In the past two decades, this quantity was investigated The characteristics of capillary waves on the surface of aqueous many times theoretically (1-6) and was determined experisolutions of dimethylalkyl phosphine oxides have been measured mentally (5-10). An overview is given, for example, in as a function of frequency and surfactant concentration. The (11). However, attention was paid mostly to comparatively damping coefficient for solutions of dodecyldimethyl phosphine simple systems, such as, solutions of surfactants at concenoxide increased with concentration, passed through a local maxitrations below the CMC (1-4, 6-9), elastic and viscoelastic mum below the CMC, and was independent of concentration above insoluble monolayers (2, 4, 10), and systems containing the CMC. For solutions of decyldimethyl phosphine oxide, a secmixtures of insoluble and soluble surfactants (4, 5).
ond maximum is observed at the CMC and the damping decreases
Although micellar solutions are more interesting from the considerably in the micellar region. This effect can be explained by an influence of the micellization kinetics on the dynamic surface point of view of applied problems, information about dyelasticity and was not observed earlier for solutions of nonionic namic surface properties in this region in general, and inforsurfactants. The results are used to calculate the characteristic mation about the dynamic surface elasticities at concentratime of the slow step of the micellization process. α§ 1997 Academic tions above the CMC, in particular, are relatively scarce Press (12). The dynamic surface elasticity of micellar solutions Key Words: capillary wave damping; surface rheology; nonionic was first determined by Lucassen (13). However, the develsurfactants; exchange of matter; micelles.
oped theory was based on a simplified single-step model of the micellization process. A more elaborate theory based on the two-step model of Aniansson and Wall (14) and takes