Efficient molecular motors in liquid crystal networks enable the integration of fluorescence with large opto-mechanical effects

Abstract Liquid crystal polymer networks (LCPNs) exhibit remarkable light-responsive actuation, yet the molecular-level design rules governing their performance remain elusive. Here, we develop a series of molecular motor-based photo-responsive units with tunable rigidity, and different substituents, enabling precise modulation of LCPN mechanics and photo-responsive behavior. By systematic study and comparing these motors with conventional azobenzene and second-generation molecular motors, we establish clear structure-property relationships that link molecular design to macroscopic actuation efficiency and network stiffness. Notably, our motor-integrated LCPNs also exhibit intrinsic fluorescence, enabling shape-encoded pattern visualization without the need for additional fluorescent molecules. This multifunctional liquid crystal-motor hybrid system integrates light-induced actuation, mechanical tunability, and fluorescence signaling, offering design principles for next-generation soft actuators and intelligent photonic devices.