Hierarchical self-assembly of phenazine-based amphiphiles into photosensitive polymorphic nanostructures in aqueous media

[Display omitted] •Hierarchical supramolecular assemblies were achieved via the regulation of the weak intermolecular interactions of D-A type amphiphiles comprising a dibenzo[a,c]phenazine core and phenylacetylene linked by oligopolyethylene chains.•Nanosheets, nanotubes and fibrous helixes were constructed through tuning of donor–acceptor π-stacking and dipolar interactions by introducing sterically hindered lateral groups.•Nanotubes formed by phenazine-based amphiphiles with lateral hexyl and methyl groups exhibited remarkable 1O2 generation and were used as photosensitizers for the photodegradation of rhodamine 6G in aqueous media. In this study, we describe the self-assembly behavior of T-shaped amphiphiles T1-T3 in aqueous solution. These amphiphiles consist of a dibenzo[a,c]phenazine core connected to phenylacetylene via various oligopolyethylene glycol monomethyl ether or hexane segments. Our findings reveal that these molecules self-assemble into sheets and helical nanotubes, which exhibit different helical handedness depending on the presence of hexane or chiral groups. Interestingly, transmission electron microscopy and atomic force microscopy analyses revealed the hierarchical assembly of nanotubes at different concentrations and times. The formation of achiral nanotubes by the self-assembly of T2 with additional hexane chains was attributed to the twisting of the ribbons. In contrast, the introduction of chiral groups in T3 activated further polymerization of the metastable nanorings, resulting in the formation of chiral nanotubes. These nanostructures with particular arrangements exhibit distinct photosensitive properties. Notably, the hollow aquatic aggregates exhibit exceptional singlet oxygen generation efficiency, indicating their potential for applications in wastewater treatment.