Monteux C, Williams C E, Meunier J, Anthony O, Bergeron V
Laboratoire de Physique Statistique, UMR 8550, Ecole Normale Supérieure, 24 rue Lhomond, 75005 Paris, France.
Langmuir. 2004 Jan 6;20(1):57-63. doi: 10.1021/la0347861.
The adsorption and complexation of polystyrene sulfonate (a highly charged anionic polyelectrolyte) and dodecyltrimethylammonium bromide (a cationic surfactant) at the air-water interface can lead to interfacial gels that strongly influence foam-film drainage and stability. The formation and characteristics of these gels have been studied by combining surface tension, ellipsometry, and foam-film drainage experiments. Simultaneously, the solution electromotive force is measured and used to track the polymer-surfactant interactions in the bulk solution. We find that surface gelation occurs above the critical aggregation concentration in solution but before bulk precipitation of the polymer-surfactant complexes. Furthermore, we reveal that strong readsorption of polymer-surfactant complexes occurs during the resolubilization of the precipitated complexes at high surfactant concentrations (i.e., >>critical micelle concentration). Seemingly overlooked in the past, this readsorption significantly influences the surface rheological properties and foam-film drainage of these systems.
聚苯乙烯磺酸盐（一种高电荷阴离子聚电解质）和十二烷基三甲基溴化铵（一种阳离子表面活性剂）在气-水界面的吸附和络合会导致形成界面凝胶，这种凝胶会强烈影响泡沫膜的排水和稳定性。通过结合表面张力、椭偏仪和泡沫膜排水实验，对这些凝胶的形成和特性进行了研究。同时，测量溶液的电动势并用于追踪本体溶液中聚合物-表面活性剂的相互作用。我们发现，表面凝胶化发生在溶液中的临界聚集浓度之上，但在聚合物-表面活性剂络合物的本体沉淀之前。此外，我们还揭示，在高表面活性剂浓度（即远高于临界胶束浓度）下沉淀的络合物再溶解过程中，聚合物-表面活性剂络合物会发生强烈的再吸附。过去似乎被忽视了，这种再吸附会显著影响这些体系的表面流变性质和泡沫膜排水。
