物理化学学报 >> 2007, Vol. 23 >> Issue (06): 921-925.doi: 10.3866/PKU.WHXB20070624

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DMA+AOT+正辛烷三组分非水微乳体系的临界现象

蔡红兰; 安学勤; 沈伟国   

  1. 兰州大学化学化工学院, 兰州 730000; 南京师范大学化学与环境科学学院, 南京 210097; 华东理工大学化学系, 上海 200237

  • 收稿日期:2006-12-19 修回日期:2007-01-15 发布日期:2007-06-04
  • 通讯作者: 安学勤 E-mail:anxueqin@163.com

Critical Phenomena of Three-component Nonaqueous Microemulsion Systemof DMA+AOT+n-octane

CAI Hong-Lan; AN Xue-Qin; SHEN Wei-Guo   

  1. College of Chemistry&Chemical Engineering, Lanzhou University, Lanzhou 730000, P. R. China; College of Chemistry and Environment Science, Nanjing Normal University, Nanjing 210097, P. R. China; Department of Chemistry, East China University of Science and Technology, Shanghai 200237, P. R. China

  • Received:2006-12-19 Revised:2007-01-15 Published:2007-06-04
  • Contact: AN Xue-Qin E-mail:anxueqin@163.com

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摘要：

采用折射率法在离临界温度7 K的范围内测定N,N-二甲基乙酰胺(DMA)与二-(2-乙基己基)琥珀酸酯磺酸钠(AOT)摩尔比为3.46的非水微乳体系(DMA+AOT+正辛烷)的温度-折射率(T-n)共存曲线, 利用标准曲线转化为温度-体积分数(T-φ)共存曲线和温度-有效体积分数(T-ψ)共存曲线, 进而求得临界指数β. 研究结果表明, 该体系的临界指数β与已经报道的微乳液不同, 在较宽的温度范围内均符合Fisher重整化理论值0.365. 分析实验数据, 获得指数因子B、Wegner校正项因子B1和共存曲线的直径籽d, 并讨论所选择的序参量的优劣性.

关键词: 微乳液, 临界现象, 共存曲线, 折射率, AOT

Abstract:

The coexistence curves of (T-n) (T and n are temperature and refractive index, respectively) for the system of DMA+AOT+n-octane have been determined within about 7 K from the critical temperature (Tc) by measurements of refractive index at a constantmolar ratio of DMAto AOT (3.46). The coexistence curves of (T-n) have been converted to the coexistence curves of (T-φ) and (T-ψ) (φand ψare volume fraction and effective volume fraction, respectively) through the standard curves determined by measurements of refractive indexes at various volume fractions and temperatures. The critical exponent β was deduced from the coexistence curves, which was found to be inconsistent with the 3D-Ising value and approach the Fisher-normalization value 0.365 in a rather wide temperature range. The experimental results were also analyzed to obtain the critical amplitude B and the Wegner correction terms B1 to examine the diameters of coexistence curves, and to discuss the goodness of the order parameter.

Key words: Microemulsion, Critical phenomena, Coexistence curve, Refractive index, AOT