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Olesia Danyliv - One of the best experts on this subject based on the ideXlab platform.
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aromatic ionic monomer bearing perfluorosulfonate moiety and its polycondensation toward high performance superacid ionomers
Journal of Fluorine Chemistry, 2016Co-Authors: Olesia Danyliv, Cristina Iojoiu, Valessa Barbier, Vincent Martin, Jeanyves SanchezAbstract:Abstract Bottom-up synthesis of perfluorosulfonic acid ionomers based on the high performance backbone is rarely performed, due to the difficulty of obtaining ionic Monomers of high purity. Such an approach, however, results in ionic polymers of well-defined chemical structure and ionic group distribution. Here copper-mediated synthesis of an ionic monomer bearing a perfluorosulfonate group and two polymerizable fluorine-sites was studied. Its synthesis and purification were investigated with accuracy to find the least time-consuming and the most technologically advantageous protocol (the overall yield of the monomer consisted 76%). The monomer was subjected to polycondensation with commercial non-ionic Monomers, and a series of ionomers of different ionic concentration (and thus ion exchange capacity, IEC) was obtained. The resultant ionomers demonstrated excellent film-forming properties. The obtained membranes were characterized by high glass transition temperature (>160 °C) and high proton conductivity (10 −2 –10 −1 S/cm at 60–90 °C and 95% relative humidity). Such results make these materials promising for use in fuel cells.
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highly phase separated aromatic ionomers bearing perfluorosulfonic acids by bottom up synthesis effect of cation on membrane morphology and functional properties
Macromolecules, 2016Co-Authors: Olesia Danyliv, Cristina Iojoiu, Jeanyves Sanchez, Sandrine Lyonnard, Nicolas Sergent, Emilie PlanesAbstract:Proton-conducting aromatic-based ionomers bearing superacid side chains are usually synthesized by polymer postmodification, which does not allow controlling ion exchange capacity and ionic group distribution along the ionomer and, thus, its chemical structure and functional properties. Bottom-up approach overcomes this problem. Here, we report the preparation of a novel ionic monomer and its polycondensation with commercial Monomers. The obtained random ionomers are the first to show high phase separated organization at macro-, micro-, and nanoscale, common to the reference proton-conducting material Nafion. Additionally, membranes were cast from the solutions of ionomers in their Li+ and K+ forms in order to study the cation’s influence on both morphology and performance of the materials. The difference in ionic domain organization, depending on the initial cationic form of the ionomers, was reported for the first time. The proposed materials show superior proton conductivity than Nafion, especially at ...
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new membranes based on high performance polymers for proton exchange membrane fuel cells pemfc
2015Co-Authors: Olesia DanylivAbstract:The current work is directed to production of a proton conducting membrane for a proton electrolyte membrane fuel cell (PEMFC) as a main goal. The originality and the challenge of the membrane elaboration lie in the multi-step procedure: starting with the synthesis of a simple unit – an ionic monomer, continuing with polymerization and overall estimation of the polymer performance at laboratory scale, and ending with production of the required material of industrial quantity and testing in real conditions. All the steps, except the last one, are explicitly studied. Firstly, much attention in the dissertation is paid to description of a protocol for production and purification of the ionic Monomers. It is due to complexity of ionic interactions in a system ‘product-solvent' and due to the main requirement of high purity for a monomer that attentive synthesis and treatment of the Monomers must be provided. In total three new Monomers, bearing perfluorosulfonic acid chains, are reported. Then, a number of polymerization reactions with different commercial non-ionic Monomers are proposed. Two main families of proton conducting ionomers are described: random poly(arylene ether)s (PAEs) and poly(arylene ether sulfone)s (PAESs), both random and block-copolymers. They are synthesized in series of different IEC in order to follow the impact of the ionic group to the properties of the material. Additionally, a new structure of the ionomer is proposed, where the block-copolymer contains a hydrophilic block, synthesized from two Monomers, bearing perfluorosulfonic acid (PFSA) groups. It allows maximally approximating the superacid lateral groups along the polymer chain that, most probably, contributes to better organization and interaction between the ionic sites. For further characterization of the novel polymers, they are cast to membranes by casting-evaporation method from their solutions in dimethylacetamide (DMAc). The influence of production temperature is described briefly. The membranes of different series are compared between each other and to Nafion as a reference material. It is known that Nafion acquires its high performance due to: i) presence of superacid PFSA lateral groups, and ii) organization of polymer chains into well-separated proton-conductive (hydrophilic) and mechanically stable (hydrophobic) domains. However, production of this material comprises dangerous and expensive procedures of manipulation with fluorinated gases, since this ionomer contains a Teflon-type backbone. Moreover, transition temperature of the perfluorinated main chain is lower, than the required temperature of the ionomer functioning in a PEMFC. The novel ionomers are further characterized in terms of thermo-mechanical properties, stability, conductivity, bulk morphology. They exhibit: i) high transition temperatures, which allows utilization of these polymers at conditions of a PEMFC functioning; ii) phase separation phenomenon, which suggests the materials to have morphology with distinct domains for proton conduction, iii) highly organized structuring, which is rare to clearly evidence on aromatic materials; iv) high proton conductivity for several polymer series, which over-perform Nafion even at reduced humidity. Based on these results, some of the synthesized materials are considered to be promising in a PEMFC, but further study in real conditions must be provided. Additionally, the current work is pioneering in the way of production of the ionomers, therefore, more different series of polymers are previewed to be synthesized out of the ionic Monomers, proposed here. Variety of the ionic Monomers may be enlarged as well by changing the PFSA groups to perfluorosulfonimide ones or by searching for other fluorinated commercial materials that might be modified into Monomers with two functional groups for polycondensation. Thus, the main objectives, set for the current work, are fulfilled.
Jeanyves Sanchez - One of the best experts on this subject based on the ideXlab platform.
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aromatic ionic monomer bearing perfluorosulfonate moiety and its polycondensation toward high performance superacid ionomers
Journal of Fluorine Chemistry, 2016Co-Authors: Olesia Danyliv, Cristina Iojoiu, Valessa Barbier, Vincent Martin, Jeanyves SanchezAbstract:Abstract Bottom-up synthesis of perfluorosulfonic acid ionomers based on the high performance backbone is rarely performed, due to the difficulty of obtaining ionic Monomers of high purity. Such an approach, however, results in ionic polymers of well-defined chemical structure and ionic group distribution. Here copper-mediated synthesis of an ionic monomer bearing a perfluorosulfonate group and two polymerizable fluorine-sites was studied. Its synthesis and purification were investigated with accuracy to find the least time-consuming and the most technologically advantageous protocol (the overall yield of the monomer consisted 76%). The monomer was subjected to polycondensation with commercial non-ionic Monomers, and a series of ionomers of different ionic concentration (and thus ion exchange capacity, IEC) was obtained. The resultant ionomers demonstrated excellent film-forming properties. The obtained membranes were characterized by high glass transition temperature (>160 °C) and high proton conductivity (10 −2 –10 −1 S/cm at 60–90 °C and 95% relative humidity). Such results make these materials promising for use in fuel cells.
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highly phase separated aromatic ionomers bearing perfluorosulfonic acids by bottom up synthesis effect of cation on membrane morphology and functional properties
Macromolecules, 2016Co-Authors: Olesia Danyliv, Cristina Iojoiu, Jeanyves Sanchez, Sandrine Lyonnard, Nicolas Sergent, Emilie PlanesAbstract:Proton-conducting aromatic-based ionomers bearing superacid side chains are usually synthesized by polymer postmodification, which does not allow controlling ion exchange capacity and ionic group distribution along the ionomer and, thus, its chemical structure and functional properties. Bottom-up approach overcomes this problem. Here, we report the preparation of a novel ionic monomer and its polycondensation with commercial Monomers. The obtained random ionomers are the first to show high phase separated organization at macro-, micro-, and nanoscale, common to the reference proton-conducting material Nafion. Additionally, membranes were cast from the solutions of ionomers in their Li+ and K+ forms in order to study the cation’s influence on both morphology and performance of the materials. The difference in ionic domain organization, depending on the initial cationic form of the ionomers, was reported for the first time. The proposed materials show superior proton conductivity than Nafion, especially at ...
Cristina Iojoiu - One of the best experts on this subject based on the ideXlab platform.
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aromatic ionic monomer bearing perfluorosulfonate moiety and its polycondensation toward high performance superacid ionomers
Journal of Fluorine Chemistry, 2016Co-Authors: Olesia Danyliv, Cristina Iojoiu, Valessa Barbier, Vincent Martin, Jeanyves SanchezAbstract:Abstract Bottom-up synthesis of perfluorosulfonic acid ionomers based on the high performance backbone is rarely performed, due to the difficulty of obtaining ionic Monomers of high purity. Such an approach, however, results in ionic polymers of well-defined chemical structure and ionic group distribution. Here copper-mediated synthesis of an ionic monomer bearing a perfluorosulfonate group and two polymerizable fluorine-sites was studied. Its synthesis and purification were investigated with accuracy to find the least time-consuming and the most technologically advantageous protocol (the overall yield of the monomer consisted 76%). The monomer was subjected to polycondensation with commercial non-ionic Monomers, and a series of ionomers of different ionic concentration (and thus ion exchange capacity, IEC) was obtained. The resultant ionomers demonstrated excellent film-forming properties. The obtained membranes were characterized by high glass transition temperature (>160 °C) and high proton conductivity (10 −2 –10 −1 S/cm at 60–90 °C and 95% relative humidity). Such results make these materials promising for use in fuel cells.
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highly phase separated aromatic ionomers bearing perfluorosulfonic acids by bottom up synthesis effect of cation on membrane morphology and functional properties
Macromolecules, 2016Co-Authors: Olesia Danyliv, Cristina Iojoiu, Jeanyves Sanchez, Sandrine Lyonnard, Nicolas Sergent, Emilie PlanesAbstract:Proton-conducting aromatic-based ionomers bearing superacid side chains are usually synthesized by polymer postmodification, which does not allow controlling ion exchange capacity and ionic group distribution along the ionomer and, thus, its chemical structure and functional properties. Bottom-up approach overcomes this problem. Here, we report the preparation of a novel ionic monomer and its polycondensation with commercial Monomers. The obtained random ionomers are the first to show high phase separated organization at macro-, micro-, and nanoscale, common to the reference proton-conducting material Nafion. Additionally, membranes were cast from the solutions of ionomers in their Li+ and K+ forms in order to study the cation’s influence on both morphology and performance of the materials. The difference in ionic domain organization, depending on the initial cationic form of the ionomers, was reported for the first time. The proposed materials show superior proton conductivity than Nafion, especially at ...
Valessa Barbier - One of the best experts on this subject based on the ideXlab platform.
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aromatic ionic monomer bearing perfluorosulfonate moiety and its polycondensation toward high performance superacid ionomers
Journal of Fluorine Chemistry, 2016Co-Authors: Olesia Danyliv, Cristina Iojoiu, Valessa Barbier, Vincent Martin, Jeanyves SanchezAbstract:Abstract Bottom-up synthesis of perfluorosulfonic acid ionomers based on the high performance backbone is rarely performed, due to the difficulty of obtaining ionic Monomers of high purity. Such an approach, however, results in ionic polymers of well-defined chemical structure and ionic group distribution. Here copper-mediated synthesis of an ionic monomer bearing a perfluorosulfonate group and two polymerizable fluorine-sites was studied. Its synthesis and purification were investigated with accuracy to find the least time-consuming and the most technologically advantageous protocol (the overall yield of the monomer consisted 76%). The monomer was subjected to polycondensation with commercial non-ionic Monomers, and a series of ionomers of different ionic concentration (and thus ion exchange capacity, IEC) was obtained. The resultant ionomers demonstrated excellent film-forming properties. The obtained membranes were characterized by high glass transition temperature (>160 °C) and high proton conductivity (10 −2 –10 −1 S/cm at 60–90 °C and 95% relative humidity). Such results make these materials promising for use in fuel cells.
Ralph H Colby - One of the best experts on this subject based on the ideXlab platform.
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linear viscoelastic and dielectric properties of phosphonium siloxane ionomers
ACS Macro Letters, 2013Co-Authors: Quan Chen, Siwei Liang, Huai Suen Shiau, Ralph H ColbyAbstract:The linear viscoelastic (LVE) and dielectric relaxation spectroscopic (DRS) properties of polysiloxanes with phosphonium (fraction f) and oligo(ethylene oxide) (fraction 1 – f) side groups with a fraction of ionic Monomers f = 0–0.26 have been studied. LVE master curves of those ionomers have been constructed. The ionic dissociation has been witnessed as a delayed polymer relaxation in LVE with increasing ion content, as well as an α2 ionic segmental relaxation process in DRS. LVE exhibits glassy and delayed rubbery relaxation at low ionic fraction f ≤ 11%, where the ionic dissociation time detected in DRS enables description of LVE with a sticky Rouse model. In contrast, the glassy and rubbery stress relaxation moduli merge into one broad process at high f ≥ 22%, where the whole LVE response from glassy to terminal relaxation can be described phenomenologically by a single Kohlrausch–Williams–Watts (KWW) equation with the lowest stretching exponent β = 0.10 ever seen for polymeric liquids, describing LVE...
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polymerized ionic liquids with enhanced static dielectric constants
Macromolecules, 2013Co-Authors: Hyeok U Choi, James Runt, Anuj Mittal, Terry L Price, Harry W Gibson, Ralph H ColbyAbstract:Dielectric spectroscopy was used to determine the static dielectric constants (es) of imidazolium acrylates and methacrylates and their ionomers, with different imidazolium pendant structures containing a combination of alkylene [(CH2)n, n = 5 or 10] and ethyleneoxy [(CH2CH2O)n, n = 4 or 7.3 (the average of a mixture of n = 1 to 20)] units as spacers between the backbone and the imidazolium cation. All Monomers and polymers exhibited two dipolar relaxations, assigned to the usual segmental motion (α) associated with the glass transition and a lower frequency relaxation (α2), attributed to ions rearranging. From the analysis of the static dielectric constants using the Kirkwood g correlation factor, the dipoles in conventional (smaller) ionic liquids prefer antiparallel alignment (g ≈ 0.1), lowering es values (≤30), because their polarizability volumes Vp strongly overlap, whereas the dipoles in the larger ionic liquid Monomers display g of order unity and 50 ≤ es ≤ 110. A longer spacer leads to higher sta...
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synthesis and lithium ion conduction of polysiloxane single ion conductors containing novel weak binding borates
Chemistry of Materials, 2012Co-Authors: Siwei Liang, Hyeok U Choi, Wenjuan Liu, James Runt, Ralph H ColbyAbstract:Three borate Monomers: lithium triphenylstyryl borate (B1), a variant with three ethylene oxides between the vinyl and the borate (B2) and a third with perfluorinated phenyl rings (B3) were synthesized and used to prepare polysiloxane ionomers based on cyclic carbonates via hydrosilylation. B1 ion content variations show maximum 25 °C conductivity at 8 mol %, reflecting a trade-off between carrier density and glass transition temperature (Tg) increase. Ethylene oxide spacers (B2) lower Tg, and increase the dielectric constant, both raising conductivity. Perfluorinating the four phenyl rings (B3) lowers the ion association energy, as anticipated by ab initio estimations. This increases conductivity, a direct result of 3 times higher measured carrier density. The ∼9 kJ/mol activation energy of simultaneously conducting ions is less than half that of ionomers with either sulfonate or bis(trifluoromethanesulfonyl) imide anions, suggesting that ionomers with weak-binding borate anions may provide a pathway to ...
