高等学校化学学报2017，Vol.38Issue(10)：1804-1812,9.DOI:10.7503/cjcu20170242
多元体系油水界面上常见表面活性剂行为的分子动力学模拟
Molecular Dynamics Simulation on Behavior of Common Surfactants at the Oil/Water Interface in Complex Systems
摘要
Abstract
In order to explore the behavior of common surfactants on oil/water interface in complex systems, five models were designed to study using the molecular simulation method. Except a blank model, four different surfactants were placed in the same complex systems as follows: sodium dodecyl benzene sulfonate ( SDBS) , dodecyltrimethylammonium bromide( DTAB) , nonylphenol ethoxylates( NPE) , and betaine. These four surfactants represented the anionic surfactant, the cationic surfactant, the nonionic surfactant, and the zwitterionic surfactant, respectively. For these models, radial distribution function(RDF) of surfactants and the oil molecules, mean square displacement( MSD) along z direction of oil molecules, oil/water interfacial tension( IFT) , interaction energy between the oil layer and the mineral stone layer, the distribution of relative concentration of oil molecules along z direction, etc. were analyzed. For the SDBS, NPE, Betaine system, at the beginning, the surfactants arranged regularly at the interface of oil/water, the lipophilic parts of the surfactants were partially inserted into the oil phase, the hydrophilic parts were stretched into the water phase. Then the hydrophilic parts of the surfactants got together and formed to a micelle gradually. The micelle, which of its interior is hydrophilic and its exterior is lipophilic, moved to the oil layer gradually. For DTAB, at first, the surfactants were distributed regularly at the interface of oil/water, they gradually became disorderly as the simulation time increased. But the lipophilic head stretched into oil phase and the hydrophilic head distributed at the oil/water from the beginning to end. The order of the interaction between surfactants and oil molecular were: Betaine≈DTAB<SDBS<NPE; The order of oil displacement efficiency of different surfactants were:Betaine>SDBS>NPE>DTAB>None. Above all, the model systems constructed were rationalized. The results obtained from the simulation were agreement with the experimental data. The research gave partly the illustration of actual oil displacement efficiency of different surfactants at the molecular level.关键词
分子动力学/油水界面/界面张力/相互作用/洗油效果Key words
Molecular dynamics/Oil/water interface/Interfacial tension/Interaction/Oil displacement efficiency分类
化学化工引用本文复制引用
江蓉君,罗健辉,白瑞兵,江波,周歌..多元体系油水界面上常见表面活性剂行为的分子动力学模拟[J].高等学校化学学报,2017,38(10):1804-1812,9.基金项目
中国石油天然气股份有限公司科学研究与技术开发项目(批准号:2014A-1001)资助.Supported by the China National Petroleum & Gas Corporation Science and Technology Development Project( No.2014A-1001) . （批准号:2014A-1001）
