Fluorescent robust photoactuator via photo-crosslinking induced single-layered janus polyimide

Advanced smart polymer materials with the ability of reversible deformation under external stimuli hold great potential in robotics, soft machines, and flexible electronics. However, the complexity and low efficiency for fabricating actuators along with their limited functionality hinder further progress. Here an efficient and mild catalyst-free thiol-yne click polymerization was developed to fabricate photosensitive polyimide (PI) films. Then the fluorescent robust photoactuators with single-layered janus structure were directly obtained via UV assisted photo-crosslinking of the films, exhibiting reversible response driven by a pronounced mismatch in expansion between the front and back sides of the films. Achieving selective, non-uniform spatial distribution within the PI films, rapid and reversible complex morphing of the actuators, along with the capabilities for encrypting, reading, and erasing fluorescent information—all through the use of a single UV light source—becomes straightforward. The robust mechanical property and driving ability of these actuators enable the conversion of light energy into obvious motion even under heavy loads and the leaping through the storage and release of energy, ensuring their potential for practical applications that require durability and reliability. The limited functionality and complex fabrication of polymer material with externally controlled reversible deformation hinder their further development. Here, the authors produce fluorescent and robust photoactuators with single layered janus structure for different applications.