DETERMINATION OF THE ZETA-POTENTIAL OF SURFACTANTS WITH MIXED COUNTERIONS USING A VIDEO ENHANCED MICROSCOPY ELECTROPHORESIS CELL

The zeta potential of 2 mM solutions of didodecyldimethylammonium and ditetradecyldimethylammonium surfactants containing a mixture of acetate and bromide are reported. The measuremtns were made using new electrophoretic cells which can be used with a video enhanced microscope. This permits the simultaneous visualization and zeta potential characterization of vesicles and microtobule surfactant solutions. With increasing acetate molar fraction, the zeta potential increases. These results are interpreted in terms of the charge density at the shear plane of the aggregate interface. © 1990 Plenum Publishing Corporation.