ABSTRACT
Mixed surfactant-surfactant [1-5] and polymer-surfactant systems [6-10] have been in the past decade in the forefront of significant basic research, often with strong implications in applied areas, since they display a number of very versatile interfacial and aggregation properties. Systems comprising polymers and surfactant vesicular aggregates, in particular, are reviewed in this chapter, with special reference to mixtures where oppositely charged cosolutes are present. Features such as associative phase separation, formation of thermodynamically stable vesicles, and polymer-vesicle aggregation are herein addressed, which are based on a number of reports [11-16]. The experimental work includes phase diagram determination, self-diffusion nuclear magnetic resonance (NMR), light and electron microscopy, and rheology With regard to phase behavior, there is a close analogy between polyelectrolyte-vesicle mixtures and previous studies of polyelectrolyte-micelle mixtures, with an associative phase separation in a wide range of charge stoichiometries. Interesting novel gels are identified in phase maps and their structures discussed with reference to cryo-transmission electron microscopic (cryo-TEM) results. The interactions between DNA and mixed cationic-anionic vesicles, only recently investigated, are also addressed, with direct imaging evidence for the adsorption configuration of the macromolecule.
