We herein report the surface modification of magnetite nanoparticle (MNP) with copolymers containing active azlactone rings via a grafting ‘from’ and grafting ‘onto’ controlled radical polymerization (CRP) for use as a nano-solid support for immobilization with biomolecules. Three different approaches were presented as following. First, synthesis of poly(poly(ethylene glycol) methyl ether methacrylate-stat-2-vinyl-4,4-dimethylazlactone) (PEGMA-stat-VDM)-grafted MNP via a grafting ‘from’ atom transfer radical polymerization (ATRP) and its application as a platform for conjugating thymine peptide nucleic acid (PNA) monomer were presented. The presence of polymeric shell and the immobilization of thymine PNA on MNP core were confirmed by fourier transform infrared spectroscopy (FTIR) and vibrating sample magnetometry (VSM) techniques. The second strategy is based on the synthesis of MNP grafted with PEGMA and VDM via ATRP for conjugation with folic acid (FA). The existence of PEGMA and VDM in the structure was characterized by FTIR, TGA and VSM. After the FA conjugation, Transmission Electron Microscopy (TEM) results indicated that the FA-conjugated MNP having high VDM content exhibited good dispersibility in water.Third, the synthesis of MNP grafted with poly(ethylene oxide)-block-poly(2-vinyl-4,4-dimethylazlactone) (PEO-b-PVDM) block copolymer via a grafting ‘onto’ strategy and its application as recyclable magnetic nano-support for adsorption with antibody were studied. PEO-b-PVDM diblock copolymers were first synthesized using reversible addition-fragmentation chain transfer (RAFT) polymerization and then grafted onto amino-functionalized MNP. TEM images and photo correlation spectroscopy (PCS) indicated an improvement in the particle dispersibility in water after coating with the copolymers. The nanoclusters with PEO-b-PVDM copolymer coating were used as recyclable magnetic nano-supports for adsorption with antibody.