From Bola‐amphiphiles to Supra‐amphiphiles: The Transformation from Two‐Dimensional Nanosheets into One‐Dimensional Nanofibers with Tunable‐Packing Fashion of n‐Type Chromophores

With a rational design of the supra‐amphiphiles, we have successfully demonstrated that not only the dimension of the self‐assembled nanostructures, but also the packing fashion of the functional naphthalene diimide (a typical n‐type chromophore), can be tuned in a noncovalent way in aqueous solution. Naphthalene diimide is incorporated into a bola‐amphiphile as the rigid core, whereas viologen derivatives are used as the hydrophilic head. The bola‐amphiphile self‐assembles into two‐dimensional nanosheets, in which naphthalene diimide adopts a “J‐type” aggregation. Water‐soluble supramolecular complexation between viologen derivatives and the 8‐hydroxypyrene‐1, 3, 6‐trisulfonic acid trisodium salt is used as a driving force for the formation of the supra‐amphiphiles. Upon formation of the supra‐amphiphiles, the nanosheets transform into ultralong nanofibers with a close packing of naphthalene diimide. Notably, just by mixing the two building blocks of the supra‐amphiphiles in aqueous solution, a dimension‐controlled evolution of the nanostructures is formed that leads to a different packing fashion of the n‐type functional chromophores, which is facile and environmental friendly.