COLL 413 |
| Cesar Marquez and Dominique Langevin. Laboratoire de Physique des Solides, Université Paris Sud, Batiment 510, Orsay, 91405, France |
| We have investigated the oscillations of the disjoining pressure, corresponding to film stratification, of foam-films containing ionic surfactants and carboxymethylcellulose, an anionic polysaccharide having a moderately rigid backbone. With the anionic surfactant, AOT, the polyelectrolyte does not form surface complexes. However, when mixed with cationic surfactants, here alkytrimethylammonium bromides (CnTAB), strong polymer-surfactant interactions create an enhanced co-adsorption of both components at the air-water interface. We have found stratification phenomena independently of the nature of interactions with the surfactant. The oscillation period of the disjoining pressure varies as the inverse square root of C, C being the polymer concentration, and is close to the mesh size of the semi-dilute polymer solution. This is a found earlier with either flexible or rigid polyelectrolytes. The dynamic properties of the liquid films and their stability are in turn very sensitive to the nature of the surfactant charge and to the rigidity of the polymer backbone, as revealed from the behavior of the stratification kinetics. |
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ACS Award in Colloid and Surface Chemistry Symposium Honoring Clay Radke
Division of Colloid and Surface Chemistry |