INTERACTIONS BETWEEN POLYMERS AND SURFACTANTS

A surfactant film (at the water/air interface, or in a bilayer) is exposed to a solution of a neutral, flexible, polymer. Depending on the interactions, and on the Langmuir pressure II of the pure surfactant film, we expect to find three types of behavior: (I) The polymer does not absorb. (II) The polymer absorbs and mixes with the surfactant. (III) The polymer absorbs but segregates from the surfactant. Our interest here is in case II. We predict that (a) bilayers become rigid; (b) bilayers, exposed to polymer on one side only, tend to bend strongly; (c) the surface viscosity of monolayers or bilayers is considerably increased; soap films or foams, which usually drain by turbulent (two-dimensional) flows, may be stabilized in case II. © 1990 American Chemical Society.