Abstract
The surface tension of aqueous solutions of dodecyldimethylammonium chloride has been measured as a function of surfactant concentration at different NaCl concentrations. By an analysis of the Gibbs' adsorption isotherm, the surface excesses of surfactant ions, counter ions (Cl −), and coions (Na +) are estimated at different surfactant and NaCl concentrations. The adsorption isotherm of the surfactant ion approximately follows the Langmuir isotherm, having the saturated adsorption around (4 ∼ 6) × 10 −10 mole cm 2, while the adsorption of Na + is negligibly small at low NaCl concentrations. The structure of the aqueous surface, composed of a charged monolayer and a diffuse double layer, is discussed with reference to the Gouy model of electric double layer.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have