Dielectric Relaxation of Water in Aqueous Solutions of n‐Alkylamine Hydrochlorides Part 2: Solute Concentrations Larger than the Critical Micelle Concentrations

Abstract

AbstractThe solutes are the chlorides of the amphiphilic cations CH3(CH2)n N+ H3 with n = 5, 6, 7, 9 and CH3(CH2)11 N+(CH3)3, which above the critical micelle concentration aggregate to micelles in aqueous solutions. The complex permittivity of the solutions has been measured in dependence of frequency between 5 and 37 GHz at 25°C.From the analysis of the frequency dependence of the complex permittivity, statements are made on the micellar shape and on the microdynamics of the water molecules influenced by the micelles.The micellar shape seems to be ellipsoidal within the high concentrated solutions. There are two species of micellar hydration water. One species is characterized by a very large reorientation time of the molecules. This effect is attributed to the pourous structure of the micellar surface. The reorientation time of the other species is somewhat smaller than the reorientation time of pure water. This is explained by weak electric fields acting near the micellar surface and thus causing negative hydration.