Fabrication of Smart pH-Responsive Fluorescent Solid-like Giant Vesicles by Ionic Self-Assembly Strategy

A fluorescent solid-like giant vesicle was prepared by using an anionic dye methyl orange (MO) and an oppositely charged surfactant 1-tetradecyl-3-methylimidazolium bromide (C14mimBr) on the basis of the ionic self-assembly (ISA) strategy. The properties of MO/C14mimBr complexes were comprehensively characterized. The results indicated that the giant vesicle was formed by the fusion of small vesicles and could keep its original structure during the evaporation of solvent. Besides, the giant vesicles exhibit luminescent property owing to the break of intermolecular π–π stacking of MO, which achieves the transformation from aggregation-caused quenching to aggregation-induced emission by noncovalent interaction. Moreover, MO/C14mimBr complexes also exhibit smart pH-responsive characteristics and abundant thermic phase behavior. That is, various fluorescent structures (polyhedron, giant vesicle, chrysanthemum, peony-like structure) were obtained when pH ≥ 4, whereas a simple nonfluorescent structure (microfla...