The incorporation of substituted stilbenes in copolymers affects the resulting solution properties and their controlled radical polymerizations. Substituted stilbene monomers readily polymerize in an alternating fashion with acceptor comonomers such as maleic anhydride and maleimide. These sterically crowded polymer backbones are classified as semi-rigid. As this is an uncommon category of polymer backbone rigidity, examples of semi-rigid and rigid polyzwitterions in the literature were reviewed as well as stilbene-containing semi-rigid polymers. Using a deprotection strategy, anionic polyelectrolytes and polyampholytes of stilbene-maleic anhydride copolymers were synthesized and characterized by first synthesizing organic-soluble polymer precursors. Solution shear rheology and statistical segment length measurements reveal that carboxylated polyanions containing stilbene and maleic acid remain semi-rigid in aqueous solutions. It was found that these semi-rigid polyanions exhibited excellent anti-HIV activity possibly due to their more extended polymer chains. This was the first time that intrinsic polymer rigidity was introduced as a possible design parameter for microbicidal applications. Reversible addition fragmentation chain transfer (RAFT) polymerization techniques were used to copolymerize 4-diethylaminostilbene with maleic anhydride. These new semi-rigid copolymers were incorporated into double hydrophilic block copolymers (DHBCS) containing semi-rigid and flexible segments. The subsequent solutions properties of these DHBCs were evaluated with respect to pH and salt responsiveness. Notably, the DHBCs exhibited a "like-charge" attraction as ionic strength increased which was attributed to the semi-rigid character of the polyampholyte block copolymer. / Ph. D.

The research in this dissertation is focused on the synthesis and characterization of sterically crowded, precisely charged polyelectrolytes based on substituted stilbene comonomers. New sterically crowded polyelectrolytes based on functionalized stilbenes with maleic anhydride or functionalized N-phenylmaleimides were prepared via a "protected" precursor polymer strategy. The polyelectrolyte precursors readily dissolved in organic solvents and were characterized by 1H NMR, SEC, TGA, and DSC. The polyelectrolytes were obtained via simple deprotection chemistries. The use of different combinations of the donor-acceptor comonomer pairs and the alternating copolymerization of these comonomers lead to precise control over charge density and placement of charged groups along the polymer backbone. Analogous styrenic copolymers, for direct comparison to the stilbene structures, were also prepared. Broad peaks in 1H NMR spectra were observed. There were no thermal transitions measured by DSC below the degradation temperature. A strong polyelectrolyte effect, for both stilbene and styrene copolymers, occurred in deionized water and was suppressed by adding NaCl to the polymer solution. These results are not consistent with "rigid" rod polyelectrolytes in which chain collapse in the presence of added salt and chain expansion on dilution should not be observed. In response to these observations persistence length measurements were conducted on the stilbene and styrene copolymers to assess directly the steric crowding effect of added phenyl groups in stilbene copolymers. Both SEC and SAXS measurements were used to obtain persistence lengths. The results from three different approaches, Bohdanecký, graphical and Sharp and Bloomfield Global, were in good agreement. The persistence lengths of stilbene containing copolymers range from 3 to 6 nm and the added phenyl groups increase the rigidity of the polymer chain by about 30-50%. This puts these polymers into a broadly defined "semi-rigid" category of polymers and is consistent with the solution polyelectrolyte effect observed. In dilute solution characterization of stilbene containing polyanions, a 2-step dissociation behavior was observed for the two adjacent carboxylic acids in maleic acid containing polyanions. Stilbene polyanion solutions showed high Rh values in deionized water as shown by DLS measurements and a decrease of Rh values followed by aggregation upon gradual addition of salt. Bimodal peaks were observed in SEC measurements with the copolymer of 4-methylstilbene and maleic anhydride. DLS measurements indicated interchain aggregation as the origin of the apparent high molecular weight fraction. The antiviral activity of the polyanion based on sodium 4-styrenesulfonate and N-(4-sodium sulfophenyl)maleimide was found to be ~50 times higher than the microbicide, sodium poly(styrene sulfonate). The early study of antiviral activities of carboxylated stilbene and styrene polyanions also showed promising results. The synthesis of methyl sulfonate ester-functionalized polyanion precursors was attempted because they can be characterized without the complications caused by directly using charged sulfonate groups. / Ph. D.

Alternating copolymers represent a special class of copolymers in which the two comonomers copolymerize in a regular alternating sequence along the polymer chain. Of particular interest in our group are the stilbene-maleic anhydride/maleimide alternating copolymers. These copolymers possess sterically congested backbones and precisely placed functional groups arising from the strictly alternating copolymerization. The research in this dissertation is focused on the synthesis, characterization, and potential application of functionalized copolymers that contain semi-rigid alternating copolymer sequences. The fluorescence properties of a series of non-conjugated, tert-butyl carboxylate functionalized alternating copolymers were investigated. Extraordinarily high fluorescent intensity with excellent linearity was observed for the di-tert-butyl group-containing stilbene and maleic anhydride alternating copolymer in THF. We attributed the origin of the strong fluorescence to the “through space” π – π interactions between the phenyl rings from the stilbene and C=O groups from the anhydride. The fluorescence was maintained when the copolymer was deprotected and hydrolyzed and the resulting carboxylic acid-functionalized copolymer was dissolved in water at neutral pH. The tert-butyl carboxylate functionalized alternating copolymer sequences were incorporated into highly crosslinked polymer networks using suspension polymerization. After removing the tert-butyl groups by acidic hydrolysis, the surface area of the networks increased significantly. Using this facile two-step strategy, we were able to achieve nanoporous polymers with BET surface area up to 817 m2/g and carboxylic acid-functionalized surfaces. The BET surface area of deprotected polymers increased with increasing crosslinking density, and the stilbene-containing polymers showed systematically higher BET surface area than the styrene-containing polymers due to the stiffness of the alternating sequences. The resulting nanoporous polymers have potential to be employed as solid sorbents for CO2. The same tert-butyl carboxylate functionalized alternating copolymer sequences were also incorporated into microgels via miniemulsion polymerization. The miniemulsion technique ensured the successful synthesis of microgels with ~100 nm diameter using solid stilbene and maleimide monomers. The resulting tert-butyl carboxylate-containing microgels were converted into carboxylic acid-containing aqueous microgels by acid hydrolysis. These aqueous microgels showed good and reversible lead and copper ion adsorption capacities. Amine-functionalized nanoporous polymers were synthesized by the post-modification of highly-crosslinked divinylbenzene-maleic anhydride polymers. High amine-contents were achieved by covalently attaching multiamines to the acid-chloride functionalized polymer surface. The resulting polymers showed medium to high BET surface areas (up to 500 m2/g) and high CO2 capture capacities. / PHD

L'efficacité des cellules photovoltaïques organiques est influencée par la morphologie du mélange composant la couche active. L'objectif de cette thèse a été d'élaborer un agent compatibilisant pour stabiliser la morphologie du mélange P3HT:PCBM. Nous avons choisi de synthétiser des copolymères alternant motifs C60 et polythiophène pour améliorer la miscibilité entre P3HT et PCBM. Les copolymères ont été réalisés par polycondensation d'un dérivé C60 avec plusieurs oligothiophènes régioréguliers de difonctionnalité contrôlée. Une attention particulière a été accordée aux conditions de polycondensation qui ont été optimisées pour favoriser de hauts degrés de polymérisation. Les caractérisations structurales, optiques et électrochimiques des matériaux ont été réalisées. Leur effet compatibilisant a été évalué en caractérisant la morphologie de la couche active par des mesures en cellules photovoltaïques, des observations par microscopie à force atomique et des calculs d'énergies de surface. / Efficiency of organic photovoltaic solar cells is influenced by the active layer's morphology. The aim of this thesis was to elaborate a compatibilising agent which could stabilise the morphology of the P3HT:PCBM blend. We chose to synthesize alternating copolymers based on fullerene and polythiophene blocks to improve compatibility between P3HT and PCBM. The synthesis of copolymers has been achieved by polycondensation of a fullerene derivative with several regioregular oligothiophenes for which difunctionality was well controlled. Particular care has been given to the optimisation of polycondensation conditions in order to favour high polymerisation degrees. Structural, optical and electrochemical characterisations have been realized. The compatibilising effect of our copolymers on the active layer morphology has been investigated on the basis of photovoltaic measurements, atomic force microscopy observations and surface energy calculations.

Les performances des cellules photovoltaïques organiques de type hétérojonction en volume sont entre autres influencées par les propriétés opto-électroniques du polymère semiconducteur donneur d’électrons. L’objectif de cette thèse était de développer de nouveaux polymères π-conjugués pour permettre une meilleure exploitation du spectre solaire et donc améliorer la photogénération des charges. Pour cela, plusieurs dérivés de polythiophènes comportant des substituants aromatiques phényles ont été synthétisés par la méthode de GRIM, à noter l’homopolymère poly[(3-(4-hexylphényl) thiophène] (P3HPT) et le copolymère à blocs poly[3-(4-hexylphényl)thiophène]-bloc-poly(3-hexylthiophène) (P3HPT-b-P3HT). Nous avons également étudié une nouvelle famille de polymères à faible bande interdite basés sur l’alternance d’unités thiophène et dithiéno[3,2-b:2′,3′-d]silole riches en électrons et 2,1,3- benzothiadiazole pauvres en électrons. Après synthèse des différents monomères, les copolymères alternés ont été ensuite obtenus par polycondensation par couplage de Stille. Les différents matériaux synthétisés ont été d’abord caractérisés par analyse thermogravimétrique et par calorimétrie différentielle à balayage afin d’étudier leurs propriétés thermiques. Ensuite, des caractérisations structurales (en particulier DRX et neutrons), optiques (UV-visible) et morphologiques (AFM) ont été réalisées. A partir des résultats obtenus, nous avons pu évaluer les relations entre les structures et les propriétés des matériaux. Finalement, des cellules photovoltaïques à base des polymères synthétisés ont été réalisées et leurs performances ont été corrélées aux propriétés des matériaux. / The performances of organic solar cells based on the concept of bulk heterojunction configuration are strongly influenced by the optoelectronic properties of the electron donor polymer. The aim of this thesis was to develop new π-conjugated polymers to allow a better exploitation of the solar spectrum and thus improving the photogeneration of charges. For this,several polythiophene derivatives substituted by phenyl aromatic groups have been synthesized by the GRIM method, note the homopolymer poly[(3-(4-hexylphenyl)thiophene] (P3HPT) and the diblock copolymer poly[3-(4- exylphenyl)thiophene]-block-poly(3- hexylthiophène) (P3HPT-b-P3HT). We also studied a new family of low band gap polymers based on the alternation of electron-rich thiophene and dithieno[3,2-b:2′,3′-d]silole units andelectron-deficient 2,1,3-benzothiadiazole units. After synthesis of the various monomers, alternating copolymers were then obtained by Stille cross-coupling polycondensation. The different synthesized materials were first characterized by thermogravimetric analysis and by differential scanning calorimetry to study their thermal properties. Then, structural(especially XRD and neutron), optical (UV-visible) and morphological (AFM) characterizations were performed. From the obtained results, we were able to evaluate the relation between structures and properties of materials. Finally, photovoltaic cells based on the synthesized polymers were performed and their performances were correlated to material properties.