Surfactant-polymer interactions in freely suspended lyotropic films

We present results of an experimental study of surfactant-polymer interactions in free-standing soap films. The relaxation of thermally induced corrugations of the surfactant monolayers comprising a film is studied by reflectivity and light-scattering methods. Our data show that polymers influence the thickness of the equilibrium state of a soap film and lead to the creation of new metastable states of larger thickness. The overall behavior is consistent with a picture in which chains form depletion layers near the surfactant walls, inducing an attractive interaction between the monolayers at large polymer concentrations.