Solubilization of short chain phenylalkanoic acids by a cationic surfactant, cetyltrimethylammonium bromide

The solubilization of short chain phenylalkanoic acids by the aqueous micellar solution of cetyltrimethylammonium bromide (CTAB) has been studied as a function of surfactant concentration. The micelle-water partition coefficient, K-x, and the standard free energy change of solubilization, Delta G(p)(o), of these additives in the CTAB micelles was determined by using both differential spectroscopic and conductance data at 25.0 degrees C. The critical micelle concentration (CMC) of CTAB in the presence of small amount of these additives was determined by conductivity method. The relative solubility and approximate number of additive molecules per micelle was also estimated at a particular concentration of the surfactant. (C) 1999 Elsevier Science B.V. All rights reserved.