Low‐Permeability Poly(ether Ether Ketone)‐Based Ampholytic Membranes

Narducci, Riccardo; Pasquini, Luca; Chailan, Jean‐François; Knauth, Philippe; Vona, Maria Luisa Di

doi:10.1002/cplu.201600076

Cited by 9 publications

(4 citation statements)

References 64 publications

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“…The average mechanical properties are reported for the two polymers in Table . They are comparable to the properties of other aromatic polymer electrolytes ,,− and are typical of stiff ionomers below their glass-transition temperature. The glass-transition temperature of pristine PPO is known to be very high (212 °C) .…”

Section: Resultssupporting

confidence: 58%

Model Long Side-Chain PPO-Based Anion Exchange Ionomers: Properties and Alkaline Stability

et al. 2019

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The stability of anion exchange membranes is paramount for the use in alkaline fuel cells. Long chain ionomers are supposed to be more alkaline-resistant with respect to short chain isomers. In this paper the synthesis, properties and stability of ionomers with a long side chain are investigated. Poly(2,6-dimethyl-1,4-phenylene)oxide (PPO) is chosen as backbone, due to its reported stability in alkaline conditions. The functional group is pentyl-ammonium with trimethylamine (TMA) or 1,4-diazabicyclo[2.2.2]octane (DABCO) as model amines. The synthesis is carried out via metalation reaction and is optimized as a function of temperature and time. The water uptake is relatively low, in accordance with the large hydrophobicity of the PPO backbone. The through-plane ionic conductivity is consistent with literature data; it amounts to 15.3 mS/cm at 80 °C for the TMA derivative. The mechanical properties are typical of ionomers below the glass transition temperature (for the TMA derivative at ambient humidity: Young Modulus = 1310 ± 30 MPa). The stability in alkaline conditions, studied by thermogravimetric analysis and measurements of ionic conductivity and ion exchange capacity, is higher than that of short-side chain ionomers with the same basic group. The decrease of ionic conductivity (57 vs 22% residual conductivity after 72 h in 2 M NaOH at 80 °C) and IEC is monitored showing that the degradation is fast in the first hours and may by described by second order kinetics. These results help in selecting high performance anion exchange membranes for electrochemical energy technologies.

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Section: Resultssupporting

confidence: 58%

Model Long Side-Chain PPO-Based Anion Exchange Ionomers: Properties and Alkaline Stability

et al. 2019

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“…The co-deposition is anticipated to give an ampholytic membrane with a distribution of cation and anion exchange groups. [58][59][60] The electrodeposited samples were analysed by NMR spectroscopy (study of the chemical structure), optical and electron microscopy (study of the microstructure) and impedance spectroscopy (determination of the ionic conductivity).…”

Section: Introductionmentioning

confidence: 99%

“…The sequential deposition can be an elegant way for the synthesis of bipolar membranes with an ion‐blocking interface (change from cation to anion conduction). The co‐deposition is anticipated to give an ampholytic membrane with a distribution of cation and anion exchange groups [58–60] . The electrodeposited samples were analysed by NMR spectroscopy (study of the chemical structure), optical and electron microscopy (study of the microstructure) and impedance spectroscopy (determination of the ionic conductivity).…”

Section: Introductionmentioning

confidence: 99%

Ionomer Thin‐Films by Electrochemical Synthesis: Bipolar and Ampholytic Membranes

et al. 2021

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Thin-films of cation-conducting poly(styrene sulfonate) (PSS) and anion-conducting poly(N-vinyl-N-benzyl-N,N,N-trimethylammonium chloride) (PVBTMA) were electrochemically deposited. A low film thickness can be obtained, because the electrodeposition is a self-limiting process. Various cases were explored: i) the deposition of a single ionomer layer on various substrates, ii) the sequential deposition of the ionomers giving a bipolar membrane, and iii) the co-deposition of the ionomers giving an ampholytic membrane. The structure and micro-structure of the thin films were investigated by NMR spectroscopy and optical and scanning electron microscopy (SEM). Impedance spectroscopy in through-plane configuration revealed a large resistance of the bipolar membrane, due to the ionic blocking interface between the ionomers. The ampholytic membrane also showed a low conductivity, probably due to the loss of ionic carrier pairs that can leave the ionomer without break of electroneutrality.

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“…Polyelectrolytes are macromolecules with ionic groups grafted on the main or side chains. , They are called ionomers when a nanophase separation between the hydrophobic and hydrophilic domains is observed with the formation of nanosized ion conduction channels inside the solid polymer matrix . A well-defined nanophase separation promotes better-connected and less tortuous ion conduction channels and enhances the ionic conductivity, , but also the ionic permeability. − The selectivity of the ion transport process can therefore be improved by a careful balance between the hydrophilic and hydrophobic domains.…”

Section: Introductionmentioning

confidence: 99%

Hydration and Ionic Conductivity of Model Cation and Anion-Conducting Ionomers in Buffer Solutions (Phosphate, Acetate, Citrate)

et al. 2018

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We studied the gravimetric and volumetric water uptake and ionic conductivity of two model ionomers, cation-conducting sulfonated poly(ether ether ketone) (SPEEK) and anion-conducting polysulfone-trimethylammonium chloride (PSU-TMA), after immersion in phosphate, acetate and citrate buffer solutions. The equilibrium swelling of SPEEK and PSU-TMA ionomer networks was determined as a function of pH and buffer composition. The hydration data can be interpreted using the osmotic swelling pressure dependence on the ion exchange capacity of the ionomers and the concentration of the electrolyte solutions. In the case of SPEEK, anisotropic swelling is observed in diluted buffer solutions, where the swelling pressure is higher. A large water uptake is observed for citrate ions, due to the large hydration of this bulky anion. The ionic conductivity is related to the conducting ions and, in the case of SPEEK, to sorbed excess electrolyte. The highest ionic conductivity is observed after immersion in phosphate buffers.Ionic cross-linking is for the first time observed in the case of an anion-conducting ionomer in presence of divalent citrate ions, which limits the volumetric swelling and decreases the ionic conductivity of PSU-TMA.

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Low‐Permeability Poly(ether Ether Ketone)‐Based Ampholytic Membranes

Cited by 9 publications

References 64 publications

Model Long Side-Chain PPO-Based Anion Exchange Ionomers: Properties and Alkaline Stability

Model Long Side-Chain PPO-Based Anion Exchange Ionomers: Properties and Alkaline Stability

Ionomer Thin‐Films by Electrochemical Synthesis: Bipolar and Ampholytic Membranes

Hydration and Ionic Conductivity of Model Cation and Anion-Conducting Ionomers in Buffer Solutions (Phosphate, Acetate, Citrate)

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