分子动力学模拟Ca2+对SB12-3/SDBS复配体系在油/水界面聚集行为的影响  

Effect of Ca2+ on Aggregation Behavior of Mixed N-dodecyl-N,N-dimethy-3-ammonio-1-propanesulfonate（SB12-3）/Podium Dodecyl Benzene Sulfonate at Oil/Water Interface: A Molecular Dynamics Study

作　　者：李杰[1] 韩颖[1] 曲广淼[1,2] 程杰成 薛春龙 丁伟[1] LI Jie;HAN Ying;QU Guang-miao;CHENG Jie-cheng;XUE Chun-long;DING Wei(College of Chemistry and Chemical Engineering, Northeast Petroleum University, Daqing 163318, Heilongjiang, China;Nanjing Polytechnic Institute, Nanjing 210048, Jiangsu, China;Daqing Oilfield Limited Company of Petrochina, Daqing 163002, Heilongjiang, China)

机构地区：[1]东北石油大学化学化工学院,黑龙江大庆163318 [2]南京科技职业学院,江苏南京210048 [3]大庆油田责任有限公司,黑龙江大庆163002

出　　处：《精细化工》2018年第6期956-963,共8页Fine Chemicals

基　　金：国家自然科学基金(51674085)~~

摘　　要：采用分子动力学模拟方法对十二烷基磺丙基甜菜碱（SB12-3）/十二烷基苯磺酸钠（SDBS）表面活性剂复配体系在油/水界面的聚集行为进行了考察,在分子水平上讨论了Ca^2＋对SB12-3/SDBS表面活性剂复配体系性质的影响。模拟结果表明：SB12-3与SDBS的物质的量之比为4∶6时两者的协同增效作用最好。Ca^2＋加入后可以取代油/水界面处Na-＋的位置,压缩SB12-3和SDBS的极性头基使两者在油/水界面排布得更紧密。径向分布函数计算结果表明：Ca^2＋存在时SB12-3和SDBS中的—SO3^-与水分子的相互作用更强,Na-＋更加靠近SB12-3的—SO3^-,使其扩散双电层被压缩;同时,SB12-3和SDBS的溶剂可及面积明显减小,使两者在界面排布得更紧密。通过计算疏水尾链序参数以及SB12-3和SDBS的极性头基与疏水尾链之间的角度,发现Ca^2＋可以使SB12-3和SDBS的疏水尾链与油相的相互作用增强,降低油/水界面张力。Molecular dynamics simulation was used to study the aggregation behavior of mixed N-dodecyl-N,N-dimethy-3-ammonio-1-propanesulfonate（SB12-3）/sodium dodecyl benzene sulfonate（SDBS） surfactant system at oil/water interface. The effects of Ca^2＋ on the properties of the mixed surfactant system were investigated from a microscopic point of view. The simulation results showed that the mixed SB12-3/SDBS system with a molar ratio of 4：6 exhibited the best synergistic effects. The additive Ca^2＋ could replace Na-＋at the oil/water interface,which compressed the polarity head groups of SB12-3 and SDBS so that both the surfactants were arranged at oil/water interface more closely. Radial distribution functions indicated that the interaction between —SO3^- in SB12-3 and SDBS and water molecules increased with the addition of Ca^2＋,Na-＋ was closer to —SO3^- in SB12-3,which compressed the thickness of electric double layer. Meanwhile,the solvent accessible surface areas declined obviously in the presence of Ca^2＋. By calculating order parameter and angles between the hydrophilic groups and hydrocarbon chains of SDBS and SB12-3,it was found that Ca^2＋ could enhance the interaction between oil and hydrocarbon chains of SB12-3 and SDBS,and reduce the oil/water interfacial tension.

关 键 词：分子动力学模拟 十二烷基磺丙基甜菜碱 十二烷基苯磺酸钠 复配体系 钙离子 表面活性剂 

分 类 号：O641[理学—物理化学]