Liquid crystalline nanoparticles formed by oppositely charged surfactant-polyelectrolyte complexes

Polyelectrolyte-surfactant (PE-S) complexes holding liquid crystalline (LC) structures have been widely studied over the last twenty years due to potential application in different fields. Several variables influence on important features of these PE-S complexes, such as surfactant and polyelectrolyte chemical structure (molecular architectures), charge molar ratio, environmental (pH, temperature, ionic strength) and mixing conditions (since non equilibrium structures can be obtained), among many others that are discussed in this review. Depending on such variables, the PE-S complexes may display a variety of sizes, shapes, arrangements and LC phases. The short-range molecular arrangement is driven by the surfactant self-assembly though strongly influenced by the polyeletrolyte and also dependent on the presence of co-solutes (typically co-surfactants). In general, these structures reproduce features observed in the phase diagrams of surfactants for similar systems, which could then be used to tailor the formation of specific liquid crystalline structures. These correspondences are highlighted in this review along with some remarkable features reported for PE-S complexes and their consequences for potential applications. (C) 2017 Elsevier Ltd. All rights reserved.