Hexyltrimethylammonium bromide solutions at 278.15: A dielectric investigation on micelle relaxation and hydration

Abstract

Abstract A low temperature, 278.1 K studies on the dynamics of micelles and its hydrophilic and hydrophobic hydration of n-hexyltrimethylammonium bromide solutions is studied by dielectric measurements. The covered frequency range was ∼ 0.2 to 89 / GHz and concentration was varied from 0.0982 to 0.8534 mol.dm-3. A sum of four Debye processes fits all the spectra. Micelle relaxation processes are observed below the critical micelle concentration indicating premicellar aggregation. The relaxation processes were analyzed with theory proposed by Grosse. Accordingly the two low frequencies are assigned to radial and tangential diffusion of free and bound counter ions around the charged micelles. It is revealed that the hydrophilic hydration where the water molecules are completely immobilized is independent of temperature. On the other hand, the hydrophobic hydration increases at lower temperature.