ELECTROCHEMICAL STUDY ON STRUCTURAL CONVERSION OF SODIUM DODECYL SULFONATE MICROEMULSION

A phase diagram of the pseudoternary sodium dodecyl sulfonate butanol heptane water (C 12 H 25 SO 3Na C 4H 9OH C 7H 16 H 2O) system at k m=W(C 4H 9OH)/W(C 12 H 25 SO 3Na)=2 was obtained.The diffusion coefficients of microemulsion with initial oil content 21%(wet%) were measured by using ferrocene (Fc) and potassium ferricyanide [K 3Fe(CN) 6] as the electroactive probes by cyclic voltammetric measurement.The structural conversion of microemulsion has been determined from water content dependence of the diffusion coefficient in one phase microemulsion region.A water in oil microemulsion (W/O) was formed when the sater content is lower (20% to 45%).At high water content (65%),and oil in water microemulsion (O/W) is stable.When the water content is within about 45% to 65% range,however,a bicontinuous structure of microemulsion was found.The electrical conductivity datum supported the results of cyclic voltammetric measurements.