分子动力学模拟电解质对阴非离子表面活性剂界面行为的影响

Effect of Electrolytes on the Interfacial Behavior of Nonionic-Anionic Surfactant Solutions Using Molecular Dynamics Simulations

通过分子动力学(MD)方法研究了不同类型电解质对阴非离子表面活性剂C_(12)EO_3C油水界面性能的影响。运用z轴质量密度分布、径向分布函数、分子间相互作用配位数、空间分布函数及均方根位移五种模拟参数来分析电解质与阴非离子表面活性剂的相互作用情况。研究表明,三种离子的加入均对水分子与表面活性剂亲水基形成的水化层结构产生影响,且从微观层面验证三种离子对表面活性剂亲水基相互作用强度大小顺序为Na^(+)<Ca^(2+)+<Mg^(2+)。通过扩散模拟结果可以较好地解释离子加入对界面张力平衡时间的影响情况。这对指导实验方向、制订最佳复配方案具有重要意义。

The effect of electrolytes on the interfacial behavior of nonionic-anionic surfactant solutions is studied using molecular dynamics（MD） simulations. The z-dependent surfactant density, radial distribution, coordination number, spatial distribution function, and mean-squared displacement are used to analyze the interaction of electrolytes and surfactants. Based on our simulated results, the three counter ions Na^＋, Ca^2＋, and Mg^2＋＋have an effect on the hydration shell structure. On a micro level, the binding strength of the Na^2＋＋counter ion is less than Ca^2＋, which is less than Mg^2＋, and this simulated result is consistent with the experimental results. The diffusion results can explain the interfacial tension（IFT） equilibrium time and have a significant effect on the optimal mixture method.