Dynamic surface tension and adsorption mechanisms of surfactants at the air–water interface

Recent advances in understanding dynamic surface tensions (DSTs) of surfactant solutions are discussed. For pre-CMC solutions of non-ionic surfactants, theoretical models and experimental evidence for a mixed diffusion-kinetic adsorption mechanism are covered. For micellar solutions of non-ionics, up to approximately 100 x CMC, the DST behaviour can also be accounted for using a mixed mechanism model. Finally, the first reported measurements of the dynamic surface excess Gamma(t), using the overflowing cylinder in conjunction with neutron reflection, are described.