Dynamic surface properties of aqueous cetyltrimethylammonium bromide solutions at air/liquid interface

Dynamic surface tensions of the aqueous cetyltrimethylammonium bromide solu tions were measured by the maximum bubble pressure method at different conc entrations as a function of temperature, from 20 to 40 degreesC. The dynami c adsorption T calculated from data of the dynamic surface tension, obeys d ynamic surface state equation obtained from the Henry adsorption isotherm a t concentrations below 0.10 mol (.) m(-3), and the dynamic adsorption can b e described by the dynamic surface state equation derived from the Langmuir isotherm in the concentration range 0.10 similar to 0.80 mol (.) m(-3). Th e surface adsorption of cetyltrimethylammonium bromide molecules at air/liq uid interface obeys the mixed adsorption kinetics at the later stage of ads orption. By using the values of the apparent diffusion coefficients, the ad sorption barrier was estimated as between 6.7 and 7.1 kJ (.) mol(-1). The p ossible factors causing the adsorption barrier were also analyzed qualitati ve.