Orthogonal Reversible Chemistries Affording Multistate Photoswitching in Polymers for Recyclable Intelligent Material Systems

The wide applications of intelligent material systems in robotics, flexible devices, AI‐driven techniques, and other high‐tech areas call for the development of recyclable intelligent material systems toward a sustainable future. However, intelligent material systems typically comprise multiple components with heterogeneous structures that usually interfere with or cross‐contaminate each other during operation or recycling. Here, we design recyclable intelligent material systems based on orthogonal reversible chemistries, specifically photoisomerization of azobenzene and metal‐ligand coordination of ruthenium complexes. We create a material, P1‐Ru1, by crosslinking an azobenzene‐containing polymer with a ruthenium complex. P1‐Ru1 switches among multiple states that serve as structural elements, shape‐changing modules, adhesives, and other components in intelligent material systems such as soft machines. Crucially, multicomponent, heterogeneous intelligent material systems constructed using different states of P1‐Ru1 can be recycled via a one‐pot, cross‐contamination‐free process because all components share the same chemical origin. This work demonstrates that orthogonal reversible chemistries make intelligent responses and recyclability compatible in complex systems. Orthogonal reversible chemistries offer a new strategy for designing recyclable intelligent material systems with multiple components and heterogeneous structures for sustainable high‐tech applications.