Hierarchical Coordination Polymer–Polymer Composites for Robust, Programmable Photomechanical Actuation

Abstract

ABSTRACT Photoresponsive coordination polymers offer precise molecular‐to‐macroscopic control of mechanical motion, yet their brittleness and limited processability constrain practical implementation. Here we report a hierarchical composite strategy that embeds a one‐dimensional Zn(II) coordination polymer capable of topochemical [2+2] cycloaddition within a poly(vinyl alcohol) matrix and coats it with poly(ε‐caprolactone), yielding mechanically robust, scalable, and water‐stable photomechanical films. The composites exhibit wavelength‐selective activation and expansion‐programmable deformation, enabling dual‐stage bending and radial expansion with actuation fidelity exceeding 98% over extended storage and radial strengths approaching those of load‐bearing polymeric systems. Comparative analysis across representative photoactuating materials identifies a distinct regime combining crystalline photochemical precision with macroscopic mechanical resilience. These results establish general design principles—topochemical preorganization, hierarchical stress transfer, and protective coating—for translating lattice‐confined photochemistry into durable, expansion‐programmable mechanical actuation, providing a foundation for next‐generation adaptive and deployable material systems.