SURFACE VISCOELASTICITY OF A FOAM-FORMING SOLUTION

Surface light scattering has been used to study the propagation of the rmally excited capillary waves on the surface of a complex solution of anionic surfactants. The data suggest that some process or processes act to reduce the damping of the dilatational waves coupled to the cap illary waves. Various aspects of the results are inconsistent with the generally accepted model of free diffusional exchange of amphiphile m olecules between the bulk solution and surface, a barrier to adsorptio n apparently playing a role in these effects. Furthermore, the transve rse shear viscoelastic modulus of the absorbed surface film exhibits r elaxation as a Maxwell fluid, in a similar manner to various insoluble monolayers.