Aqueous Sugar-Based Amphiphile Systems: Recent Advances in Phase Behavior and Nanoarchitectonics

Currently, numerous fascinating molecular assemblies are used in food, cosmetics, and pharmaceuticals. Sugar-based amphiphiles are representative constituents of these molecular assemblies. Despite numerous studies on these generic compounds, many aspects remain unexplored even in aqueous systems. In this review, molecular assembly studies of sugar-based amphiphiles in aqueous systems are summarized. First, recent advances in molecular assembly studies, including the glassy state of lyotropic and thermotropic liquid crystalline (LC) phases, modulated crystal phases, and coagels consisting of nanofibers of alkyl β-D-glycosides, are presented. Second, research on thermotropic LC phases under desiccated conditions of trehalose fatty acid monoesters to clarify the fundamental behaviors of the glassy state and their use as stabilizers of glass-forming surfactants for pharmaceutical applications are discussed. Several effective X-ray analytical approaches are included to identify or clarify these phenomena, unknown or unsolved for a long time. Third, a comprehensive analysis of vitamin E (tocopherol)-cyclodextrin in aqueous systems is presented. Along with these topics, the importance of investigating stabilizer-free functional components, considered minor components, is highlighted. These unveiled phenomena or concepts will contribute to the development of nanoarchitectonics covering the self-assembly and selforganization of soft molecules.