Dielectric Spectra of Aerosol OT/Water Systems at Different Concentrations and Temperatures

Abstract

Abstract: The dielectric spectra of aerosol OT[AOT, sodium(bis-2-ethylhexyl)sulfosuccinate]/water systems at different concentrations and temperatures were investigated by the dielectric relaxation spectroscopy(DRS). Through the dielectric spectra of different concentrations, two dielectric relaxations were observed over a frequency range from 40 Hz to 110 MHz and the mechanisms of the relaxations were also interpreted based on the Grosse’s model. The low-frequency relaxation(around 105 Hz) was attributed to the radial diffusion of counterions along the long-half axis of the rod-like micelle, and the high-frequency relaxation(around 106 Hz) was ascribed to the radial diffusion of counterions along the short-half axis. Furthermore, specific emphasis was placed on studying the effects of temperature on system’s conductivity. It was observed that the low-frequency limit of conductivity(κl) decreased and then increased with the increment of temperature under the measured concentration. On the other hand, the conductivity(κm and κh) in meso- and high-frequency ranges always increased as temperature increased. Both the tendencies of alteration which mentioned above should be related to the phase transition of AOT/water system.

Key words: Aerosol OT, Rod-like micelle, Dielectric relaxation spectroscopy

ZHAO Kong-shuang*, JIA Zhan-jie, YANG Li-kun and XIAO Jin-xin. Dielectric Spectra of Aerosol OT/Water Systems at Different Concentrations and Temperatures[J]. Chemical Research in Chinese Universities, 2011, 27(6): 1065-1071.

References

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