摘要
采用分子动力学的方法研究了阴离子表面活性剂十六烷基苯磺酸盐在正十六烷-水界面上的聚集结构,研究了苯环在碳氢链上的取代位置对油水界面性质的影响。由界面生成能和界面层厚度的计算结果可知,苯磺酸盐接在十六烷第2个碳上体系从能量上最稳定,界面厚度最大;不同体系的分子占有面积和分子构象参数决定了不同表面活性剂界面单层膜排列情况。研究结果表明,对于较大碳数烷烃,支链烷基苯磺酸盐结构的影响主要来自于尾链的构象排布,苯环的取代位置越靠近碳链端点,分子占有面积越小,在界面上的吸附能力越强。表面活性剂分子的伸展性和有序性的增加使界面排布更紧密,更容易达到低界面张力,利于驱油。
The interfacial aggregates of anionic surfactant and hexadecane benzene sulfonate at the hexadecane-water interface were studied by atomistic molecular dynamics simulations, and the effect of the attachment position of benzene sulfonate on the hexadecane backbone was discussed. Depending on the interface formation energy and the interfacial thickness, the 2C16-mediated system, in which the benzene sulfonate group attached to the 2nd carbon in the hexadecane backbone, had the most energetic stable and thickest interface. Furthermore, the arrangement of the surfactant monolayer at the interface was compared in terms of molecular interfacial area and conformational parameters. The re- sults showed that the influence of the structure of branched alkyl benzene sulfonate was mainly attributed to the confor- mational alignment of the lipophilic alkyl tall for larger alkanes. As the substituted position of the benzene ring moved closer to the carbon chain endpoint, the surfactants were aligned with a smaller interfacial area, indicating stronger ad- sorption at the interface. As the extensibility and orderliness of the surfactants molecules increased, the interface ar- rangement compact more closely, which could make the surfactant correlate with a lower interfacial tension for the hexadecane-water interface and could make it easier for oil flooding.
出处
《山东大学学报（工学版）》
CAS
北大核心
2012年第2期77-82,共6页
Journal of Shandong University（Engineering Science）
基金
国家自然科学基金资助项目(21173128)
中石化科研攻关项目(P08017)
关键词
烷基苯磺酸盐
分子动力学模拟
界面性质
分子构象
油水界面
表面活性剂
alkyl benzene sulfonate
molecular dynamics simulation
interfacial properties
molecular conformation
oil-water interface
surfactants
