Giant vesicles composed of cationic lipids having an imine linkage and oleic acid were stable at strong acidic conditions.

There have been several attempts to construct supramolecular chemical systems that mimic the phase transitions in living systems. However, most of these phase transitions are one‐to‐one and induced by one stimulus or chemical; there have been few reports on the pathway‐dependent phase transition of supramolecular self‐assemblies in multi‐step. To induce multistep phase transitions, molecular crystals were prepared that contained a cationic amphiphile bearing azobenzene and disulfide groups. A reducing agent caused the crystals to become vesicles, and adjacent, non‐touching vesicles fused under UV and subsequent visible light. Adding a reducing agent to the worm‐like aggregates that were generated after UV irradiation of the original crystals resulted in the growth of sheet‐like aggregates. 1H NMR and fluorescence anisotropy measurements showed that a series of phase transitions was induced by changes in the phase structures from molecular conversions of the reactive amphiphiles. The multiple pathway‐dependent phase transitions of supramolecular self‐assemblies can provide a methodology for developing new stimuli‐responsive materials that exhibit the desirable properties under specific circumstances from a systems chemistry viewpoint.

The Nobel Prize in Chemistry was awarded in 1987 and 2016 for research in supramolecular chemistry on the “development and use of molecules with structure-specific interactions of high selectivity” and the “design and production of molecular machines”, respectively. This confirmed the explosive development of supramolecular chemistry. In addition, attempts have been made in systems chemistry to embody the complex functions of living organisms as artificial non-equilibrium chemical systems, which have not received much attention in supramolecular chemistry. In this review, we explain recent developments in supramolecular chemistry through four categories: stimuli-responsiveness, time evolution, dissipative self-assembly, and hierarchical expression of functions. We discuss the development of non-equilibrium supramolecular systems, including the use of molecules with precisely designed properties, to achieve functions found in life as a hierarchical chemical system.