Yang Chunjie, Chen Xiao, Qiu Huayu, Zhuang Wenchang, Chai Yongcun, Hao Jingcheng
Key Laboratory of Colloid and Interface Chemistry, Shandong University, Ministry of Education, Jinan, Shandong, 250100, P R China.
J Phys Chem B. 2006 Nov 2;110(43):21735-40. doi: 10.1021/jp0623692.
The phase behaviors of the binary mixture of an anionic surfactant aerosol OT (AOT) and water are investigated on a mesoscopic level using dissipative particle dynamics (DPD) computer simulations. With a simple surfactant model, various aggregation structures of AOT in water including the lamellar, viscous isotropic, and reverse hexagonal phases are obtained, which agree well with the experimental phase diagram. Special attention is given on the unusual lamellar regions. Water diffusivity shows much useful information to understand how the phase behaviors varied with concentration and temperature. It is proposed that the anomalous lamellar phenomena 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 temperature above 328 K, the pseudoreversed hexagonal structure will be partly transformed to a normal lamellar phase structure and the system lamellar ordering is therefore enhanced.
使用耗散粒子动力学（DPD）计算机模拟在介观水平上研究了阴离子表面活性剂气溶胶OT（AOT）与水的二元混合物的相行为。采用简单的表面活性剂模型，得到了AOT在水中的各种聚集结构，包括层状、粘性各向同性和反六角相，这些结果与实验相图吻合良好。特别关注了异常的层状区域。水扩散系数显示了许多有用的信息，有助于理解相行为如何随浓度和温度变化。研究表明，在中间AOT浓度（约40%）下出现的异常层状现象是由于形成了一种缺陷结构——伪反六角相，这明显降低了水扩散系数。当温度升高到328 K以上后，伪反六角结构将部分转变为正常的层状相结构，从而增强了体系的层状有序性。
