Fully Aromatic Block Copolymers for Fuel Cell Membranes with Densely Sulfonated Nanophase Domains

Takamuku, Shogo; Jannasch, Patric

doi:10.1002/marc.201000683

Cited by 27 publications

(22 citation statements)

References 22 publications

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“…g −1 . [26] In the present work, we have further developed the approach and have synthesized and investigated a full range of multiblock copolymers with different compositions, block lengths,…”

Section: Hydroxy-terminated Paes Oligomersmentioning

confidence: 99%

Multiblock Copolymers with Highly Sulfonated Blocks Containing Di‐ and Tetrasulfonated Arylene Sulfone Segments for Proton Exchange Membrane Fuel Cell Applications

Takamuku¹,

Jannasch²

2011

Advanced Energy Materials

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(arylene ether sulfone)s with different block lengths and ionic contents are tailored for durable and proton-conducting electrolyte membranes. Two series of fully aromatic copolymers are prepared by coupling reactions between non-sulfonated hydrophobic precursor blocks and highly sulfonated hydrophilic precursor blocks containing either fully disulfonated diarylsulfone or fully tetrasulfonated tetraaryldisulfone segments. The sulfonic acid groups are exclusively introduced in ortho positions to the sulfone bridges to impede desulfonation reactions and give the blocks ion exchange capacities (IECs) of 4.1 and 4.6 meq. g −1 , respectively. Solvent cast block copolymer membranes show well-connected hydrophilic nanophase domains for proton transport and high decomposition temperatures above 310 °C under air. Despite higher IEC values, membranes containing tetrasulfonated tetraaryldisulfone segments display a markedly lower water uptake than the corresponding ones with disulfonated diarylsulfone segments when immersed in water at 100 °C, presumably because of the much higher chain stiffness and glass transition temperature of the former segments. The former membranes have proton conductivities in level of a perfluorosulfonic acid membrane (NRE212) under fully humidified conditions. A membrane with an IEC of 1.83 meq. g −1 reaches above 6 mS cm −1 under 30% relative humidity at 80 °C, to be compared with 10 mS cm −1 for NRE212 under the same conditions.solubilization of conductive polymers such as poly(thiophene)s. [4] Still, perhaps the most important application area of these robust polymers is currently as proton exchange membranes for polymer electrolyte fuel cells, which are highly energy efficient and potentially environmentally benign power devices. [5,6] Today, perfluorosulfonic acid polymers such as Nafion are considered as state-of-the-art membranes because of their high chemical stability and high proton conductivity under a wide humidity range at moderate operating temperatures. [7,8] Nevertheless, the Nafion membrane suffers from general disadvantages such as high cost, high fuel permeability and a low mechanical modulus. More seriously, the Nafion membrane has a tendency to dehydrate above 80 °C, leading to lower conductivities. It thus fails to meet the current industrial demands which call for operating temperatures above 100 °C. [9,10] Over the last decade, an extensive research effort has been directed toward developing alternative membranes based on sulfonated hydrocarbon polymers to overcome the drawbacks of Nafion. [11,12] The use of hydrocarbon-based monomers and building blocks has widely expanded the possibilities to vary and control the structure and function of the membranes in relation to fluorocarbon-based approaches. For example, a wide range of sulfonated high-performance aromatic polymers has been prepared and their films have subsequently been evaluated and demonstrated as prospective fuel cell membranes. Among these polymers, sulfonated poly(arylene ether sulfone)s (SPAESs) have been ex...

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Section: Hydroxy-terminated Paes Oligomersmentioning

confidence: 99%

Multiblock Copolymers with Highly Sulfonated Blocks Containing Di‐ and Tetrasulfonated Arylene Sulfone Segments for Proton Exchange Membrane Fuel Cell Applications

Takamuku¹,

Jannasch²

2011

Advanced Energy Materials

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“…[33][34][35] In this work, SPAES copolymers with tetrasulfonated units were prepared by using the sBCPSBPos monomer in direct polycondensations. [33][34][35] In this work, SPAES copolymers with tetrasulfonated units were prepared by using the sBCPSBPos monomer in direct polycondensations.…”

Section: Preparation Of Sulfonated Statistical Copolymersmentioning

confidence: 99%

“…We have previously prepared SPAESs with tetrasulfonated segments prepared by postpolymerization sulfonation by using organolithium chemistry. [33][34][35] In this work, SPAES copolymers with tetrasulfonated units were prepared by using the sBCPSBPos monomer in direct polycondensations. This allows more straightforward and versatile synthetic approaches, which results in a greater control and variability of the distribution of the acid groups along the polymer backbone.…”

Section: Preparation Of Sulfonated Statistical Copolymersmentioning

confidence: 99%

Segmented Tetrasulfonated Copoly(Arylene Ether Sulfone)s: Improving Proton Transport Properties by Extending the Ionic Sequence

2013

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The morphologies and proton-transport efficiencies of segmented copoly(arylene ether sulfone) ionomers that contain tetrasulfonated sequences are compared with the corresponding copolymers with disulfonated sequences. Tetrasulfonated 4,4'-bis[(4-chlorophenyl)sulfonyl]-1,1'-biphenyl (sBCPSBP) is synthesized by metalation and sulfination. This new monomer is then used in K(2)CO(3)-mediated polycondensations of mixtures with 4,4'-dichlorodiphenyl sulfone (DCDPS) and 4,4'-dihydroxybiphenyl in dimethyl sulfoxide at 110 °C to prepare segmented copolymers with tetrasulfonated units. The corresponding disulfonated copolymers are prepared by using disulfonated DCDPS instead of sBCPSBP. Small-angle X-ray scattering measurements of the fully aromatic copolymer membranes show ionomer peaks that indicate significantly larger characteristic separation lengths of the tetrasulfonated copolymers compared to those of the corresponding disulfonated copolymers with similar ionic contents. This implies a much more efficient phase separation of the ionic groups in the segmented tetrasulfonated copolymer membranes, especially at low-to-medium ionic contents. The enhanced phase separation has a pronounced positive effect on water uptake characteristics and proton transport properties. Under a reduced relative humidity (RH), the tetrasulfonated copolymer membranes show a significantly higher conductivity than the disulfonated ones, particularly at low-to-medium ionic contents. At an ion-exchange capacity of 1 meq g(-1), the conductivity of the tetrasulfonated copolymer membrane at 30 % RH is higher than that of the disulfonated membrane at 90 % RH. Because of their relative ease of synthesis, segmented copolymers based on well-designed multisulfonated monomers may provide a viable alternative to the more complex sulfonated block and graft copolymers for use as fuel-cell membranes.

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“…Block copolymer architecture in the form of comb-shaped [28] and triblock architecture [29] has also been shown to be a highly effective in inducing proton channel formation for good conduction at low RH. Another approach to enhance phase separated structures and PEM performance can be realized by introducing densely sulfonated structures into the aromatic polymer backbone [30][31][32][33][34][35]. The large difference in polarity between the densely sulfonated units and hydrophobic units of the polymers promotes the formation of well-defined nanophase-separated structures, which can induce efficient proton conduction.…”

Section: Introductionmentioning

confidence: 98%

Proton-conducting membranes from poly(ether sulfone)s grafted with sulfoalkylamine

Wang

Lee

Shin

et al. 2013

Journal of Membrane Science

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Fully Aromatic Block Copolymers for Fuel Cell Membranes with Densely Sulfonated Nanophase Domains

Cited by 27 publications

References 22 publications

Multiblock Copolymers with Highly Sulfonated Blocks Containing Di‐ and Tetrasulfonated Arylene Sulfone Segments for Proton Exchange Membrane Fuel Cell Applications

Multiblock Copolymers with Highly Sulfonated Blocks Containing Di‐ and Tetrasulfonated Arylene Sulfone Segments for Proton Exchange Membrane Fuel Cell Applications

Segmented Tetrasulfonated Copoly(Arylene Ether Sulfone)s: Improving Proton Transport Properties by Extending the Ionic Sequence

Proton-conducting membranes from poly(ether sulfone)s grafted with sulfoalkylamine

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