Photo‐Controlled Dynamics of Cholesteric Polymer Coatings via Hydrazone Crosslinking

Abstract

Abstract Developing responsive coatings and materials requires discovering a breadth of mechanisms by which external stimuli can be converted into useful signals. Here, we demonstrate an approach driven by supramolecular mechanochemistry, where mechanical input—molecular shape change—is translated into structural color variation. By embedding bistable, negatively photochromic hydrazone photoswitches into cholesteric polymer networks, we achieve a reversible, stable color shift through molecular‐scale pulling and pushing of the photonic scaffold. Unlike azobenzene‐based systems, which typically disrupt liquid crystal order, this approach modifies the pitch of a cross‐linked cholesteric helix without disrupting the organisation of the material. The long‐lived stability of both hydrazone isomers ensures durable optical switching. This effect provides a new strategy for designing mechanoresponsive photonic coatings and tunable optical materials.