Effect of the Hydrophilic Component in Aromatic Ionomers: Simple Structure Provides Improved Properties as Fuel Cell Membranes
Effect of the Hydrophilic Component in Aromatic Ionomers: Simple Structure Provides Improved Properties as Fuel Cell Membranes
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DOI：
10.1021/acsmacrolett.5b00385
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发表时间：
2015-07-01
影响因子：
7.015
通讯作者：
Miyatake, Kenji
中科院分区：
文献类型：
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作者：
Miyake, Junpei;Mochizuki, Takashi;Miyatake, Kenji
为了阐明亲水组分对芳香族离聚物性能的影响，我们首次设计了最简单的结构之一，磺基-1，4-亚苯基单元，作为亲水组分。采用改进的镍催化偶联聚合方法，合成了高分子量（分子量为202-240 kDa）的磺化对亚苯基和低聚芳醚砜酮的芳香离聚物，并制得了坚韧、柔韧的膜。芳香族离聚物膜显示出良好的亲水/疏水相分离。与我们之前含有磺酸化二苯甲酮基团作为亲水组分的芳香族离聚物膜的比较表明，简单的磺基亚苯基结构（即，亲水性组分中没有极性基团如醚、酮或砜基团）对于膜性能的改善是有效的，即，降低的吸水率和在潮湿条件下优异的机械稳定性。此外，由于高的局部离子交换容量（IEC），简单的结构导致高的质子传导率，特别是在低湿度（高达约100 ℃）下。7.3 mS/cm，在80 ℃和20% RI-I下），这是迄今为止报道的最高值之一。改进的性能的膜也证实了在操作燃料电池。
To elucidate the effect of the hydrophilic component on the properties of aromatic ionomers, we have designed for the first time one of the simplest possible structures, the sulfo-1,4-phenylene unit, as the hydrophilic component. A modified Ni-mediated coupling polymerization produced the title aromatic ionomers composed of sulfonated p-phenylene groups and oligo(arylene ether sulfone ketone)s, as high-molecular-weight polymers (M-W = 202-240 kDa), resulting in the formation of tough, flexible membranes. The aromatic ionomer membranes showed well-developed hydro-philic/hydrophobic phase separation. Comparison with our previous aromatic ionomer membrane containing sulfonated benzophenone groups as a hydrophilic component revealed that the simple sulfophenylene structure (i.e., no polar groups such as ether, ketone, or sulfone groups in the hydrophilic component) was effective for the improvement of the membrane properties, i.e., reduced water uptake and excellent mechanical stability under humidified conditions. Furthermore, because of the high local ion exchange capacity (IEC), the simple structure led to high proton conductivity, especially at low humidity (reaching up to ca. 7.3 mS/cm at 80 degrees C and 20% RI-I), which is one of the highest values reported thus far. The improved properties of the membranes were also confirmed in an operating fuel cell.