ELECTRIC-CONDUCTIVITY ANALYSIS OF MICELLAR SOLUTION OF SODIUM DODECYL-SULFATE

Electric conductivities at 298.2 K of sodium dodecyl sulfate solution above the cmc were analyzed from the concentrations of counterion, sur factant ion, and micelle based upon the mass action model of monodispe rse micelle formation, where the three micellization parameters (log K (n) = 230, n = 64, and m = 46.7) were employed. The ionic conductivity of micelle was found to be inconsistent not only with the micellar si ze of the identical charge but also with the conductivity of the dynam ic radius of micelle of the identical charge. The inconsistencies coul d be solved by the hopping reaction of counterions between micelles th rough the overlapping of ionic diffuse double layers around micelle th at takes place when two micelles come close together. The hopping reac tion was found to start when the distance between micelles becomes les s than 5 times the Debye length.