Light-Driven Spiral Deformation of Supramolecular Helical Microfibers by Localized Photoisomerization

Stimuli-responsive mechanical deformations widely occur in biological systems but the design of biomimetic shape-changing materials, especially those based on noncovalent interactions, remains highly challenging. Here, hydrogen-bonded supramolecular microfibers are reported, which can perform light-driven spiral deformation by switching an intrinsic azobenzene unit without monomer dissociation. The key design feature rests on rationally spaced multiple hydrogen bonds, which inhibits the disassembly pathway upon irradiation, allowing partial photomechanical actuation of the azobenzene cores in the confined environment of the assemblies. The light-controlled deformation process of the supramolecular microfibers can be switched in a fully reversible manner. This combination of confinement-inhibited disassembly and photoswitching to induce assembly deformation and actuation along length scales supports a distinctive strategy to design supramolecular materials with photomechanical motion.