Solvent-dependent self-assembly and morphological transition of low-molecular-weight azobenzene organogel

A novel low molecular weight organogelator (LMOG) containing an azobenzene group has been designed and synthesized. Stable gels could be formed in various organic solvents. UV Vis spectroscopy indicated that the sol-gel transition of the organogels could be reversibly tuned by UV/visible light irradiations. Importantly, scanning electron microscopy (SEM) revealed that the characteristic gelation morphologies would vary from solvents of different polarities. FT-IR, XRD and rheological measurements demonstrated that the different nanostructures in polar and non-polar solvents might result from the differences in the intermolecular hydrogen bonding, pi-pi stacking driving forces as well as the different stacking models for the formation of the gels. Moreover, as an efficient phase-selective gelator, this photo-switchable gel could perform as an efficient absorbent and water cleaner to remove pollutants (e.g. rhodamine B). (C) 2017 Elsevier Ltd. All rights reserved.