Yan Liuming, Ji Xiaobo, Lu Wencong
Department of Chemistry, College of Sciences, Shanghai University, 99 Shangda Road, Shanghai 200444, China.
J Phys Chem B. 2008 May 8;112(18):5602-10. doi: 10.1021/jp7121449.
An atomistic MD simulation method has been developed to study the electroosmotic drag in the hydrated perfluorosulfonic acid polymer. The transport characteristics of the hydroniums and water molecules are evaluated from their velocity distribution functions with an electric field applied. It is shown that the microstructure of the hydrated perfluorosulfonic acid polymer is not perturbed significantly by the electric field up to 2 V/microm, and the velocity distribution functions obey the peak shifted Maxwell velocity distribution functions. The evaluated peak shifting velocities are only about 1% of the average thermal motion. The hydronium flow and water flow are evaluated from the average transport velocities or the peak shifting velocities. The electroosmotic drag coefficients from the MD simulations are in good correspondence with the experimental values. It is also shown that the electroosmotic drag coefficient has no or weak temperature dependence.
已开发出一种原子分子动力学（MD）模拟方法来研究水合全氟磺酸聚合物中的电渗拖拽现象。通过施加电场时水合氢离子和水分子的速度分布函数来评估它们的传输特性。结果表明，在电场强度高达2V/μm时，水合全氟磺酸聚合物的微观结构不会受到显著扰动，且速度分布函数符合峰值移动的麦克斯韦速度分布函数。所评估的峰值移动速度仅约为平均热运动速度的1%。通过平均传输速度或峰值移动速度来评估水合氢离子流和水流。MD模拟得到的电渗拖拽系数与实验值吻合良好。研究还表明，电渗拖拽系数与温度无关或对温度的依赖性较弱。
