Design, synthesis and thermal behaviour of a series of well-defined clickable and triggerable sulfonate polymers

In the printing industry, the exploitation of triggerable materials that can have their surface properties altered on application of a post-deposition external stimulus has been crucial for the production of robust layers and patterns. To this end, herein, a series of clickable poly(R-alkyl p-styrene sulfonate) homopolymers, with systematically varied thermally-labile protecting groups, has been synthesised via reversible addition-fragmentation chain transfer (RAFT) polymerisation. The polymer range has been designed to offer varied post-deposition thermal treatment to switch them from hydrophobic to hydrophilic. Suitable RAFT conditions have been identified to produce well-defined homopolymers (Đ, Mw/Mn 80% for all but one monomer) with controllable molar mass. Poly(p-styrene sulfonate) with an isobutyl protecting group has been shown to be the most readily thermolysed polymer that remains stable at room temperature, and was thus investigated further by incorporation into a diblock copolymer, P3HT-b-PiBSS, by click chemistry. The strategy for preparation of thermal modifiable block copolymers exploiting R-protected p-styrene sulfonates and azide-alkyne click chemistry presented herein allows the design of new, roll-to-roll processable materials for potential application in the printing industry, particularly organic electronics

Diketo-Pyrrolo Pyrrole-Based Acceptor-Acceptor Copolymers with Deep HOMO and LUMO Levels Absorbing in the Near Infrared

A series of acceptor-acceptor (A-A') alternated copolymers based on dithienodiketopyrrolo pyrrole were synthesized by copolymerizing it with itself and other different electron-poor monomers. The experimental and computed optoelectronic properties of four DPP-based copolymers, P(DPP-DPP) (with linear and branched chains), copolymer with diazapentalene P(DPP-DAP) and also with dioxothienopyrrolebenzodifurandione P(DPP-BTPBF), as well as thermal characterizations were described. UV-visible spectrophotometry and cyclic voltammetry were used to estimate the optical and electrochemical bandgaps, and were found as very small: 1.3, 1.0, and 0.9 eV for P(DPP-DPP), P(DPP-DAP), and P(DPP-BTPBF), respectively. The BTPBF unit allowed a strong reduction of the bandgap, leading to a broad absorption in the visible and near infra-red regions from 650 to 1450 nm. These results were compared to analogous donor-acceptor (D-A) copolymers previously reported, in which DPP is replaced by DTS, P(DTS-DPP), P(DTS-DAP), and P(DTS-BTPBF). The same trend was observed. By comparing A-A' to D-A' copolymers analogues, it was shown that the bandgap remained the same while both HOMO and LUMO levels were lowered by roughly 0.2 eV.Technologie alternative pour les photodétecteurs infrarougeE2

Janus organic semiconductor nanoparticles prepared by simple nanoprecipitation

Nanoparticles (NPs) of donor–acceptor organic semiconductors are produced by a one-step nanoprecipitation with Janus morphology. Electron donor P3HT was blended with electron acceptor PC61BM in tetrahydrofuran and then precipitated in water, first with surfactant and second without surfactant. Cryogenic transmission electron microscopy reveals an internal Janus structure at high magnification, for NPs which have, in the past, been reported to have a molecularly intermixed morphology. Synchrotron-based scanning transmission X-ray microscopy confirmed the segregation of the organic semiconductors and photoluminescence experiments showed an efficient electron transfer from P3HT to PC61BM. Organic field effect transistors were fabricated with these Janus NPs and showed that the positive charges can be efficiently transported through thin films. This behavior proves that the NPs possess an electron-accepting face (the PC61BM face) able to transport electrons and a hole-accepting face (the P3HT face) for the conduction of holes. Finally, the deposition of silver via the photoreduction of a silver salt (AgNO3(aq)) was demonstrated, as a proof of concept. These experiments show the potential of the Janus NPs for photovoltaics but also photocatalytic reactions in which reduction and oxidation reactions can occur at opposite sides of the nanoreactor (the individual Janus NPs).E2SEncres aqueuses colloïdales de semi-conducteurs organiques pour le photovoltaïqu

Copolymères à blocs rigide-rigide pour les cellules photovoltaïques organiques.

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 p-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 p-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.PAU-BU Sciences (644452103) / SudocSudocFranceF

Molten state reactivity of difunctional cyanates: Thermal and spectroscopic studies by liquid and solid CP-MAS13C-NMR

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Influence of the stoichiometry of epoxy-cyanate systems (non-catalyzed and catalyzed) on molten state reactivity

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A study of the mechanisms and kinetics of the molten state reaction of non-catalyzed cyanate and epoxy-cyanate systems

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End-capping of low band gap conjugated polymer for metal-oxide nanoparticles surface modification

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Hierarchically porous bio-inspired films prepared by combining “breath figure” templating and selectively degradable block copolymer directed self-assembly

International audiencePolymer films with hierarchical micro- and nano-porosities were prepared by combining the fast solvent evaporation “Breath Figure” (BF) method, exhibiting a highly regular honeycomb micro-porous texture, with the additional nanoscale self-assembly of polylactide-block-polystyrene (PLA-b-PS) diblock copolymers, PLA being used thereafter as a sacrificial component for nano-porosity