Abstract
In this work, the effect of octane concentration on the phase behavior of CTAB/water/1-butanol system was studied by using pulsed field gradient spin-echo NMR measurements and freeze fracture electron microscopy (Cryo-TEM and FFEM). When the octane concentration increases, the liquid crystalline phase is destabilized and a continuous single-phase microemulsion region from the water apex to the oil apex is formed. The conductivity behavior has a distinct percolative phenomenon, which indicates that the single-phase microemulsion is changed continuously from oil-in-water (o/w) structure via a bicontinuous structure to water-in-oil (w/o) structure. This result is consistent with those of the PGSE-NMR, Cryo-TEM, and FFEM. In the w/o region, the self-diffusion coefficient of water is relatively high ((1–6)×10−10 m · s−1) due to the higher solubility of water in the continuous phase consisting of octane (10% by weight) and 1-butanol. The penetration of a large amount of octane molecules between surfactant chains results in the much lower self-diffusion coefficient of octane.
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Xu, J., Li, G., Zhai, L. et al. A study of the microstructure of CTAB/1-butanol/octane/ water system by PGSE-NMR and Cryo-TEM. Chin. Sci. Bull. 46, 1272–1276 (2001). https://doi.org/10.1007/BF03184323
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DOI: https://doi.org/10.1007/BF03184323