Thermodynamic barrier to micelle formation and breakdown

Refractometric Determination of the Critical Micelle Concentration of Non-Ionic Surface-Active Agents

The critical micelle concentrations (CMC) values of some non-ionic surfactants have been determined by refraction and are compared with the results reported earlier by other methods. The slope values have been calculated below and above the CMC and an equation developed to predict the slope below the CMC for any member of the homologous series. The values appear to conform with those expected theoretically from atomic refraction data.

A phenol-induced structural transition in aqueous cetyltrimethylammonium bromide solution

The effect of phenol on the structure of micellar solution of a cationic surfactant, cetyltrimethylammonium bromide (CTAB) was investigated using viscosity, dynamic light scattering (DLS), small angle neutron scattering (SANS) and nuclear magnetic resonance (NMR) techniques. The relative viscosity and apparent hydrodynamic diameters of the micelles in CTAB solution increase initially and then decrease with addition of phenol. SANS studies indicate a prolate ellipsoidal structure of the micelles. The axial ratio of the prolate ellipsoidal micelles increases and then decreases with addition of phenol, consistently with DLS and viscosity measurements. NMR studies confirm the solubilization of phenol to the palisade layer and growth of the micelles at high concentration of phenol as revealed from the broadening of peaks.