Electrical properties of aqueous solutions of hexyl- and decyl-trimethylammonium bromides

Abstract

The critical micelle concentrations of hexyl- and decyl-trimethylammonium bromides in aqueous solution have been estimated from the concentration dependence of their electrical conductivities. Only for salt concentrations above the c.m.c. are two distinct dispersions of permittivity observed in dielectric relaxational studies of these solutions. The relaxation time and amplitude of the lower-frequency dispersion, which has been attributed to a frequency-dependent surface admittance of the cationic micelles present, both vary with salt concentration in a complicated manner. The dielectric behaviour of the bulk solvent has been discussed in terms of the effect of the micelles on the structure of the solvent in their immediate vicinity.