The adsorption kinetics of the cationic surfactant dodecyltrimethylammonium
bromide at the air-water interface has been studied by the maximum bubble
pressure method at concentrations below the critical micellar concentration. At
short times, the adsorption is diffusion-limited. At longer times, the surface
tension shows an intermediate plateau and can no longer be accounted for by a
diffusion limited process. Instead, adsorption appears kinetically controlled
and slowed down by an adsorption barrier. A Poisson-Boltzmann theory for the
electrostatic repulsion from the surface does not fully account for the
observed potential barrier. The possibility of a surface phase transition is
expected from the fitted isotherms but has not been observed by Brewster angle
microscopy.Comment: 13 pages, 5 figure