Original Articles
Geetha Sarasan
Abstract
Krafft Temperature determination for cationic surfactant Cetylpyridinium bromide(CPBr )had done in aqueous and 5%, 10%, 15% & 20% Ethylene Glycol-water systems. To study the krafft temperature, conductance measurements were used and the concentration of Cetylpyridinium bromide taken is above its CMC value. The temperature at which the values of conductance have an abrupt change is considered as the Krafft Temperature .There are two changes in the slope of the line is observed in the plots of specific conductance versus temperature in all the cases studied. The first slope change is highly abrupt compared to the second one. This interesting observation indicates the formation of premicellar aggregates of Cetylpyridinium bromide before attaining the Critical Micelle Concentration in aqueous and in mixed solvent systems of ethylene glycol and water which support the previous finding of premicellar aggregates formation during CMC determination. The author has previously reported the micellization of Cetylpyridinium bromide in aqueous and in mixed solvent systems of ethylene glycol and water. Again, it is observed that the krafft temperature of Cetylpyridinium bromide in aqueous medium is less than that of it in the mixed solvent systems of ethylene glycol and water.