Dissipative Particle Dynamics Simulation of Phase Behavior of Aerosol OT/Water System

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• 作者：Chunjie Yang ; Xiao Chen ; Huayu Qiu ; Wenchang Zhuang ; Yongcun Chai ; Jingcheng Hao
• 刊名：Journal of Physical Chemistry B
• 出版年：2006
• 出版时间：November 2, 2006
• 年：2006
• 卷：110
• 期：43
• 页码：21735 - 21740
• 全文大小：715K
• 年卷期：v.110,no.43(November 2, 2006)
• ISSN：1520-5207

文摘

The phase behaviors of the binary mixture of an anionic surfactant aerosol OT (AOT) and water are investigatedon a mesoscopic level using dissipative particle dynamics (DPD) computer simulations. With a simple surfactantmodel, various aggregation structures of AOT in water including the lamellar, viscous isotropic, and reversehexagonal phases are obtained, which agree well with the experimental phase diagram. Special attention isgiven on the unusual lamellar regions. Water diffusivity shows much useful information to understand howthe phase behaviors varied with concentration and temperature. It is proposed that the anomalous lamellarphenomena at intermediate AOT concentration (about 40%) are due to the formation of a defective structure,pseudoreversed hexagonal phase, which evidently decreases the water diffusivity. After increasing temperatureabove 328 K, the pseudoreversed hexagonal structure will be partly transformed to a normal lamellar phasestructure and the system lamellar ordering is therefore enhanced.