Viscosity behavior of cationic gemini surfactants with long alkyl chains

Viscosity experiments were carried out on aqueous micellar solutions of the cationic gemini surfactants as a function of surfactant concentration, aging time, temperature and shear rate. The viscosity behavior of cationic gemini surfactants in dilute solution is closely related to the alkyl chains and spacer groups of gemini surfactants. The viscosities of some gemini surfactants solutions vary with aging time, such as 16-4-16 and 18-4-18. For 12-2-12, the viscosity of solution decreases with the increase of temperature. But for series of 16-s-16 and 18-s-18 with s=2 or 3, the viscosity variations of them are particularly unusual with the increasing of temperature, which increase at first, then reach a peak and decrease in the end. The effect of shear rate on the micellar solution of 22-4-22 was investigated and shear-induced thickening was not observed at the experimental shear rate ranges. (C) 2004 Elsevier B.V. All rights reserved.