STUDIES ON MICELLE FORMATION AND ENTHALPY OF MICELLIZATION IN MOLTEN ACETAMIDE

The electrical conductivity of lithium dodecylsulfate, sodium dodecylsulfate, sodium oleate and sodium stearate has been determined in molten acetamide at 90 degrees C. Conductivity measurements show that for these surfactants, micelles are formed in molten acetamide solutions. The critical micelle concentration (CMC) of each surfactant has been calculated. Lithium dodecylsulfate has a lower CMC than sodium dodecylsulfate. Sodium oleate, which contains a double bond and has the same number of carbon atoms as sodium stearate, has a lower CMC. The enthalpy of micellization for sodium oleate in molten acetamide has been found by determining the CMC at different temperatures. The results have been explained on the basis of solvation effect and nature of micelles.