Photoresponsive Supramolecular Soft Actuators via Co-assembly of Azobenzene Bola-Amphiphiles: From Nanostructure Transformations to Enhanced Actuation Properties

Nature serves as an inspiration for the controlled supramolecular assembly of biomimetic units, which can be finely tuned through specific supramolecular interactions. Supramolecular actuators, which rely on weak intermolecular forces such as hydrogen bonding, hydrophobic effects, and π–π stacking, exhibit high dynamicity and stimuli-responsiveness. However, most reported supramolecular actuators based on azobenzene amphiphiles have been fabricated primarily through self-assembly strategies and optimized via molecular modifications. In this context, azobenzene bola-amphiphiles ( ABA s) functionalized with anionic sulfate and cationic 1-methylimizadolium end-groups were designed and synthesized, exhibiting excellent photochemical and supramolecular self-assembly properties. Importantly, the coassembly of anionic and cationic ABA s resulted in the formation of sheet-like nanostructures, which significantly enhanced the photoactuation performance, achieving actuation speeds up to 13.17 ± 1.85°/min under 365 nm light irradiation. The effective coassembly strategy of light-responsive supramolecular actuators shed light on the development of the next generation of supramolecular soft robotic systems.