The influence of cationic surfactants on rheological properties of bentonite-water systems

The influence of surfactants on the flow behaviour of bentonite-water syste ms (2% w/w) was studied for two cationic surfactants, cetyltrimethylammoniu m bromide (CTAB) and distearlydimethylammonium chloride (DDAC), in the rang e of 10(-5)-10(-2) mol/l. These surfactants were added to Ca- and Na-benton ite-water systems in seven different concentrations and the observed result was the different effects on the viscosity, which is related to the intera ctions between particles and surfactant, particles and particles, and parti cles and water molecules. The adsorption of cationic surfactant on a charge d surface leads to significant modification of the charge distribution in t he electrical double layer, and, thus, in the interaction of particles with each other. (C) 2000 Elsevier Science B.V. All rights reserved.