摘要
用分子动力学模拟方法研究外电场(简称电场)作用下水化聚全氟磺酸钾膜中水分子的电渗迁移运动,并分析探讨膜的结构与水分子的电渗迁移特性的关系.结果表明,无外加电场时水分子和K+的速度都服从麦克斯韦分布;施加适当电场时,水分子和K+在垂直电场方向上的速度分量仍服从麦克斯韦分布,但平行电场方向上的速度分量则服从峰值漂移的麦克斯韦分布.并且,峰值漂移速度可作为水分子和K+的平均迁移速度的近似值,从而计算得到水分子的电渗系数.结果还显示,K+第一配位层内平均含有约4.04个水分子,它们的平均迁移速度只有K+的57%.这部分水分子贡献的电渗迁移系数为总电渗迁移系数(2.97)的77%.
The electroosmotic drag and the corresponding mechanism of water molecules in hydrated potassium perfluorosulfonate electrolyte polymer membrane were studied using molecular dynamics simulations,and the relationship between the membrane structure and electroosmotic drag characteristics was analyzed.It is concluded that velocities of both H2O and K＋ obey the Maxwell velocity distribution function without external electric field applied.If an appropriate electric field is applied,the velocities of H2O and K＋ still obey the Maxwell velocity distribution in the direction perpendicular to the electric field,and obey the peak shifted Maxwell velocity distribution in the direction parallel to the electric field.The peak shifting velocities coincide with the average transport velocities of H2O and K＋ induced by the applied electric field,and could be applied to evaluate the electroosmotic drag coefficient of water.The results also show that the average number of water molecules in the first coordination shell of K ＋ is 4.04,and the average transport velocity of these water molecules is about 57% of that of K＋.The electroosmotic drag coefficient contributed by these water molecules is about 77% of total the electroosmotic drag coefficient（2.97）.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
2010年第10期2659-2665,共7页
Acta Physico-Chimica Sinica
基金
国家自然科学基金(20873081)
上海市科委纳米专项(0952nm01300)资助项目~~
关键词
分子动力学模拟
质子交换膜
外电场
电渗迁移
速度分布函数
Molecular dynamics simulation
Proton exchange membrane
External electric field
Electroosmotic drag
Velocity distribution function
