Acta Phys. -Chim. Sin. ›› 2007, Vol. 23 ›› Issue (06): 921-925.doi: 10.3866/PKU.WHXB20070624

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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

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

MSC2000: 

  • O642