阴离子表面活性剂在油水界面聚集的分子动力学模拟

Molecular Dynamics Simulation of Anionic Surfactant Aggregation at the Oil/Water Interface

用分子动力学方法模拟了油、水和阴离子表面活性剂组成的混合溶液从初始"均相"到"油水两相"分离的动力学过程,研究了十二烷基苯磺酸钠(SDBS)在界面分离过程中的作用.模拟发现,油水两相能够在短时间内分离达到平衡,形成一个明显的油水界面;在SDBS存在情况下,油水界面的分离时间随着SDBS浓度的增加逐渐增加,达到平衡时SDBS会在界面处形成一个明显的界面膜,并对油水界面处的水分子有限制作用.模拟表明,分子动力学方法可以作为实验的一种补充,为实验提供必要的微观分子结构信息.

We performed molecular dynamics （MD） simulations to investigate the demixing process of a three-component system, i.e., oil, water, and an anionic suffactant from the initial ＂homogeneous phase＂ to ＂two separated phases＂ and the effect of sodium dodecyl benzene sulfonate （SDBS） in this process was investigated. The two oil/water phases reached equilibrium in a short simulation time and an evident oil/water interface was formed. In the presence of SDBS the separation time of oil and water gradually increased as the concentration of SDBS increased and SDBS formed an evident interface membrane when the system reached equilibrium. Simulation results show that the MD method can be used as an adjunct and can provide the necessary information for experiments on the microstructural properties of molecular structures.