Viscosity and quasielastic light scattering study of micellar solutions of hexadecyltrimethyl ammonium bromide in presence of 0.1 M KBr

Abstract

Micellar solutions of hexadecyltrimethyl ammonium bromide (CTAB) solutions in M₂O-0.1M KBr have been investigated by quasielastic light scattering and viscosity. In order to measure the zero shear viscosity and the longest relaxation time was used a magnetorheometer. The measurements were performed as a function of temperature (30° to 60°C) and surfactant concentration (10⁻³M to 0.84M). The results are consistent with a model of long flexible micelles described elsewhere. In the semi-dilute range, the elastic modules is nearby constant, at given surfactant concentration, when the temperature is increased, whereas the viscosity and the relaxation time decrease markedly. In this range, the behavior can be qualitatively described using an analogy with an entagled network of polymer chains.