Self-Assembly of Azobenzene Derivatives into Organogels and Photoresponsive Liquid Crystals.

A new class of coil-rod-coil molecules with an azobenzene core was synthesized. They were found to form robust organogels in several organic solvents. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), FTIR spectroscopy, UV/Vis absorption spectroscopy, H NMR spectroscopy, and X-ray diffraction (XRD) revealed that in these organogels, the molecules self-assembled into a nanofiber network with an H-type aggregation mode under the joint effect of π-π stacking, intermolecular hydrogen bonding, and van der Waals forces. Interestingly, the incorporation of the azobenzene mesogene into the rigid core led to photoisomerizable liquid crystal materials, which exhibited quick responsiveness to light and temperature, along with the trans-cis transition stimulated by UV light and heating.