Hydrophilic/hydrophobic block copolymers as proton exchange membranes (PEMs) has become an emerging area of research in recent years. Three series of hydrophilic/hydrophobic, fluorinated/sulfonated multiblock copolymers were synthesized and characterized in this thesis. These copolymers were obtained through moderate temperature (~100°C) coupling reactions, which minimize the ether-ether interchanges between hydrophobic and hydrophilic telechelic oligomers via a nucleophilic aromatic substitution mechanism. The hydrophilic blocks were based on the nucleophilic step polymerization of 3,3′-disulfonated, 4,4′-dichlorodiphenyl sulfone with an excess 4,4′-biphenol to afford phenoxide endgroups. The hydrophobic (fluorinated) blocks were largely based on decafluoro biphenyl (excess) and various bisphenols. The copolymers were obtained in high molecular weights and were solvent cast into tough membranes, which had nanophase separated hydrophilic and hydrophobic regions. The performance and structure-property relationships of these materials were studied and compared to random copolymer systems. NMR results supported that the multiblock sequence had been achieved. They displayed superior proton conductivity, due to the ionic proton conducting channels formed through the self-assembly of the sulfonated blocks. The nano-phase separated morphologies of the copolymer membranes were studied and confirmed by atomic force microscopy. Through control of a variety of parameters, including ion exchange capacity and sequence lengths, performances as high, or even higher than those of the state-of-the-art PEM, Nafion, were achieved. / Ph. D.

Le lien entre la structure semi-cristalline et les propriétés d’usage (mécaniques, diélectriques et électro-actives) de films de copolymères fluorés électro-actifs développés pour des applications en électronique organique imprimée a été étudié. Les matériaux investigués sont des copolymères poly(VDF-co-TrFE) et des terpolymères poly(VDF-ter-TrFE-ter-CTFE) à base de fluorure de vinylidène (VDF), trifluoroéthylène (TrFE) et chlorotrifluoroéthylène (CTFE).Les films de polymères obtenus par évaporation du solvant sont étudiés par diffraction des rayons X (SAXS-WAXS), DSC, FTIR, DMA, spectroscopie diélectrique et cycles de polarisation afin de mettre en évidence l’impact de la composition et de la mise en forme (recuit, polarisation) sur la structure et les propriétés finales du matériau. Nous montrons ainsi qu’au sein des films de copolymères, la phase ferroélectrique (FE) coexiste avec une phase ferroélectrique défective (DFE). La fraction croissante de cette phase DFE avec la teneur en TrFE permet d’expliquer l’évolution des propriétés thermiques dont la transition de Curie. Une transition structurale continue, de la phase DFE vers la phase paraélectrique (PE), en température a été mise en évidence.La teneur en termonomère CTFE influence fortement la structure cristalline et les propriétés électro-actives des films de terpolymères (disparition du caractère ferroélectrique au profit du caractère ferroélectrique relaxeur (RFE)). Nous prouvons pour la première fois l’existence d’une transition structurale continue entre la phase RFE et la phase PE au voisinage de la température ambiante. Cette transition permet d’expliquer les propriétés exacerbées de ces matériaux (constante diélectrique et déformation sous champ électrique). Enfin, des analogies de comportement entre les copolymères et les terpolymères sont discutées, notamment l’évolution des phases cristallines sous champ électrique, afin de mieux comprendre le fonctionnement de ces polymères électro-actifs pour leur futur développement au niveau industriel. / The relationship between semi-crystalline structure and properties of use (mechanical, dielectric and electroactive) of fluorinated copolymer films was studied for applications in organic electronics. Investigated materials are poly(VDF-co-TrFE) copolymers and poly(VDF-ter-TrFE-ter-CTFE) terpolymers based on vinylidene fluoride (TrFE), trifluoroethylene (TrFE) and chlorotrifluoroethylene (CTFE). Polymer films, obtained after solvent evaporation, are studied by X-ray diffraction (SAXS-WAXS), DSC, FTIR, DMA, dielectric spectroscopy and polarization cycles in order to highlight the impact of composition and processing (annealing, poling) on structure and final properties of material. We showed that the ferroelectric (FE) phase coexists with the defective ferroelectric (DFE) phase in copolymer films. The increasing fraction of DFE phase with TrFE content allows explaining the evolution of thermal properties. A continuous structural transition, from DFE phase to paraelectric (PE) phase was highlighted. The CTFE termonomer content highly influences the crystalline structure and the electro-actives properties of terpolymer films (loss of ferroelectric behavior in favor of relaxor ferroelectric (RFE) behavior).We proved for the first time the existence of a continuous structural transition between RFE phase and PE phase around room temperature. This transition allows explaining exacerbated properties of these materials (dielectric constant and deformation under electric field).Finally, analogies of behavior between copolymers and terpolymers are discussed, especially the evolution of crystalline phases under electric field, in order to better understand how these electro-active materials work for their future development at industrial level.

The goal of this study is to present kinetic studies of (co)polymerization as well as the synthesis and characterization of amphiphilic copolymers with a fluorinated segment. Copolymers were obtained by RAFT (co)polymerizations using one-pot and miniemulsion methods. Different monomers were used to obtain stable selforganized systems, being that one of them was always fluorinated. The resulting copolymers showed different properties, especially when evaluating their selforganization. For this reason, different methodologies for self-organization were used, depending on the synthetic route by which the copolymers were obtained. The self-organization systems formed by the fluorinated amphiphilic copolymers were analyzed by dynamic light scattering (DLS) to determine the size and distribution of the species. The micellar systems analyzed showed great potential for the use in diagnostic imaging, which makes it possible to identify the presence of fluorine in the interior of the micelles through 19F NMR analysis. Relaxation times T1 were measured and values were similar to those reported in the literature. To reinforce the above statement, we performed cell viability assays, which demonstrated the biocompatibility of fluorinated amphiphilic copolymers. / O objetivo deste trabalho é apresentar estudos cinéticos de (co)polimerizações bem como a síntese e a caracterização de copolímeros anfifílicos contendo um segmento fluorado, os quais foram obtidos através de (co)polimerizações RAFT pelos métodos one-pot e miniemulsão. Diferentes monômeros foram utilizados para a obtenção de sistemas auto-organizados estáveis, sendo um deles sempre fluorado. Os copolímeros resultantes apresentaram propriedades distintas, principalmente quando se avalia a autoorganização dos mesmos. Por este motivo, diferentes metodologias para autoorganização foram utilizadas, dependendo da rota sintética pela qual os copolímeros foram obtidos. Os sistemas auto-organizados formados pelos copolímeros anfifílicos fluorados foram analisadas por espalhamento de luz dinâmico (DLS) para determinação de tamanho e distribuição das espécies. Os sistemas micelares analisados apresentaram grande potencial para utilização em diagnósticos por imagens sendo possível identificar a presença de flúor no interior das micelas através de análises por RMN 19F. Os tempos de relaxação T1 foram medidos e os valores encontrados foram semelhantes aos reportados na literatura. Para reforçar a afirmação acima, foram realizados ensaios de viabilidade celular que demonstraram a biocompatibilidade dos copolímeros anfifílicos fluorados.