Photo/chemo dual-controlled reversible morphological conversion and chiral modulation of supramolecular nanohelixes with nanosquares and nanofibers.

A photo/chemo dually interconvertible system was constructed through the supramolecular assembly of azobenzene-diphenylalanine (Azo-FF) with α-cyclodextrin. The resultant chiral nanohelix was able to interconvert into a nanosquare upon irradiation at different wavelengths, but into a nanofiber upon changing solvent polarity, which provides a feasible way to achieve highly ordered nanostructures with various morphologies, dimensions and chiralities.