Photoresponsive physical gels using liquid crystals (LCs) as solvents have attracted great interest owing to their potential applications. But current investigations mainly focus on UV light, which is not environment-friendly enough. On the other hand, the halogen bond is a novel tool for constructing supramolecular gels because of its good hydrophobicity, high directionality, tunable strength, as well as large size of halogen atoms. Herein, to construct a LC physical gel with both the advantages of halogen bond and visible light response, azopyridine-containing Azopy-C10 is chosen as a halogen bond acceptor, while 1,2-bis(2,3,5,6-tetrafluoro-4-iodophenyl)diazene (BTFIPD) is selected both as the halogen bond donor and for the intrinsically visible light response. Such a binary gelator can self-assemble in the anisotropic solvent of nematic LC 5CB to form a LC physical gel. It experiences the gel-to-sol transition by green light irradiation. As the gelator concentration increases, the saturation voltage increases, but the switch-off time decreases. The combination of halogen bond and controllable visible light responsive LC physical gel provides the feasibilities of manipulating these smart soft materials.
Intrinsically Visible Light-Responsive Liquid Crystalline Physical Gels Driven by Halogen Bond.