EFFECT OF COUNTERION COMPETITION ON MICELLAR GROWTH HORIZONS FOR CETYLTRIMETHYLAMMONIUM MICELLAR SURFACES : ELECTROSTATICS AND SPECIFIC BINDING

摘要: Counterion-mediated micellar growth for cetyltrimethylammonium 2,6-dichlorobenzoate alone and together with chloride has been investigated using small-angle scattering techniques. Variations in counterion composition at constant ionic strength cause large changes micelle size. The selectivity coefficient adsorption of the aromatic over ions CTA+ surfaces determined. effects two counterions on surface potentials, 1H NMR chemical shift data, allow inferences to be drawn about penetration into head group region micelles. ion increases surfactant-packing parameter by both increasing average volume per surfactant monomer, a cosurfactant-like effect, decreasing area screening electrostatic repulsions. Counterions such as chloride, which show only adsorption, affect are much less effective driving micellar...