Acta Phys. -Chim. Sin. ›› 2010, Vol. 26 ›› Issue (10): 2659-2665.doi: 10.3866/PKU.WHXB20100934

• ELECTROCHEMISTRY • Previous Articles     Next Articles

Electroosmotic Drag of Water in Hydrated Potassium Perfluorosulfonated Polymer Membrane in External Electric Fields

ZHU Su-Hua1,2,3, YAN Liu-Ming2, JI Xiao-Bo2, SHAO Chang-Le2, LU Wen-Cong2   

  1. 1. College of Material Science and Engineering, Shanghai University, Shanghai 200444, P. R. China;
    2. Department of Chemistry, College of Science, Shanghai University, Shanghai 200444, P. R. China;
    3. College of Physics and Electronic Engineering, Changshu Institute of Technology, Changshu 215500, Jiangsu Province, P. R. China
  • Received:2010-04-29 Revised:2010-06-14 Published:2010-09-27
  • Contact: YAN Liu-Ming E-mail:liuming.yan@shu.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (20873081), and the Nano project of Shanghai Municipal Science & Technology Commission, China (0952nm01300).

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Abstract:

The electroosmotic drag and the corresponding mechanism of water molecules in hydrated potassiumperfluorosulfonate electrolyte polymer membrane were studied using molecular dynamics simulations, and therelationship between the membrane structure and electroosmotic drag characteristics was analyzed. It is concluded thatvelocities of both H2O and K+ obey the Maxwell velocity distribution function without external electric field applied. Ifan appropriate electric field is applied, the velocities of H2O and K+ still obey the Maxwell velocity distribution in thedirection perpendicular to the electric field, and obey the peak shifted Maxwell velocity distribution in the directionparallel 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. Theresults also show that the average number of water molecules in the first coordination shell of K + is 4.04, and theaverage transport velocity of these water molecules is about 57% of that of K +. The electroosmotic drag coefficientcontributed by these water molecules is about 77% of total the electroosmotic drag coefficient(2.97) .

Key words: Molecular dynamics simulation, Proton exchange membrane, External electric field, Electroosmotic drag, Velocity distribution function

MSC2000: 

  • O646