Studies on Phase Behavior of CTAB/Octane/1-Butanol/Water microemulsion

摘要

Quaternary microemulsion of a cationic surfactant (cetyltrimethylammonium bromide, CTAB), octane, water, and 1 - butanol has been investigated using conductivity and pulsed field gradient spin - echo NMR measurements. Conductivity and self - diffusion measurements were found to be self - consistent. In this system, the conductivity behavior has a distinct percolative phenomenon and a bell - shaped curve, which indicates that the single - phase microemulsion phase changes continuously from water - in oil microemulsion via bicontinuous microemulsion to oil - in - water microemulsion with increasing water contents. At the corner of the 1 - butanol, water molecules have a rapid diffusion because the solubility of water in 1 - butanol is relatively large. The self - diffusion coefficient of 1 - butanol is larger than that of octane in the oil - in - water microemulsion do-main due to the same reason.