Creation of photo-modulated multi-state and multi-scale molecular assemblies via binary-state molecular switch

The creation of photo-modulated multi-state and multi-scale molecular self-assemblies was realized by the ingenuous utilization of a binary-state molecular switch, sodium (4-phenylazo-phenoxy)-acetate (AzoNa). Depending on the irradiation time, the binary state of the azobenzene group (i.e. trans/cis isomerization) can be exploited to generate multi-state nanostructures (including wormlike micelle, vesicle, lamellar structure, small micelle) by the coupling of conventional surfactant CTAB. Meanwhile, the conformation transition of azobenzene at molecular scale (similar to angstrom), stimulated by light input can be amplified to regulate molecular architectures at mesoscopic scale (from nanometer to micrometer), leading to significant changes in solution property at macroscopic scale (naked-eye visible scale). By exposing to UV or visible light, the multi-state and multi-scale molecular self-assemblies can be reversibly controlled. It is proposed that light-triggered structural changes in the dipole moment and geometry of azobenzene group, which impart a significant effect upon molecular packing of surfactant aggregates, were responsible for this peculiar phenomenon.