A physical operation of hydrodynamic orientation of an azobenzene supramolecular assembly with light and soundElectronic supplementary information (ESI) available. See DOI: 10.1039/c4cc02078b

Photoisomerizations of a newly designed azobenzene derivative reversibly change its self-assembly in a solution to form twisted supramolecular nanofibers and amorphous aggregates, respectively. When irradiating the sample solution with audible sound, the former assembly exhibits a LD response due to its hydrodynamic orientation, but the latter one is LD silent, in the sound-induced fluid flows. Photoisomerizations of a newly designed azobenzene derivative reversibly change its self-assembly in a solution to form twisted supramolecular nanofibers and amorphous aggregates, respectively, and turns their capability for acoustic alignment on and off.