Based on charge-transfer interaction organic light-response materials: From sphere-like nanoparticles to fibers

We employed a potent and versatile ionic self-assembly (ISA) to prepare stimuli-responsive supramolecular materials using charged surfactants, N-dodecyl-4-(1-methylpip-erazine)-1,8-naphthalimide iodine [C12ndi]I and oppositely charged small molecule, 4-(phenylazo)benzoic acid sodium (PBAS). By transmission electron microscopy, nanospheres could be observed to transform into nanofibers upon irradiated with UV light (365 nm) for 1 h. The UV–vis absorption spectra and fluorescence spectra of the fibers indicate that charge-transfer interaction is regarded as the driving force for the formation of fibers. Density functional theory (DFT) calculations prove that the π–π stacking and electrostatic interactions between [C12ndi]I and PBAS contributes significantly to the resulting aggregates. The supramolecular fibers have the potential applications in some fields, e.g. drug delivery and electro-optical devices.