Influence of NACL on the Micellar Behaviour of Some Cationic Surfactans

Abstract

An attempt has made to study the influence of NaCl on the micellar behaviour of some cationic surfactants by conductivity measurements. With increase in concentration of salt, the critical micelle concentration (CMC) of cetyltrimethylammoniumbromide (CTABr) decreases. For example, the CMCs of CTABr in 0.5,1, 2.5 and 5mM solutions of NaCl were 0.95, 0.89, 0.70, 0.51 respectively. The degree of dissociation i.e. β and Gibbs free energy of micellization, ΔG o mic, was also determined for each CMC value.