Chemotaxis of Oil Droplets and Their Phase Transition to Aggregates with Membrane Structures in Surfactant Solution Containing Metal Salts.

The movement of supramolecular self‐assemblies has been induced by the application of external stimuli that cause a shift to non‐equilibrium conditions. However, few supramolecular chemical systems exist in which multiple different functions are associated with movement. Herein, we observed multiple phase transition of micrometer‐sized lauronitrile oil droplets in a solution of cationic surfactants with aniline skeletons in the presence of metal ions. These dynamics include tactic motion and subsequent formation of aggregates with membrane structures, in a linear‐type channel. These dynamic behaviors result from variations in the interfacial tension at the droplet surface and the chemical compositions owing to the interactions between system components. The current findings may provide a methodology for designing molecular systems in which multi‐step phase transitions of supramolecular self‐assemblies are coupled to movement in non‐equilibrium conditions. [ABSTRACT FROM AUTHOR]