物理化学学报 >> 2015, Vol. 31 >> Issue (1): 83-89.doi: 10.3866/PKU.WHXB201411191

理论与计算化学 上一篇    下一篇

抗衡离子对硫酸盐表面活性剂气/液界面性质影响的分子动力学模拟

胡松青1, 纪贤晶1, 范忠钰2, 张田田1, 孙霜青1   

  1. 1. 中国石油大学华东理学院, 山东 青岛 266580;
    2. 华北油田公司勘探开发研究院, 河北 任丘 062552
  • 收稿日期:2014-10-14 修回日期:2014-11-19 发布日期:2014-12-25
  • 通讯作者: 胡松青 E-mail:ccupc@163.com
  • 基金资助:

    国家自然科学基金(51201183), 山东省优秀中青年科学家基金(BS2013CL033)和中国石油科技创新基金(2011D-5006-0202)资助项目

Counterion Effects on the Properties of Sulfate Surfactants at the Air/Liquid Interface by Molecular Dynamics Simulation

HU Song-Qing1, JI Xian-Jing1, FAN Zhong-Yu2, ZHANG Tian-Tian1, SUN Shuang-Qing1   

  1. 1. College of Science, China University of Petroleum(East China), Qingdao 266580, Shandong Province, P. R. China;
    2. Exploration and Development Research Institute, Huabei Oilfield Company, Renqiu 062552, Hebei Province, P. R. China
  • Received:2014-10-14 Revised:2014-11-19 Published:2014-12-25
  • Contact: HU Song-Qing E-mail:ccupc@163.com
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (51201183), Promotive Research Fund for Excellent Young and Middle-Aged Scientists of Shandong Province, China (BS2013CL033), and CNPC Innovation Foundation, China (2011D-5006-0202).

摘要:

采用全原子分子动力学方法研究了抗衡离子为第一主族离子(Li+、Na+、K+、Rb+和Cs+)的十二烷基硫酸盐表面活性剂的气/液界面性质. 通过分析体系中各组分的密度分布曲线, 考察表面活性剂单分子层在界面的聚集形态, 并利用径向分布函数分析了表面活性剂极性头基与抗衡离子间的相互作用. 研究结果表明: 随着抗衡离子半径的增大, 不同体系的界面水层厚度依次增加, 表面活性剂极性头基与抗衡离子形成的Stern和扩散层厚度也相应增加. 但表面活性剂吸附层的抗衡离子缔合度以及体系表面张力却随抗衡离子半径的增大而减小. 研究表明抗衡离子的差异对十二烷基硫酸盐表面活性剂气/液界面性质有很大影响.

关键词: 十二烷基硫酸盐, 抗衡离子, 气/液界面, 双电层, 分子动力学

Abstract:

Molecular dynamics (MD) simulations have been carried out to study the micro-interfaces between counterions (Li+, Na+, K+, Rb+, Cs+) and dodecyl sulfate surfactant at the air/liquid interface. The morphology of the monolayer was analyzed by the density profile of the surfactant components, and the interactions between the polar head groups of the surfactants and the counterions were analyzed using the radial distribution function (RDF). The results showed that the interfacial thickness and thicknesses of the Stern and diffusion layers increased as the radius of counterion increased, whereas the surface tension and the degree of counterion association at the adsorbed layer decreased as the radius increased. These results indicated that the different counterions had a significant effect on the adsorption behavior of the dodecyl sulfate surfactants at the interface.

Key words: Dodecyl sulfate, Counterion, Air/liquid interface, Electrical double layer, Molecular dynamics

MSC2000: 

  • O641