Molecular Dynamics Simulations of SDS, DTAB, and C12E8 Monolayers Adsorbed at the Air/Water Surface in the Presence of DSEP

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• 作者：Jinyu Pang ; Yajing Wang ; Guiying Xu ; Tingting Han ; Xin Lv ; Jian Zhang
• 刊名：Journal of Physical Chemistry B
• 出版年：2011
• 出版时间：March 24, 2011
• 年：2011
• 卷：115
• 期：11
• 页码：2518-2526
• 全文大小：1202K
• 年卷期：v.115,no.11(March 24, 2011)
• ISSN：1520-5207

文摘

The properties of adsorbed monolayers of three hydrocarbon surfactants with the same hydrophobic tail, sodium dodecyl sulfate (SDS), dodecyltrimethylammonium bromide (DTAB) and octaethylene glycol dodecyl ether (C₁₂E₈) at the air/water surface in the absence and presence of a dimethylsiloxane ethoxylate-propoxylate (DSEP) were studied via molecular dynamics simulations to compare the effect of the headgroups on the aggregation behaviors of surfactant mixtures. The structures and dynamical properties of the monolayers were greatly affected after adding DSEP. In the presence of DSEP, SDS monolayer was better ordered and more compact, whereas C₁₂E₈ monolayer was relatively disordered. Some DTAB molecules immerged into water, and the others adsorbed at the surface were in less compact but well-ordered arrangement. The reason for the appearance of different types of monolayers was also discussed, with the goal of providing a theoretical approach for their further applications.