Acta Phys. -Chim. Sin. ›› 2009, Vol. 25 ›› Issue (05): 911-914.doi: 10.3866/PKU.WHXB20090510

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Effects of DMA/AOT Molar Ratio on Critical Behavior of Nonaqueous Microemulsion

CAI Hong-Lan, AN Xue-Qin, ZHU Yin-Yan, LV Hui-Hong, SHEN Wei-Guo   

  1. School of Chemistry and Materials Science, Ludong University, Yantai 264025, Shandong Province, P. R. China; School of Chemistry and Molecular Engineering, East China University of Science &Technology, Shanghai 200237, P. R. China; Jiangsu Key Laboratory of Biofunctional Materials, Nanjing 210097, P. R. China
  • Received:2008-12-10 Revised:2009-01-19 Published:2009-05-04
  • Contact: AN Xue-Qin


Coexistence curves of (T-n) (T and n are temperature and refractive index, respectively) for {N,N-dimethylaccetamide(DMA)/sodiumbis(2-ethylhexyl)sulfosuccinate(AOT)/n-octane} nonaqueousmicroemulsion systems with various molar ratios ωs of DMA to AOT have been determined by the measurement of refractive index. Critical exponents (β) and critical amplitudes (B) were deduced fromcoexistence curves of (T-n). Results show that the critical volume fraction φc {i.e. φ=(VAOT+VDMA)/(VAOT+VDMA+Vn-octane)} increases as ωs decreases, but the critical temperature Tc increases with the increase in ωs. Value of the critical exponent βis independent of ωs and approaches 0.365, which is consistentwith the Fisher-renormalization group theory. System-dependence amplitudes (B) increase almost linearly with the increase in ωs.

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


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