Dependence of electroosmosis on polymer structure in proton exchange membranes
Dependence of electroosmosis on polymer structure in proton exchange membranes
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DOI：
10.1299/mej.17-00054
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发表时间：
2017-01-01
影响因子：
0.5
通讯作者：
Tokumasu, Takashi
中科院分区：
文献类型：
--
作者：
Mabuchi, Takuya;Tokumasu, Takashi
使用反应分子动力学模拟研究了聚合物结构对质子交换膜 (PEM) 电渗的影响。非和谐二态经验价键 (alpha TS-EVB) 模型已被用来描述通过 Grotthuss 跳跃机制有效地过量质子传输。电渗阻力系数（即每个质子通过膜传输的水分子数量）已在由各种当量重量 (EW) 组成的 PEM 中直接评估。 MD 模拟的电渗阻力系数与所研究的水合水平下的可用实验值非常一致。结果表明，对于低含水量，水团簇的连通性随着电波的增加而降低，导致电渗阻力系数降低。由于水簇域的结构变化，质子和水的迁移率也随着电子波的增加而降低。目前的模拟提供了有关不同聚合物结构中电渗和纳米级水域结构之间直接联系的定量信息
Effects of polymer structure on the electroosmosis in proton exchange membranes (PEMs) have been investigated using a reactive molecular dynamics simulation. An anharmonic two-state empirical valence bond (alpha TS-EVB) model has been used to describe efficiently excess proton transport via the Grotthuss hopping mechanism. The electroosmotic drag coefficients (i.e., the number of water molecules transferred through the membrane per proton) has been evaluated directly in PEMs consisting of various equivalent weights (EWs). The electroosmotic drag coefficients from the MD simulations are in good agreement with the available experimental values at studied levels of hydration. It is shown that for low water contents the connectivity of the water clusters decreases with increasing EW, leading to a decrease in the electroosmotic drag coefficients. The proton and water mobility is also found to decrease with increasing EW because of the structural changes in the water cluster domains. The present simulations provide quantitative information about the direct link between electroosmosis and nanoscopic water domain structure in different polymer structures