标题：Surface behavior of a model surfactant: A theoretical simulation study
作者：Yuan, S.-M.;Yan, H.;Lv, K.;Liu, C.-B.;Yuan, S.-L.
作者机构：[Yuan, S.-M] School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China, East-China Design Institute, CPNC, Qingdao 260100 更多
通讯作者地址：[Yuan, SL]Shandong Univ, Sch Chem & Chem Engn, Jinan 250100, Peoples R China.
来源：Journal of Colloid and Interface Science
关键词：Alkyl benzene sulfonate;Molecular dynamics;Potential of mean force;Surfactant
摘要：A quantum mechanics (QM) method has been used to calculate molecular properties of sodium dodecylbenzenesulfonate (SDBS) in vacuum and in solution. Furthermore, molecular dynamics (MD) simulations have been used to determine the dynamic behavior of SDBS moving from the bulk solution to the air/water interface. QM calculations suggest that two head-group oxygen atoms on each surfactant molecule interact with a Na~+ ion, despite the availability of three oxygen atoms in the head group. MD simulations showed that the Na~+ ion must overcome the energy barrier between two solvent layers around the head group to form stable ion pair in solution, which is consistent with experimental results. In the simulation, in moving from the bulk to the interface, SDBS can aggregate in a short time, and the adsorption adopts a preferred orientation. The results indicate that formation of favorable hydrophobic interactions of the surfactant alkyl chains is the origin of interfacial adsorption of SDBS.